- Chimera-users - RBVI Mailing Lists

Question about unit of electron density
by Matthias Fellner 13 Oct '14

13 Oct '14

Dear Elaine Thank you for the long response and sorry for my late one as I just finished a publication where I used Chimera for the first time and also cited it. You answered everything I wanted to know. So I wanted to wait for my thanks to see if I can ask another question right away: What unit do I report for the "level" of a shown electron density map. I assume it is σ (lower case letter sigma) for example 1.2σ? I just could not find the unit in the tutorial or a search through your board, so I wanted to double-check. Thank you Matthias Fellner ________________________________________ From: Elaine Meng [meng(a)cgl.ucsf.edu] Sent: 04 October 2014 06:50 To: Matthias Fellner Cc: chimera-users(a)cgl.ucsf.edu Subject: Re: [Chimera-users] Question about RMSD calculation of MatchMaker Hi Matthias! As shown in your image of the dialog, you’re using the “Iterate by pruning…” option that removes farther-apart pairs from the fit. That’s why you could get different numbers of pairs used to calculate the RMSD even if all chains contain the same numbers of residues. Iteration is described in the MatchMaker docs: <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/matchmaker/matchm…> If you turn off the “iterate” option, it will not try to improve the fit by pruning and will instead use all the pairs (CA-CA atom pairs of residues aligned in the sequence alignment). If the structures include the same residues for each chain, the pairwise chain-chain RMSDs will all be calculated from the same number of CA-CA atom pairs. The dialog image also shows you are fitting A-B, A-C, A-D. For completeness you may also want to try B-C, B-D, C-D. Another issue is that MatchMaker or its command equivalents (mmaker, matchmaker) only use one atom per residue, CA, and only considers aligned biopolymer chains (peptides, nucleic acids). If that’s what you want, no worries. However, you could use the “match” command instead and specify any sets of atoms for RMSD calculations, such as all backbone, with or without iteration. However, it’s harder to use since you have to specify the atoms in the command line yourself, unlike MatchMaker that figures out which atoms to pair automatically. You could include waters, but it would be tedious/difficult to specify each water residue by name, in the corresponding orders, for the two structures to be matched. Also the waters would have to be in the respective models. Matchmaker vs. match is discussed in the following link: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/superposition.html> “match” command manpage, examples: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/match.html> command-line atom specification: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/atom_spec.html#basic> another “match” example in a tutorial, see the Matching section in: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/tutorials/frameimages.html> If you are interested in the variation over the length of the chain as opposed to getting a single number, a nice way to show that is to first superimpose the chains, then associate them all with a single copy of the sequence. Then over the sequence you can display an RMSD histogram showing the alpha-carbon (or other atoms, depending on which RMSD you choose) structural variability at each position in the sequence. To do that: (1) superimpose chains however you like (Matchmaker or match) (2) show sequence of any one of them, presumably they are basically the same (menu: Favorites… Sequence, choose one) (3) in the sequence window, use Structure… Associations to associate all copies of the structure with the single sequence (4) in the sequence window, use the Headers menu to show the RMSD of interest (and hide other headers you don’t want to see) You can even show these RMSD values with colors or worm thickness on one of the copies, as described in more detail here: <http://plato.cgl.ucsf.edu/pipermail/chimera-users/2014-March/009710.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco On Oct 1, 2014, at 9:38 PM, Matthias Fellner <mfellner(a)chemistry.otago.ac.nz> wrote: > Good day > > I am a PhD student at the University of Otago New Zealand. First I would like to thank you for this very useful software, I use it for all my protein crystallography pictures and a lot of analysis as well, I will use a citation for sure when I publish using your software. > A current analysis of mine involves a crystal structure that has 4 chains in the asymmetric unit. They chains are very similar when aligned and I would like to have a statistic to show this. > > I assume the RMSD is the way to go. So I saved each chain as its own pdb, loaded them in Chimera and used your MatchMaker to align chain B,C and D to chain A (randomly chosen because of notation of chains). > > The chains have an identical amino acid sequence (~200 residues), I just build 1-5 residues more or less at each end of the chain but otherwise they should all be the same. Now the reply log gives out the RMSD and the number is under 1Å as I expected and I can quote that. But my question would be why did it use a different numbers of atom pairs for the different chains (191 or 188 or 193) and which atom pairs are those. I assume it picks one atom from the main chain of each residue and the different number comes from the difference residue number at the end of the chains. > > I searched through your help files and with google through your board but could not find the answer to what atoms are paired and if you can change the pair for example to include all atoms of the mainchain or even all atoms all together. > > Sorry for the long question but I wanted to give all the details, attached also the (default) options I had for the MatchMaker and the reply log. > > In addition a small question which I guess wont be possible – is there any way to also align water molecules adjacent to the chains although all water molecules are saved in chain S together? > > Thank you > Matthias > > > <image001.png> > > Matchmaker chainA.pdb, chain A (#0) with chainD.pdb, chain D (#3), sequence alignment score = 999.7 > with these parameters: > chain pairing: bb > Needleman-Wunsch using BLOSUM-62 > ss fraction: 0.3 > gap open (HH/SS/other) 18/18/6, extend 1 > ss matrix: (O, S): -6 (H, O): -6 (H, H): 6 (S, S): 6 (H, S): -9 (O, O): 4 > iteration cutoff: 2 > RMSD between 191 atom pairs is 0.506 angstroms > > > Matchmaker chainA.pdb, chain A (#0) with chainC.pdb, chain C (#2), sequence alignment score = 999.1 > with these parameters: > chain pairing: bb > Needleman-Wunsch using BLOSUM-62 > ss fraction: 0.3 > gap open (HH/SS/other) 18/18/6, extend 1 > ss matrix: (O, S): -6 (H, O): -6 (H, H): 6 (S, S): 6 (H, S): -9 (O, O): 4 > iteration cutoff: 2 > RMSD between 188 atom pairs is 0.551 angstroms > > > Matchmaker chainA.pdb, chain A (#0) with chainB.pdb, chain B (#1), sequence alignment score = 987.2 > with these parameters: > chain pairing: bb > Needleman-Wunsch using BLOSUM-62 > ss fraction: 0.3 > gap open (HH/SS/other) 18/18/6, extend 1 > ss matrix: (O, S): -6 (H, O): -6 (H, H): 6 (S, S): 6 (H, S): -9 (O, O): 4 > iteration cutoff: 2 > RMSD between 193 atom pairs is 0.336 angstroms > _______________________________________________ > Chimera-users mailing list > Chimera-users(a)cgl.ucsf.edu > http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users

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Measuring volume inside virus caspid
by Tom Goddard 13 Oct '14

13 Oct '14

Hi Reggie, I measure the volume inside the capsid of bacteriophage P22 from Electron Microscopy Databank entry 1220 as about 77,000 cubic nanometers. Here’s how I calculated it in Chimera. The idea is to fit a surface that is something between an icosahedron and a sphere to the inside of the capsid then measure the volume within that surface. The Chimera Icosahedron Surface tool (menu Tools / Higher-Order Structure) can make this surface. But the problem is that the EMD 1220 density map is not in a standard icosahedral orientation. The closest orientation is 2-fold symmetry axis along x, 3-fold symmetry axis along z (called 2n3r in Chimera). That orientation looks to be about 5 degrees out of alignment with the virus. So I set the radius to 320 (about the size of the capsid), sphere factor to 0.5 to approximate the spherical shape of the virus, and subdivision factor to 100. Then I created a density map that is ones inside this surface and zeros outside with the command “mask ones #1” (the icosahedron surface is model #1, as shown in the Model Panel dialog, Favorites menu). Then I fit this icosahedron map to EMD 1220 to get the correct alignment using the Fit in Map tool (menu Tools / Volume Data / Fit in Map, fit #2 in #0). I judge the fit is good by seeing that the virus capsid proteins stick out uniformly from the surface of the fit mask map. Then I align the original icosahedron surface to the fit mask using “matrixcopy #1 #2”. Then I adjust the icosahedron surface radius and sphere factor (285 and 0.54) to visually match the inner boundary of the EMD 1220 capsid. To see that I clip the EMD 1220 map in half using Per-Model Clipping (menu Tools / Depiction). Then I measure the enclosed volume of that aligned icosahedron surface using the Measure Volume and Area tool (menu Tools / Volume Data), and I get 77 million cubic Angstroms, or 77,000 cubic nanometers. See attached picture with aligned icosahedron surface shown transparent and brown. Tom On Oct 13, 2014, at 10:40 AM, Reginald McNulty wrote: > Hi Tom, > Can you tell me the tricks of how to calculate the volume of just the interior for EMD-1220? > Reggie > > On Oct 9, 2014, at 5:58 PM, Tom Goddard wrote: > >> Hi Reggie, >> >> What are you trying to calculate? Chimera can calculate the volume inside your density map surface if that is what you want. If it is just a capsid map then it won’t include the hollow interior. There are tricks to include the interior. If you really care about icosahedron volumes Chimera gives the exact value by summing polyhedral volumes. The Chimera icosahedron radius is the distance from the center to a vertex. The measure volume command reports the enclosed volume of the icosahedron with its flat faces as 58.7e6 for radius 285. As you note a sphere of radius 285 has volume 95e6. >> >> Tom >> >> >> On Oct 9, 2014, at 5:34 PM, Reginald McNulty wrote: >> >>> Dear Tom, >>> >>> Eager to hear your thoughts on what’s below. >>> >>> I’ve done the math by hand for how to calculate the volume of an icosahedron. One of them (exsphere) gives the exact answer shown in Chimera with 'measure volume'. I’ll give a brief definition below and then show all calculations. The volume (V) of an icosahedron depends on the length of the edge (distance between five folds). My understanding is that there are different ways of drawing the radius (R) to calculate the length of an edge (a). Assuming an exsphere radius of 285 angstroms, I can calculate a volume of 58709669.80741614 cubic angstroms (or 59 million cubic angstroms) which is exactly the answer shown in chimera. However, I suspect the midsphere radius of 285 angstroms, yielding a volume of 95379640.39879936 cubic angstroms (or 95 million cubic angstroms) is a closer approximation, as this answer is very close to that obtained assuming V=4/3*(pi)*r^3 (97 million cubic angstroms). >>> >>> Definitions: >>> Inscribed sphere: http://en.wikipedia.org/wiki/Inscribed_sphere >>> Midsphere: http://en.wikipedia.org/wiki/Midsphere >>> exsphere: http://en.wikipedia.org/wiki/Exsphere_(polyhedra) >>> >>> Useful online calculator: http://calcverter.blogspot.com/2014/08/icosahedron-edge-area-volume-exspher… >>> >>> Assuming a radius of 285 angstroms, here are the calculations for volume 3 different ways: >>> >>> Method A >>> R(m)- Midsphere radius= 285 Å >>> >>> R(m)=a / 4 * ( 1 + √5 ) >>> --------------------------------------- >>> multiply both sides by 4 >>> --------------------------------------- >>> 285(4)= a(1+√5) >>> = a(3.23606797749979) >>> ---------------------------------------- >>> a=285(4)/3.23606797749979 >>> ---------------------------------------- >>> a=352.27937358744003 >>> ---------------------------------------- >>> Now that we have the icosahedral edge length (a), we can calculate the volume of the virus with: >>> >>> V= 5 / 12 * a³ * ( 3 + √5 ) >>> >>> = 5/12 * 43718136.95711854 *(3 + √5) >>> = 5/12 *43718136.95711854 5.23606797749979 >>> =95379640.39879936 >>> --------------------------------- >>> or 95 million cubic Å >>> --------------------------------- >>> >>> >>> >>> Method B >>> R(e)- Exsphere radius- 285 >>> >>> R(e) = a / 4 * √(10 + 2 * √5) >>> ---------------------------------- >>> writing in python was easier for me here: >>> >>> 285=a/4 * math.sqrt(10+2*math.sqrt(5)) >>> 285=a/4 * 3.804226065180614 >>> ---------------------------------------------- >>> >>> solve for a: >>> a=(285/ 3.804226065180614)*4 >>> a=299.6667339079062 >>> >>> -------------------------------------------- >>> Now that we have the icosahedral edge length (a), we can calculate the volume of the virus with: >>> >>> V= 5 / 12 * a³ * ( 3 + √5 ) >>> -------------------------------------------------- >>> writing in python is a little easier here: >>> >>> V= ((5/12.0)*(299.6667339079062**3)*(3+math.sqrt(5))) >>> >>> = 58709669.80741614 >>> -------------------------------- >>> or 58 million cubic Å >>> --------------------------------- >>> >>> >>> >>> Method C >>> R(i)- Insphere radius (tangent to face of icosahedran) >>> >>> R(i) = a / 12 * √3 * ( 3 + √5 ) >>> >>> ----------------------------- >>> >>> 285 = a/12 *((math.sqrt(3))*(3+math.sqrt(5))) >>> >>> 285= a/12 * 9.069135768914048 >>> >>> a= (285/9.069135768914048)*12 >>> = 377.1031868022763 >>> ---------------------------------------- >>> >>> Use edge of 377.1031868022763 to calculate volume >>> >>> V= 5 / 12 * a³ * ( 3 + √5 ) >>> ------------------------------------------- >>> >>> V= ((5/12.0)*(377.1031868022763**3)*(3+math.sqrt(5))) >>> V= 116996977.425189 >>> --------------------------------------------- >>> >>> or 116 million cubic Å >>> >>> ------------------------------------------ >>> >>> Reggie McNulty >>> >>> On Oct 9, 2014, at 4:49 PM, Tom Goddard <goddard(a)sonic.net> wrote: >>> >>>> When you use the “measure volume” command on an icosahedral cage it is measuring the volume enclosed in the polygonal solid defined by the cage, not the volume of a sphere. I don’t know what you mean by “exsphere”, “midsphere”, “calculate by hand”. >>>> >>>> Tom >>>> >>>> >>>> On Oct 9, 2014, at 1:01 PM, Reginald McNulty wrote: >>>> >>>>> I manually fixed the cage and shrunk it to encompass the internal DNA using a radius of 285. I used the measure volume command to measure the volume inside the cage. Can Chimera show sphere it is using to calculate calculate the volume? A cage with radius 285 angstroms gives a volume of 58 million cubic angstroms. By hand, I can calculate volume of also 58 million cubic angstroms using an exsphere radius of 285; edge is 300 angstroms. However, a midsphere radius of 285 gives me an edge of 352 angstroms and volume of 95 million cubic angstroms. >>>>> Reggie >>>>> >>>>> On Oct 8, 2014, at 2:24 PM, Tom Goddard wrote: >>>>> >>>>>> Yes you could probably fix the alignment of a cage by hand in Chimera so it looked decent. If you want to do some analysis using the symmetry that is harder. >>>>>> >>>>>> Tom >>>>>> >>>>>> On Oct 8, 2014, at 2:14 PM, Reginald McNulty wrote: >>>>>> >>>>>>> Never mind. I think it’s close enough with 2fold on x, 3 fold on z, with extra rotation. >>>>>>> On Oct 8, 2014, at 2:07 PM, REGINALD MCNULTY wrote: >>>>>>> >>>>>>>> Thanks. It works. >>>>>>>> I’m trying to do the same thing now for a virus with a tail. It was refined with C1 symmetry. The icosahedral symmetry in the capsid is evident. But I can’t get the icosahedal surface to match the symmetry exactly. Can you take a look at this map: emd_1220.map? >>>>>>>> Reggie >>>>>>>> On Oct 8, 2014, at 11:34 AM, Tom Goddard wrote: >>>>>>>> >>>>>>>>> Hi Reggie, >>>>>>>>> >>>>>>>>> I used the following Chimera commands to create an icosahedral cage for virus capsid 2xyz and density map for full capsid, image attached. >>>>>>>>> >>>>>>>>> Tom >>>>>>>>> >>>>>>>>> open 2xyz >>>>>>>>> rainbow chain >>>>>>>>> sym #0 surf true >>>>>>>>> >>>>>>>>> # Used Tools / Higher-Order Structure / Icosahedron Surface to figure out orientation is n25r (no sym on x, 2-fold on y, 5-fold on z, with extra rotation). >>>>>>>>> >>>>>>>>> shape icos radius 400 orient n25r lattice 2,1 color blue linewidth 5 >>>>>>>>> molmap #0 10 sym i,n25r >>>>>>>>> >>>>>>>>> >>>>>>>>> <2xyz.jpg> >>>>>>>>> >>>>>>>>> On Oct 8, 2014, at 10:40 AM, Reginald McNulty wrote: >>>>>>>>> >>>>>>>>>> Dear Tom, >>>>>>>>>> >>>>>>>>>> I’ve imported a virus capsid shell pdb 2xyz to chimera. I want to measure the symmetry and make a cage based on that symmetry. Molmap seems to only produce a map of the asymmetric unit, not the entire capsid. Any thoughts? >>>>>>>>>> I’m currently following directions that are here: http://www.cgl.ucsf.edu/chimera/videodoc/IcosWedge/index.html >>>>>>>>>> >>>>>>>>>> All the best, >>>>>>>>>> -Reggie >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> Reginald McNulty, Ph.D. >>>>>>>>>> Postdoctoral Research Associate >>>>>>>>>> The Scripps Research Institute >>>>>>>>>> Johnson Lab >>>>>>>>>> Department of Integrative Structural and Computational Biology >>>>>>>>>> 10550, N. Torrey Pines Road, MB-31 >>>>>>>>>> La Jolla, California 92037 >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>> >>>>> All the best, >>>>> -Reggie >>>>> >>>>> -- >>>>> Reginald McNulty, Ph.D. >>>>> Postdoctoral Research Associate >>>>> The Scripps Research Institute >>>>> Johnson Lab >>>>> Department of Integrative Structural and Computational Biology >>>>> 10550, N. Torrey Pines Road, MB-31 >>>>> La Jolla, California 92037 >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>> >>> >> > >

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command @/serialNumber=#
by Francesco Pietra 12 Oct '14

12 Oct '14

Hello: I wonder whether it is possible to extend the command sel @/serialNumber=18801 (as an example of a particular serial number) to comprise a range of atoms. So as to cover, for example, an entire ligand, may be dioxygen, 18801-18802. And whether that could be extended to define a centroid. it is implied that I have prepared a large system based on segname (charmm ff with namd), which is not dealt with by chimera. thanks francesco pietra PS: I can follow the ligand by defining the centroid for a single atom of the ligand. This would be my last resource.

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measuring distance between an atom and centroid of an aromatic ring
by Aswani Kumar Kancherla 10 Oct '14

10 Oct '14

Hello Chimera Users, I need to measure and mark the distances of a few atoms to the center of an aromatic ring. I could define and create a centroid and plane for the ring. However, I am unable to measure or mark the distances of the surrounding atoms from the centroid of the ring (This is an exercise to show the ring current effect of the aromatic ring on the chemical shifts of the neighboring protons). Could anyone please give a hint on how I can go about this? thanking you in advance, best wishes, Aswani -- K.Aswani Kumar Graduate Student Molecular Biophysics Unit Indian Institute of Science Bangalore-560012 Karnataka, India.

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please give advice
by Jane Norman 10 Oct '14

10 Oct '14

Hello I am new to using chimera and I have been struggling with one aspect. I'm trying to mutate one residue in my protein, by using the command swapaa leu :310, this seems to work nicely, To show the amino acid I then go in to "tools" then "sequence" and select this mutated residue and then go to "actions" then "atoms/bond" and "show" and the residue is displayed, however it is displayed as a block colour which I can't seem to change the colour scheme of the amino acid to match other residues which I've displayed nearby (e.g showing different colours (white/blue/red for different groups on the amino acid). i can easily change the block coulr of the whole reside but not to match the helpful scheme of he other displayed residues. However If I just pick an unmutated residue to display it shows it in the same style as the other residues (which is what I want for my mutated one) I hope that makes sense I couldn't find the answer in the help section Thank you very much for your time Jane

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Failed to prepare receptor for AutoDock Vina
by William McDonald 09 Oct '14

09 Oct '14

Hello Chimera users, I am attempting to learn ligand docking using autodock vina in Chimera. I am using a local copy of AutoDock Vina, and Chimera 1.9 (64 bit) for mac os 10.9.5. I have added H atoms to the ligand prior to loading the structure into Chimera. I added H atoms to the protein within Chimera. However, when I run AutpDock Vina I receive the error: ValueError: Could not find atomic number for Ha Ha failed to prepare receptor for AutoDock Vina; please look in Reply Log to see errors. I thought that this could be because of the H atoms added to CA atoms are named HA by default, however if I change the HA atom names to H, I still get the same error. I can verify that there are no atoms named "Ha" in the structure. What am I doing wrong? Thanks for your time. -- William J. McDonald Postdoctoral Scholar Department of Chemistry and Biochemistry University of California, Santa Cruz

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color zones with multiple markers
by Revyakin, Andrey (Dr.) 09 Oct '14

09 Oct '14

Hi Chimera folks, I am a new user of Chimera; trying to simultaneously color different features of a Cryo-EM structure (EMD-2305) with different colors. I select volume tracer and make a marker (looks like a tumour on the structure), and select color zone. The features are large, so I select another marker nearby to expand the color zone (another tumour appears next to the first tumour), but then the color zone associated with the first marker disappears and moves to the next marker. How can I preserve the previously created color zone? I seem to be unable to select multiple markers by holding ctrl and clicking/dragging-- either the whole structure is selected, or only one marker can be selected at a time. I spent an hour looking on the web for a solution, but did not find any. Windows 7, 64 bit. I apologize if this is too trivial of a question. Cheers, Andrey R.

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Energy calculation
by bobo2412＠gmail.com 09 Oct '14

09 Oct '14

Hi, Do you know if chimera can do energy calculation? I have a protein I want to mutate some residues and calculate the energy difference before and after the mutation. Do you know if I can do that in chimera? Thanks, Bobo 发自我的 iPhone

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Re: [Chimera-users] measure symmetry
by Tom Goddard 08 Oct '14

08 Oct '14

Hi Reggie, You are right that the EMDB 1220 virus capsid has none of the standard icosahedral orientations. It is approximately 3-fold axis along z, and 2-fold axis along x (Chimera orientation 2n3r) but it is maybe 5 degrees off from that. If this capsid was refined with C1 symmetry then there is no reason for it to have a standard orientation. It will be difficult to compute the icosahedral symmetry matrices. I suggest you talk to the author of that map Gabe Lander who has a lab at Scripps, right where you are located. Tom On Oct 8, 2014, at 2:07 PM, Reginald McNulty wrote: > Thanks. It works. > I’m trying to do the same thing now for a virus with a tail. It was refined with C1 symmetry. The icosahedral symmetry in the capsid is evident. But I can’t get the icosahedal surface to match the symmetry exactly. Can you take a look at this map: emd_1220.map? > Reggie > On Oct 8, 2014, at 11:34 AM, Tom Goddard wrote: > >> Hi Reggie, >> >> I used the following Chimera commands to create an icosahedral cage for virus capsid 2xyz and density map for full capsid, image attached. >> >> Tom >> >> open 2xyz >> rainbow chain >> sym #0 surf true >> >> # Used Tools / Higher-Order Structure / Icosahedron Surface to figure out orientation is n25r (no sym on x, 2-fold on y, 5-fold on z, with extra rotation). >> >> shape icos radius 400 orient n25r lattice 2,1 color blue linewidth 5 >> molmap #0 10 sym i,n25r >> >> >> <2xyz.jpg> >> >> On Oct 8, 2014, at 10:40 AM, Reginald McNulty wrote: >> >>> Dear Tom, >>> >>> I’ve imported a virus capsid shell pdb 2xyz to chimera. I want to measure the symmetry and make a cage based on that symmetry. Molmap seems to only produce a map of the asymmetric unit, not the entire capsid. Any thoughts? >>> I’m currently following directions that are here: http://www.cgl.ucsf.edu/chimera/videodoc/IcosWedge/index.html >>> >>> All the best, >>> -Reggie >>> >>> -- >>> Reginald McNulty, Ph.D. >>> Postdoctoral Research Associate >>> The Scripps Research Institute >>> Johnson Lab >>> Department of Integrative Structural and Computational Biology >>> 10550, N. Torrey Pines Road, MB-31 >>> La Jolla, California 92037 >>> >>> >>> >>> >>> >>> >> > >

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Re: [Chimera-users] Analysis of the multiple alignments + structures
by James Starlight 08 Oct '14

08 Oct '14

Dear Chimera users! I've been interested in the possibility to make some sort of evolutional analysis in Chimera using MSA of the protein under study, its X-ray structures and its superimpositions as well as obtained projections of the sequence conservation in key (functionally-important) hot spots made by means of mutalign plugin. For my particular case I have MSA for the big number of olfactory receptors sequences (including receptors from different sub-groups associated with different specificity towards different odors). As the result I should to find possibility to sort these sequences of each ORs based on some phylogenetic study (I thinks to obtain tree-like view of the sequences) considering explicitly residues of the receptor's binding site. One of the possible idea is to keep only those residues of interest (from the ligand binding cavity) and rerun the alignment on these mini sequences to make prediction of new family of Or that may interact with the same kind of odorants. Would this idea is better realized by means of differential evolutional tracing method (because In fact we need to subtract conservative residues of one sub-branch of the whole phylogeny tree from those of all (root) OR) or there are any trivial alternatives? Thanks for help, James 2014-09-19 22:04 GMT+02:00 James Starlight <jmsstarlight(a)gmail.com>: > Dear Elaine, > > thanks you very much for the suggestions! It's always a big pleasure to > get advise from the experienced person :) BTW may be the next question will > be more in connection with your present job (Chimera software developer). I > wounder whether it *in principle* possible to find an academic post-doc job > focused mainly on molecular visualization and animation (as the trivial > example os such job in my mind is to make a pictures and movies of the > proteins and it's complexes using data from different resolution's > experimental techniques and modelling). How do you think will it be easily > to obtain such job for the person who's PhD was based on structural biology > (experimentalist) or alternatively focused on molecular modeling and > bioinformatics ? > > Kind regards, > > Gleb > > 2014-09-16 23:36 GMT+04:00 Elaine Meng <meng(a)cgl.ucsf.edu>: > >> Dear Gleb, >> I really don't know the answer! I've never searched for such a position >> myself. I could only guess that you would try to search for "teaching" in >> addition to the keywords about molecular modeling and structural >> bioinformatics. >> >> For postdocs at least, most people are looking for research lab positions >> rather than teaching. In that case they identify research papers that >> describe the types of work that they want to do, then contact the labs of >> the authors about possible postdoc opportunities. >> >> The only other idea I have is to try to figure out (by online searching) >> what institutions offer classes in chemistry and biology that include >> structures/modeling, then see if they have openings for instructors. >> >> I'm sorry, I don't think these are very bright ideas, or anything that >> you wouldn't have thought of yourself already. >> Best, >> Elaine >> ---------- >> Elaine C. Meng, Ph.D. >> UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab >> Department of Pharmaceutical Chemistry >> University of California, San Francisco >> >> >> On Sep 16, 2014, at 12:09 PM, James Starlight <jmsstarlight(a)gmail.com> >> wrote: >> >> > Hi Elaine, >> > >> > thank you for the suggestions again! By that time I've noticed that to >> find structural bioinformatics position is much complicated than to find >> positions in fields of theoretical biophysics, computational biology or >> even genome bioinformatics. BTW according to your experience what keywords >> might be to seek position focused rather not to the research but to make >> some teaching practice, workshops and tutorials (focused on structural >> bioinformatics and modeling)? >> > >> > Kind regards, >> > >> > Gleb >> > >> > 2014-09-10 2:52 GMT+04:00 Elaine Meng <meng(a)cgl.ucsf.edu>: >> > Glad it was useful! I don't know if there is a specific name other >> than "structural bioinformatics," but especially now that more and more >> structures are known (in combination with perhaps too many sequences!), it >> should be a fruitful and interesting area of research. >> > Best, >> > Elaine >> > >> > On Sep 6, 2014, at 12:00 AM, James Starlight <jmsstarlight(a)gmail.com> >> wrote: >> > >> > > Hi Elaine, >> > > >> > > thank you very much It was really useful for me! I plan to look for >> the post-doc for myself on next year switching from the modeling and >> theoretical chemistry to structural bioinformatics coupled with the >> phylogenetic analysis (I don't know yet precise name of this discipline in >> the computational biology) so It will be very helpful! >> > > >> > > All the best, >> > > >> > > James >> > > >> > > >> > > 2014-09-05 20:59 GMT+04:00 Elaine Meng <meng(a)cgl.ucsf.edu>: >> > > HI James, >> > > Sorry, Chimera does not do evolutionary trace calculations. I would >> definitely have mentioned it if it did! In Chimera, if you input a tree >> along with your alignment, you can click a node on the tree and easily >> extract only the sequences for that node, but there is nothing to compare >> the residues from one set of sequences with those from another set of >> sequences, other than looking at the separate alignment windows yourself. >> Also, Chimera cannot create the tree, it must be read in from a file. >> > > < >> http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/multalignviewer/f… >> > >> > > … see the section on Trees: >> > > < >> http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/multalignviewer/m… >> > >> > > … example image of tree+alignment in Chimera: >> > > < >> http://www.rbvi.ucsf.edu/chimera/data/tutorials/systems/redoxin/ConSurf-1hd… >> > >> > > >> > > Although I’m still very interested in GPCRs, I have not actively >> worked on them for >10 years, so I’m not the best person to ask for >> current information. I know there is a GPCRdb, but I don’t know if it has >> been kept up to date. You could try googling or pubmed-searching for “gpcr >> alignments” or similar terms. >> > > >> > > Two ideas for evolutionary trace: >> > > >> > > (1) The Lichtarge group has an evolutionary trace server. >> > > <http://mammoth.bcm.tmc.edu/ETserver.html> >> > > >> > > At first I thought you could only put in a PDB ID and not have any >> control over what sequences are used (which might not be useful for your >> research), but then I noticed a “GPCRs” link on the left-hand side. Click >> that and it lets you choose specific GPCR subsets, which sounds exactly >> like the kind of calculation you wanted. I don’t know if it includes your >> specific groups of interest, however, and I don’t see a way to use your >> own alignments. >> > > <http://mammoth.bcm.tmc.edu/gpcr/diff_GPCRA.html> >> > > >> > > (2) JEvTrace, a Java implementation of evolutionary trace. >> > > <http://compbio.berkeley.edu/people/marcin/jevtrace/> >> > > >> > > I have one correction to that page. It says you can show results >> using the MSF Viewer tool in Chimera, which no longer exists. You can >> still use Chimera, just the Multalign Viewer tool instead (Multalign Viewer >> menu: "File… Load SCF/Seqsel File” will open the file from JEvTrace). I’ll >> email the author and tell him to update that information. >> > > >> > > Those are all my ideas. If neither helps you, you may have to >> continue searching for programs or other tools and instructions on how to >> do the steps of the analysis yourself. >> > > I hope this helps, >> > > Elaine >> > > ----- >> > > Elaine C. Meng, Ph.D. >> > > UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab >> > > Department of Pharmaceutical Chemistry >> > > University of California, San Francisco >> > > >> > > On Sep 4, 2014, at 11:39 PM, James Starlight <jmsstarlight(a)gmail.com> >> wrote: >> > > >> > > > Elaine, >> > > > >> > > > onequestion about your 2003 GPCRs study: in this paper you've used >> the method called differential evolution tracing to detect >> functionally-relevant amino acids for rhodopsin only (substration of the >> conservative residues found in rhodopsin from those found in whole set of >> A-class GPCRs). I wounder if there any possibility for this method in >> Chimera's mutalign (in case where I have big alignment with thesequences of >> all olfactory receptors) to substract residues found in one philogenetic >> branch (corresponded to specified sub-class or group of those receptors) >> from the residues common to all olfactory receptors or (ii) substract >> residues common for the all olfactory receptors from those common to all >> A-class GPCRs? BTW do you know open-access data-bases consisted of the >> evolutional (alignments) information to the GPCRs? it's intresting to >> compare my alignment with some references. >> > > > >> > > > Thanks for help, >> > > > >> > > > James >> > > >> > > >> > > _______________________________________________ >> > > Chimera-users mailing list >> > > Chimera-users(a)cgl.ucsf.edu >> > > http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users >> > >> > >> >> >

2 1

Remove shapes programmatically
by jiserte＠unq.edu.ar 08 Oct '14

08 Oct '14

Hello. I'm having a problem working with shapes in chimera. I'm adding shapes with a script using commands like: shape tube #:1@CA#:100@CA radius 0.1 I want to remove some of the shapes later in the script, however i can not find the proper way to do it. I know is posible to do it using the GUI (picking the shape with control key and then "Actions>Surfce>Hide" in the menu bar), but i dont know how to do the same with the command line. Also, i can not find the way to manipulate existing shapes (increase radius, change color, etc). There is a way to delele, hide or manipualte shapes? Thank you all. Javier Iserte PhD Fundación Instituto Leloir Buenos Aires, Argentina.

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Re: [Chimera-users] measure symmetry
by Tom Goddard 08 Oct '14

08 Oct '14

Hi Reggie, I used the following Chimera commands to create an icosahedral cage for virus capsid 2xyz and density map for full capsid, image attached. Tom open 2xyz rainbow chain sym #0 surf true # Used Tools / Higher-Order Structure / Icosahedron Surface to figure out orientation is n25r (no sym on x, 2-fold on y, 5-fold on z, with extra rotation). shape icos radius 400 orient n25r lattice 2,1 color blue linewidth 5 molmap #0 10 sym i,n25r On Oct 8, 2014, at 10:40 AM, Reginald McNulty wrote: > Dear Tom, > > I’ve imported a virus capsid shell pdb 2xyz to chimera. I want to measure the symmetry and make a cage based on that symmetry. Molmap seems to only produce a map of the asymmetric unit, not the entire capsid. Any thoughts? > I’m currently following directions that are here: http://www.cgl.ucsf.edu/chimera/videodoc/IcosWedge/index.html > > All the best, > -Reggie > > -- > Reginald McNulty, Ph.D. > Postdoctoral Research Associate > The Scripps Research Institute > Johnson Lab > Department of Integrative Structural and Computational Biology > 10550, N. Torrey Pines Road, MB-31 > La Jolla, California 92037 > > > > > >

1 0

help
by JESSE JAYNES 06 Oct '14

06 Oct '14

I am a long time user of Chimra and greatly appreciate the software. I am also a professor at Tuskegee university and I use it in the classroom. I am Mac user. I have a question. How can I model an all D-form of a 10 amino acid peptide and generate its pdb? Thank you! Jesse M. Jaynes

2 2

delete water residues: mangled atom specifier
by George Tzotzos 06 Oct '14

06 Oct '14

I’m running an amber trajectory and in particular snapshots I’d like to delete all water molecules but one. If I do del :WAT !1355.water I get a “mangled atom specifier”. Obviously I got the wrong syntax. Your help will be much appreciated Regards George

2 2

Question about RMSD calculation of MatchMaker
by Matthias Fellner 03 Oct '14

03 Oct '14

Good day I am a PhD student at the University of Otago New Zealand. First I would like to thank you for this very useful software, I use it for all my protein crystallography pictures and a lot of analysis as well, I will use a citation for sure when I publish using your software. A current analysis of mine involves a crystal structure that has 4 chains in the asymmetric unit. They chains are very similar when aligned and I would like to have a statistic to show this. I assume the RMSD is the way to go. So I saved each chain as its own pdb, loaded them in Chimera and used your MatchMaker to align chain B,C and D to chain A (randomly chosen because of notation of chains). The chains have an identical amino acid sequence (~200 residues), I just build 1-5 residues more or less at each end of the chain but otherwise they should all be the same. Now the reply log gives out the RMSD and the number is under 1Å as I expected and I can quote that. But my question would be why did it use a different numbers of atom pairs for the different chains (191 or 188 or 193) and which atom pairs are those. I assume it picks one atom from the main chain of each residue and the different number comes from the difference residue number at the end of the chains. I searched through your help files and with google through your board but could not find the answer to what atoms are paired and if you can change the pair for example to include all atoms of the mainchain or even all atoms all together. Sorry for the long question but I wanted to give all the details, attached also the (default) options I had for the MatchMaker and the reply log. In addition a small question which I guess wont be possible - is there any way to also align water molecules adjacent to the chains although all water molecules are saved in chain S together? Thank you Matthias [cid:image001.png@01CFDE66.FDAB5BD0] Matchmaker chainA.pdb, chain A (#0) with chainD.pdb, chain D (#3), sequence alignment score = 999.7 with these parameters: chain pairing: bb Needleman-Wunsch using BLOSUM-62 ss fraction: 0.3 gap open (HH/SS/other) 18/18/6, extend 1 ss matrix: (O, S): -6 (H, O): -6 (H, H): 6 (S, S): 6 (H, S): -9 (O, O): 4 iteration cutoff: 2 RMSD between 191 atom pairs is 0.506 angstroms Matchmaker chainA.pdb, chain A (#0) with chainC.pdb, chain C (#2), sequence alignment score = 999.1 with these parameters: chain pairing: bb Needleman-Wunsch using BLOSUM-62 ss fraction: 0.3 gap open (HH/SS/other) 18/18/6, extend 1 ss matrix: (O, S): -6 (H, O): -6 (H, H): 6 (S, S): 6 (H, S): -9 (O, O): 4 iteration cutoff: 2 RMSD between 188 atom pairs is 0.551 angstroms Matchmaker chainA.pdb, chain A (#0) with chainB.pdb, chain B (#1), sequence alignment score = 987.2 with these parameters: chain pairing: bb Needleman-Wunsch using BLOSUM-62 ss fraction: 0.3 gap open (HH/SS/other) 18/18/6, extend 1 ss matrix: (O, S): -6 (H, O): -6 (H, H): 6 (S, S): 6 (H, S): -9 (O, O): 4 iteration cutoff: 2 RMSD between 193 atom pairs is 0.336 angstroms

2 1

Reg: Peptide Dimer
by Amit Jaiswal 30 Sep '14

30 Sep '14

Hi, I would like to know if is it possible to prepare peptide dimer In Chimera. If yes, how and if no what are the possible ways to prepare it? Thanks in advance. With kind regards, Amit Jaiswal -- *Yours Sincerely,* *~~~~~~~~~~~~~~~~~~~~~~~~**~~~* *Amit Jaiswal,* *A.T. Road, Tarajan,* *Jorhat - 785001,* *Assam.-------------------------------------------* *Centre for Bioinformatics,Pondicherry Central University,* *Pondicherry - 605014,* *Pondicherry. * *~~~~~~~~~~~~~~~~~~~~~~~~**~~~**~*

2 1

Proposal to add ability to load CATH domains in Chimera
by Tony Lewis 30 Sep '14

30 Sep '14

Dear Chimera people, Many thanks to all Chimera contributors. Please may I propose an addition to allow users to access our CATH domains in the same way that they can currently access SCOP domains ( https://www.cgl.ucsf.edu/chimera/docs/UsersGuide/scop.html )? PDBs for CATH domains can be loaded from URI's of the form: http://data.cathdb.info/latest_release/pdb/1cukA01 For information, CATH domain IDs contain 7 digits: - 1-4 : (eg 1cuk ) : PDB code - 5 : (eg A ) : chain code - 6-7 : (eg 01 ) : 2-digit domain number ( '00' for whole chain domains ) We here at CATH would be very happy to provide any other information required to implement this. Many thanks for your help. Kind regards, Tony Dr Tony Lewis Orengo Group UCL

2 3

Regarding organic molecule minimization
by Satheesh G 29 Sep '14

29 Sep '14

Dear Sir, The azo compounds (organic molecule) minimization using Chimera software giving linear form (R-N=N-R to R-N=N-R (180 degrees bong angle between R-N=N instead R-N=N- 120 degrees). Which is not true. I have used the gasteiger and amber ff12sb force field. Please suggest me to solve this problem. Thanking you. Satheesh. [image: Inline image 1]

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Select next residue
by Tom Goddard 29 Sep '14

29 Sep '14

Hi Yanyan, I added three new keyboard shortcuts. “rn” selects the next residue after the currently selected one and the currently selected one gets unselected — basically it just moves the selection down by one residue. This applies even if a several residues are selected, the whole selection just gets moved down the chain by one position. “rp” selects the previous residue, and “ri” selects all residues between two currently selected residues. These should help you move the selection along in a quick way. Chimera keyboard shortcuts are not enabled by default. To enable them use the Chimera command “ac” (stands for accelerators) or use menu entry Tools / General Controls / Keyboard Shortcuts and click “Enable keyboard shortcuts”. If you use that menu entry then it will be remembered and shortcuts will be enabled when you start Chimera the next time. Shortcuts are all 2 letters and you don’t hit return after typing one. To get back to typing a command instead of a shortcut use the shortcut “cl” (command line). Here’s the list of shortcuts from the Chimera documentation. http://plato.cgl.ucsf.edu/chimera/docs/ContributedSoftware/accelerators/ali… The new ones will be in tomorrow’s daily build (dated Sept 27, 2014). Tom On Sep 26, 2014, at 7:10 AM, Zhao, Yanyan wrote: > Hi, Tom. > > Thank you so much for the chimera lecture yesterday. It is very helpful. > I'm Yanyan from Baylor college of Medicine and is a rotation student in Wah's lab now. I'm using this software now. But I have a problem finding the keyboard shortcuts for selecting residues. I want to select residue one by one along the whole chain. But Ctl+left mouse click is a pain when dealing wit so many residues. Is there any shortcuts that I don't need to click the mouse and still can flow through the chain? > > Thanks. > > Best regards, > Yanyan

2 1

running chimera on FC20
by David Roberts 29 Sep '14

29 Sep '14

Hi all, I just did a clean install of FC20 on an AMD dual core system. I opted for the 32 bit version, as these workstations are used for multiple things (and I find that it’s just easier most of the time, though 64 bit may be where I need to go eventually). I installed Chimera Version 1.9, Build 39798 on Fedora FC20. When running chimera, my computer constantly freezes. Obviously I’m missing something. I’m not doing anything fancy - I use Zalman monitors connected to generic video cards. I can run coot fine - I don’t know about ccp4i (it seems to run, but I haven’t challenged it in any way). As long as Chimera is not running, my computer runs nicely. I have flash/etc… working fine. Any thoughts on where I should start here? This happens on 3 separate systems (that are essentially the same, but not identical clones). I’m assuming I missed something obvious in the install. Thanks Dave

2 1

How to load PDB data inline in Chimera script/command files
by Tony Lewis 29 Sep '14

29 Sep '14

Dear Chimera people, Many thanks to all Chimera contributors. Please can anyone tell me if there's a way to include PDB data *inline* in Chimera script / command / Chimerax files? PyMOL's read_pdbstr() command loads PDB data from an inline string, which means one file can contain both the structural data and the associated commands. That's rather convenient. I would much appreciate any help on how to do the same with Chimera. Apologies if the answer is obvious. Many thanks and kind regards, Tony Dr Tony Lewis Orengo Group UCL

2 1

Angle
by Jian Guan 25 Sep '14

25 Sep '14

Hi All, I made two axes for two molecule, and want to measure the angle between them. Let's say, #1 and #2 are the two axes. I used command line of "angle #1 #2" to do that. Question: What is the default angle measurement? The #1 rotate clockwise or anti-clockwise to reach #2? Thanks, Jian

2 4

Castp volume and surface area
by Felipe Vasquez 24 Sep '14

24 Sep '14

Hi, I am using CASTp plugin from Chimera in order to calculate both the volume and surface area of a specific pocket. I noticed that the 'mouth' atoms can be excluded from the visualization, and even the surface area is reported separately for both the pocket and the mouths by CASTp. However, there is only one reported volume. Is that volume considering both the pocket and mouth atoms to make just one general calculation? In addition, where can I find more info about the criteria to define a pocket's mouth? Thanks in advance for your help. Best regards, *Andrés Felipe Vásquez J., BSc, MSc.* Grupo de Fisiología Molecular Subdirección de Investigación Científica y Tecnológica Dirección de Investigación en Salud Pública Instituto Nacional de Salud Avenida calle 26 No. 51-20 - Zona 6 CAN +57 (1) 2207700 ext. 1419 Bogotá, D.C., Colombia

2 1

opening a .dx format file as a volume file?
by David A Case 24 Sep '14

24 Sep '14

Hi: Is there a way for chimera to open a .dx file, but to treat the data as volume (density) data, rather than as an electrostatic potential? That is, I'd like the data in the .dx file to be rendered by the Volume Viewer, as if I had opened a CNS/XPLOR or CCP4 map file. Or, do you know of programs that will convert these file formats? (I've written one of my own, but am looking for confirmation that my code is actually correct, and doesn't have some off-by-one grid point or other mistake.) ....thanks!....dave case

2 1

code or psuedo code for unit cell packing
by Bennion, Brian 24 Sep '14

24 Sep '14

Hello I found the unit cell gui to be very useful recently. However I am curious about how the "pack into unit cell" option works. What information in the pdb header is used to translate/rotate a set of monomers each in an individual unit cell and pack them back into the "original cell". Thanks for any help Brian

3 5

soft roll off edges with Zone masks
by Adam Frost 23 Sep '14

23 Sep '14

hi Chimera users We have determined a pseudo-atomic resolution cryoEM density of a helical co-polymer (two unique chains for the repeating hetero-dimer). We would like to compute map-versus-model FSC curves for each of the unique chains. We'd like to use the Zone tool to mask out the relevant density per chain within ~3A or so of the atoms in our atomic model, but we would like the edges of this mask to be appropriately "soft" (whereas right now zone masking appears to employ a hard edge). has anyone already solved this problem? ~Adam

2 1

Swapping aminoacid to a non-standard residue
by Rui Almeida 23 Sep '14

23 Sep '14

Hello all I am trying to change one aminoacid on a PDB file to a nonstandard residue: TYR to nitrotyroine (PDB ligand code: NIY). I tried modifying the structure of the existing aminoacid in the coordinate file to include an NO2 group in the meta position (Structure Editing --> Build Structure --> Modify Structure...), but ANTECHAMBER cannot assign the correct charges afterwards. Command "swapaa" was also ineffective. Is there anyway to modify the residue and assign the correct charges? Thank you in advance, Rui Almeida. -- Rui Almeida Ph.D., Biochemistry REQUIMTE/CQFB - BioInorganic Chemistry Lab Dep. Quimica, Faculdade de Ciencias e Tecnologia, UNL 2829-516 Caparica, PORTUGAL E-mail: rui.almeida(a)fct.unl.pt

2 1

Find Clashes/Contact (or FindHBond) after splitting chains?
by Mark Girvin 19 Sep '14

19 Sep '14

(Apologies if this arrives twice - on rechecking it, the email address that I tried first looked wrong) Hello, A student in our Biochem class (we have them use Chimera, and tell them that this choice is because it is such a well-done program, and has such active support from the developers and mailing list -- thank you all!) was trying to use Tools->Structure Analysis->Find Contacts/Clashes (and FindHBonds, with the same problem) after running split to simplify displaying and hiding the 14 chains in the coordinate file of the oligomer (1avo) that he was working on. Selecting the residues in one chain (now one model), designating them as the first set within Find Clash/Contacts, checking against all other atoms, choosing "contacts" and applying (Find Contacts) gives no contacts (0 contacts on Reply log). But if run before splitting (selecting chain A and running Find Clash/Contact with the same settings) finds many contacts. The same holds true when using FindHBond - works pre-split, but not post-split. I was wondering whether we were doing something wrong, or if this is the expected behaviour? Thanks, - Mark (our work-around was to delete different subsets of chains and save the resulting coordinates as "HeteroDimerDimer.pdb" & "HeteroDimer.pdb" and then work with those, which went fine) - Mark

2 2

Hardware requirements
by Rick Roberts 19 Sep '14

19 Sep '14

Hello, We are on boarding a Physician that will be using Chimera. What are the hardware requirements (processor, video card, memory, etc.) Thanks in advance. Rick Roberts Children's Hospital Los Angeles Pathology and Laboratory Medicine Phone: 323-361-5836 Fax: 323-361-8004 Cell: 818-415-6085

2 1

Find Clashes/Contact (or FindHBond) after splitting chains?
by Mark Girvin 19 Sep '14

19 Sep '14

Hello, A student in our Biochem class (we have them use Chimera, and tell them that this choice is because it is such a well-done program, and has such active support from the developers and mailing list -- thank you all!) was trying to use Tools->Structure Analysis->Find Contacts/Clashes (and FindHBonds, with the same problem) after running split to simplify displaying and hiding the 14 chains in the coordinate file of the oligomer (1avo) that he was working on. Selecting the residues in one chain (now one model), designating them as the first set within Find Clash/Contacts, checking against all other atoms, choosing "contacts" and applying (Find Contacts) gives no contacts (0 contacts on Reply log). But if run before splitting (selecting chain A and running Find Clash/Contact with the same settings) finds many contacts. The same holds true when using FindHBond - works pre-split, but not post-split. I was wondering whether we were doing something wrong, or if this is the expected behaviour? Thanks, - Mark (our work-around was to delete different subsets of chains and save the resulting coordinates as "HeteroDimerDimer.pdb" & "HeteroDimer.pdb" and then work with those, which went fine)

1 0

New Residue-interaction network MD movie plugin
by rswett＠chem.wayne.edu 19 Sep '14

19 Sep '14

Hey all, I'm trying to visualize an RIN from a dynamics run using the new addition to the Trajectory tools. Cytoscape isn't playing nice with launching chimera, so I was wondering how difficult it would be to save the calculated network to load independently in cytoscape? Currently the calculation runs just fine, but I can't save the output. Is there a command line way to do it? Any other suggestions? Rebecca

3 3

use Chimplug
by Pande, Ajay K 19 Sep '14

19 Sep '14

How would one use Chimplug plug-in in Chimera? I would like to generate CRD/PSF files for the ligand for use in CHARM. Thanks Ajay

3 2

open amber trajectory error
by Renato Freitas 19 Sep '14

19 Sep '14

I am trying to open a zipped amber trajectory with chimera but I am getting the following error: ################################# Traceback (most recent call last): File "/home/disk0/rfreitas/softwares/chimera/share/chimera/triggerSet.py", line 83, in invoke self._funcData, triggerData) File "/home/disk0/rfreitas/softwares/chimera/share/DBPuppet/__init__.py", line 329, in portOnTop self.remove_webinfo(self.listen_port) File "/home/disk0/rfreitas/softwares/chimera/share/DBPuppet/__init__.py", line 369, in remove_webinfo with lock: File "/home/disk0/rfreitas/softwares/chimera/lib/python2.7/site-packages/filelock.py", line 120, in __enter__ self.acquire() File "/home/disk0/rfreitas/softwares/chimera/lib/python2.7/site-packages/filelock.py", line 32, in acquire self._createFile() File "/home/disk0/rfreitas/softwares/chimera/lib/python2.7/site-packages/filelock.py", line 86, in _createFile os.write(self.fd, "%d\n" % os.getpid()) OSError: [Errno 28] No space left on device Error processing trigger "Focus In": OSError: [Errno 28] No space left on device File "/home/disk0/rfreitas/softwares/chimera/lib/python2.7/site-packages/filelock.py", line 86, in _createFile os.write(self.fd, "%d\n" % os.getpid()) See reply log for Python traceback. ################################################ if I unzip the file, I can open it without problems. Since I have many files to look and they are very big (> 300 MB zipped) I don't want to unzip every file whenever I have to look at the trajectory. Any help will be appreciated. thanks, Renato

2 2

reading .sd files
by Fabian Glaser 16 Sep '14

16 Sep '14

Hi, I have tried to read .sd files with docking ligands, without success. Is there a way to ready results of docking in .sd format in Chimera? Thanks a lot, Fabian _______________________________ Fabian Glaser, PhD Head of the Structural Bioinformatics section Bioinformatics Knowledge Unit - BKU The Lorry I. Lokey Interdisciplinary Center for Life Sciences and Engineering Technion - Israel Institute of Technology Haifa 32000, ISRAEL fglaser(a)technion.ac.il Tel: +972 4 8293701 Fax: +972 4 8225153

3 2

use of software to model structure
by Elsa Marquez 15 Sep '14

15 Sep '14

Hi there! I'd like to create a model of a protein that hasn't been crystallized yet, there are a few other highly homologous proteins that have been crystallized and are at PDB, so I was wondering if CHIMERA, or if you know about other software, can be used to model the unknown protein structure based on the known structure of homologous proteins. Thank you, I really appreciate your help! Elsa Marquez

2 2

Trajectory B-factors
by George Tzotzos 15 Sep '14

15 Sep '14

Hi everybody, Is there a way to calculate the B-factors of the backbone atoms of protein residues in a MD trajectory? I checked earlier correspondence and saw that it can be done in Chimera with pdb structures. Many thanks in advance for any suggestions Regards George

3 2

Feature request: parallel MatchMaker?
by Jonathan Sheehan 11 Sep '14

11 Sep '14

Hi- I'm a huge fan of Chimera, and I frequently need to superimpose a dozen or more comparative models onto a template protein using MatchMaker. At present, one cannot even rotate the view until all matches have completed, which can take a few minutes on a single core. Based on old messages[1], it sounds like you might be "interested in allowing use of multiple cores for specific compute intensive tasks," and this seems to me like a good candidate. This use case involves many matches, which I think are completely independent of one another. Also, these models have identical length and sequence, so the runtimes should be fairly close to one another (although that wouldn't necessarily be true in the general case). I'm sure that adding multi-threading to a tool is not trivial, but it seems as though this feature might have a high "bang for the buck" on today's multicore machines. Thanks for considering it, -Jonathan 1. E.g. http://www.cgl.ucsf.edu/pipermail/chimera-users/2011-January/005901.html -- Jonathan Sheehan, Ph.D. Computational Structural Biology Vanderbilt Univ. Ctr. for Struct. Biol. 5137 MRB3, 465 21st Avenue S. Nashville, TN 37232-8755 615-936-2516

3 4

Origin issue of mrc file from chimera to pymol
by Kai Zhang 11 Sep '14

11 Sep '14

Dear Chimera users, I found the pdb files fitted to mrc maps in Chimera do not always fit the same map opened by Pymol. It seems that the origins are calculated differently between Chimera and Pymol. I can easily handle an entire map of mrc file. But if the map has been cut, it's very difficult to find out what really needs to be modified to fit both chimera and pymol. Does anyone know an easy way to deal with this issue? Best wishes Kai

3 3

Analysis of the multiple alignments + structures
by James Starlight 06 Sep '14

06 Sep '14

Dear Chimera Users! I'd like to perform analysis of the set of the sequences (presented in the FASTA multiple-alignment file) together with the some (not all) X-ray structures available for several of the sequences presented in its database to detect conservative motifs (from sequence) and make conclusions about its functional importance (based on the analysis of the Xray data) to make conclusions between conservation of sequence and it's functional relevance. Could you provide me with the some useful Chimera plugging as well as for some tutorials Kind regards, James

3 14

Models views
by James Starlight 03 Sep '14

03 Sep '14

Dear Chimera users! I'd like to find possible option in Chimera for splitting 2 alligned models into 2 adjacent (e.g on left and right parts of the screen) object view (like what in Pymol 'Grid objects' is actually do). I didn't find this in the tutorials and will be very thankful if someone suggest me with this together with the list of some other commands usefull for the analysis of the aligned structures. Kind regards, Gleb

2 2

Measuring dihedral angles using chimera
by Aswani Kumar Kancherla 02 Sep '14

02 Sep '14

Hello Chimera Users, I have recently installed chimera version 1.9 in Linux OpenSuSe 11.4 and am trying to get acquainted with its features. I am trying to measure dihedral angles (specifically the angle chiSS defined by Cb-Sg-Sg'-Cb' about disulfide bonds) for a list of pdb files containing NMR structure ensembles. I was trying to do this using a script (kindly given by a friend and pasted below) to which I can pass the coordinates of the four atoms and get the measured values for the "reply log" information. I need to put the files in a directory called pdb_files, open chimera and call the script and retrieve information from the "reply log". However, there is a problem: Since the coordinates of (Cb,Sg, etc ) will be different for each of the ensemble (since each ensemble is structure of a different molecule), I need to pass the coordinates dynamically for each pdbid. I have found from Chimera User group archives that reply log can be saved using a function. http://plato.cgl.ucsf.edu/pipermail/chimera-users/2008-October/003184.html So that should solve one issue. I can save the reply log and parse it later. What is the best way to measure specific dihedral angles from multiple pdb files ? Is it possible to invoke chimera in tty mode and make it execute functions? In that case, I could probably write a shell script to invoke chimera once for each pdb and ask it to execute python script having appropriate atom coordinates. I apologize for slightly long an e-mail. Any hints or directions to enable me figure out how to get this done efficiently in chimera will be of great help to me. with regards, Aswani *script:* *================================================================* *import os* *import Matrix* *from chimera import openModels, selection, runCommand* *#angle #0:resno@CB :resno@SG :resno@SG :resno@CB 34.6289* *# Directory containing PDB files* *directory = 'pdb_files'* *# Get paths to all files in the specfied directory * *paths = [os.path.join(directory,f) for f in os.listdir(directory) if f.endswith('.pdb')]* *for pdbfilename in paths:* * filename = pdbfilename.split("/")[1]* * openModels.open(pdbfilename, baseId = 0) # Open as model #2* * runCommand('angle #0:863@CB :980@SG :1130@SG :1235@CB') # calculate torsion angle* * runCommand('close #0') # close molecule and map* *=================================================================* -- K.Aswani Kumar Graduate Student Molecular Biophysics Unit Indian Institute of Science Bangalore-560012 Karnataka, India.

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Small molecules and orbitals/ESP's
by Kenward Vaughan 30 Aug '14

30 Aug '14

Hi all, I am searching for a way to show small molecules with orbitals and potential surfaces from their associated QM calculations, in stereos display using our planned 3D vision setups. Cross eye works well for some in a class, but mant students simply never get it. It doesn't appear that any small molecule viewers are out there with such capability. Is there some way to pull such information into Chimera to do this? Kenward -- In a completely rational society, the best of us would aspire to be *teachers* and the rest of us would have to settle for something less, because passing civilization along from one generation to the next ought to be the highest honor and the highest responsibility anyone could have. - Lee Iacocca

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Question: how can I render pseudobonds visibly when saving as Chimera-highres-image]
by Dietlind Gerloff 29 Aug '14

29 Aug '14

Dear Elaine and Tom and other Chimera-developers/maintainers, I cannot tell you how much I admire (and appreciate) what you have done with Chimera !!! I am just getting the last touches on a collaborative paper with colleagues from the University of Edinburgh and I used Chimera for much of the modelling of a large protein (Condensin) and for lovely images as well. We'll make sure we give you proper credit! One thing I'm having problems with - I am now trying to save image in high-resolution (600dpi) that show pseudo bonds Each pseudobond highlights a distance constraint, i.e. they are drawn by the distance function/monitor and are visible beautifully on the screen. However, when I save (as .png, .jpg or whatnot) the pseudo bond doesn't scale, i.e. becomes so thin compared to the regular bonds that it cannot be seen unless one zooms in like mad. Doesn't matter how wide I ask the pseudo bond to be on the display. Is there a way to change the preferences for how (thick) pseudo- bonds are rendered when I save an image using Chimera-rendering? Sorry to bug you so close to Labor Day weekend but if you had a quick answer (even if there isn't) that would help. Alternatively I could maybe draw lines/bonds but it seems such a pity since the pseudobonds are so beautifully telling the story on my screen ... in the worst case, we'll screen shot for now, of course ;-) Cheers and again I have become a Chimera fan recently and I am now telling students and coworkers to use it instead of PyMOL - also because of the amazing tutorials and help pages. W-O-W !!! Dietlind *Elaine, in case you don't remember me - I was a postdoc with Fred Cohen when you were in Tack's lab in the Midas days a long long time ago :-) -------------------------------------------- Dietlind L Gerloff, PhD Senior Fellow Foundation for Applied Molecular Evolution (FfAME) Gainesville, FL 32604 email: dgerloff(a)ffame.org --------------------------------------------

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scan and minimization of dihedral angle
by Milo Westler 28 Aug '14

28 Aug '14

Hi, I want to to a potential energy scan of a dihedral (of a small organic molecule) by setting a dihedral angle, fixing those atoms involved, and doing a minimization. Then incrementing the angle and repeating. I can currently do all of this by using the gui (set torsion angle in build_structure,minimize with selected atoms fixed , then save and edit the final energies for each angle in reply log). I'm sure that this can be done with python. I am wondering if there is an available script to do this all. As input I would have a set of torsion angles and as output I would like a table of angle and energy. -- -- Milo =================================================== National Magnetic Resonance Facility at Madison An NIH-Supported Resource Center W. Milo Westler, Ph.D. NMRFAM Director Senior Scientist and Adjunct Professor Department of Biochemistry University of Wisconsin-Madison DeLuca Biochemistry Laboratories 433 Babcock Drive Rm B160D Madison, WI USA 53706-1544 EMAIL: milo(a)nmrfam.wisc.edu PHONE: (608)-263-9599 FAX: (608)-263-1722 ======================================================================= ========

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Re: [Chimera-users] Edge visualisation
by Tom Goddard 28 Aug '14

28 Aug '14

Hi Petr, You are right about the Measure and Colors Blobs tool — the “Show principle axis box” option shows a box aligned with the moment of inertia principle axes. I was mistaken in my previous email. The behavior is described in the documentation (almost every Chimera feature is described in great detail) — just press the Help button on the Measure and Color Blobs dialog to see: "Show principal axes box [color well] - whether to show a bounding box in the specified color (default green) for each subsequently picked blob. A blob's bounding box is aligned with its principal axes of inertia, calculated assuming a constant mass per unit surface area.” The Laplacian filtering is again described in the documentation. If you use the Volume Filter dialog press the Help button to see the documentation, or if you use the “vop laplacian” command you can see the documentation with command “help vop”. Anyways here’s what the docs say: "Laplacian filtering. The Laplacian operation is a sum of second derivatives. Laplacian filtering is useful for edge detection but amplifies noise, so it may be necessary to perform smoothing such as Gaussian filtering beforehand. Finite differences v(i-1)-2*v(i)+v(i+1) along each axis are used, and voxels at the edge of the box are set to zero.” You referred in your email to “second derivatives” and comparing them to zero. I thought you meant the six independent second derivatives that make up the Hessian. I guess meant the Laplacian (sum of second derivatives along x, along y, and along z. When you run Laplacian or Gaussian filtering or any other map filter in Chimera it makes a new copy of the map. Chimera does not save maps in session files. So if you want that Laplacian map to appear in the session file you need to save the map to its own file before saving the session. You do this with the Volume Viewer dialog menu File / Save Map As…. This is a pain, and some day we will allow the option to save the maps in the session file (even though they can be very large). The session also does not save information about how to recalculate your Laplacian map, so you have to save that map separately for sessions to restore it. Tom On Aug 28, 2014, at 1:08 AM, Petr Brazda wrote: > Hello Tom, > > Thank you for your answers and comments. I will try to work on this evaluation with my colleague, who is a skilled programmer. I think that measure and color blobs tool works differently (at least the boxes are not aligned with the data axes) - it finds the largest diameter and puts it as the "x axis", then finds the largest perpendicular diameter (y axis). I got two more questions: > > 1) how exactly is the laplacian calculated? I found this > https://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/volumeviewer/gaus…. If I understand it well it says that it calculates only non-mixed differences along x, y, and z axes (no diagonal direction, no dxdy...) and you write that the second derivative is in fact Hessian. Could you please precise this? > > 2) I wanted to save a session where I have overlapped density and its lapacian filter and I had to save this filter to be able to save the session. However, when I reopened the lapla. filtered data, there was only one bar in the histogram in the surface style, which makes the map unusable for me so now I have to do the filtering and subregion setting each time I begin with the analysis. Is there a possibility to add another bar into the histogram? > > Thank you, > > Petr > > -- > ________________________________________ > Petr Brazda > Institute of Physics of the ASCR, v.v.i. > Cukrovarnicka 10/112 > 16200 Prague 6 > Czech Republic

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Molecular Representations
by Jian Guan 28 Aug '14

28 Aug '14

Dear all, I have one question about the Molecular Representations. In chimera, molecule can be represented by ball and sphere. Sphere is with the VDW radius for atoms and stick bonds. What about the ball? What is the ball size? I tried to measure the distance between two molecules. I used command line of "measure distance #1 #2". It shows closest distance between two sets of atoms. When I made surface map for the same two molecules, I used the same command, it showed different number. I understand it is the distance of VDW. But what is the distance between atoms if I used PDB file instead of surface map? Which one is more reliable? Thanks, Jian

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Adding Hydrogens to Dexomethasone Misses 1 Atom
by BATUHAN KAV 27 Aug '14

27 Aug '14

Dear All, I am trying to add hydrogen atoms to dexomethasone ligand. In the original PDB file, there are two dexomethasone molecules. So, I create split them into two different PDB's. Then, I load them and use addH option. In one PDB (sil.pdb), everything works fine and all hydrogens are added successfully. However, in the other pdb (which I name as other.pdb), one hydrogen atom is missing. I will use these files for further parametrization in AMBER, so this is really important. I looked through the files over and over again but couldn't find any reason for this apparent difference. What am I missing? I also attach the files. Any help would be greatly appreciated. Cheers

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Re: [Chimera-users] Edge visualisation
by Tom Goddard 26 Aug '14

26 Aug '14

Hi Petr, Chimera doesn’t have much to help you measuring nano-crystals, since it is designed for molecular visualization. First I think the chance that Laplacian filtering will help you find edges of the crystals is small, because even a small amount of noise will be amplified greatly by the second derivative calculation. Perhaps by doing Gaussian smoothing first, followed by Laplacian filtering you can get something useful, but it depends on your data. The Chimera “measure and color blobs” tool only finds a bounding box aligned with the data set axes (density map x, y, and z axes). It has no capability to rotate to find the tightest box. There is a “measure intertia” command that computes the principle moment axes of atoms or a surface, which might find the nanocrystal axes if you could produce a surface of just one nano-crystal. But then there is no tool to use those axes and find the tightest box. Chimera does not have a specific capability to find a surface of a density map located where second derivative is near zero and first derivative is large. You could attempt to code something like this as a Python script for Chimera but I think it would be unlikely to work unless you have perfect data. I think you will get holes in the surface because of places where the second derivative becomes too large or first derivative too small. Your idea is good in theory, but I just don’t think it is likely to work with real noisy data. A few more comments about looking at a surface where the second derivative is near zero. If you want to show a range of second derivative values near zero, then that defines a volume, maybe a thin shell, not a surface. You can show that as bounding isosurfaces at the minimum and maximum allowed second derivative values. The second derivative is a 3x3 matrix (Hessian) so I think you probably are actually interested in the second derivative along the gradient direction being zero. Chimera doesn’t have any tool that analyzes the second derivative along the gradient direction. Your requests are all specialized and outside the realm of what Chimera is designed for. So Chimera doesn’t do these things, and quite likely no other software does either. To try your ideas will likely require that you do some programming. Tom On Aug 25, 2014, at 5:33 AM, Petr.Brazda(a)seznam.cz wrote: > Hello Tom, > > thank you for the answer. I have now a more complex question. I would like to extract dimensions and volumes of the nanocrystals embedded in a matrix. The problem is that the edges of the crystals are blurred and the density of the whole particle (crystals+matrix) increases slightly towards the centre of the particle. I started to use inflection point as a point where the crystal ends/begins. I found out that there is a Laplacian volume filter in Chimera, which would help me with the analysis. However, there are some problems. > > 1) Theoretically, the second derivative of the inflection point (where the particle ends/begins) is zero, but unfortunately it is also (close to) zero for the matrix and crystals in their "cores". Therefore, is it possible to visualize points, which have nearly zero (including the adjustment of the density (value) limits how far I want to go from zero) second derivative while having the first derivative "far" from zero (with possible adjustment of the density (value) "far")? I think that this filtering would show the real edges of the crystals (maybe there is a better option, as I said I am a complete newbie). > > 2) I would like to use "measure and color blops tool" for measuring the dimensions of the crystals. The crystals have developed crystal faces. Crystal structure is orthorhombic, so using three orthogonal axes for the measurement is optimal for me. However, the setting of the box axes is usually useless for me, because the axes of the box are not parallel with the crystallographic ones. Is it possible to rotate/adjust the box so it would measure the distances I want? Or is there an other option how to measure dimensions of a crystal in three orthogonal directions? > > 3) As I said in the beginning I also need the volume of the particles. Therefore, it would be optimal if Chimera would connect voxels with 2nd derivative about zero and 1st derivative far from zero and define them as the "surface" of the particle. Is such tool available in Chimera? There is a problem when the maximum in the 1st derivative is not so sharp and "noisy" so it is possible that there will be some range where the 2nd derivative will be close to zero/oscillate about zero so some "real minimum on the 2nd derivative" will be maybe necessary. > > Petr > > > ---------- Původní zpráva ---------- > Od: Tom Goddard <goddard(a)sonic.net> > Komu: Petr.Brazda(a)seznam.cz > Datum: 22. 8. 2014 17:58:21 > Předmět: Re: [Chimera-users] Intensity range shift > > > Yes, you can shift the density values with volume dialog menu Tools / Volume Filter, filter type Scale. Or you can do it with the volume operation command, e.g. "vop scale #0 shift 100” described in the manual > > http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/vop.html#scale > > Tom > > On Aug 22, 2014, at 5:22 AM, <Petr.Brazda(a)seznam.cz> <Petr.Brazda(a)seznam.cz> wrote: > > > Hello, > > > > I would like to ask whether there is a possibility in Chimera to shift the intensity range. I have tomography data, which range from -32000 to 10000 in intensity. A would like to gradually erase parts of the tomogram with volume eraser but it is not possible because the intesity range does not start at zero. It is not possible to do the job with subregion selection. Is there a way to shift the intensity range? > > > > Petr > > _______________________________________________ > > Chimera-users mailing list > > Chimera-users(a)cgl.ucsf.edu > > http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users

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Assigning pre-calculated attribute to B-factor column of pdb
by Oliver Clarke 26 Aug '14

26 Aug '14

Hi all, Is there an easy way to assign a pre-calculated attribute (for example, ramachandran probability) to the b-factor (or occupancy) column of a pdb file using chimera? I’d like to do this so I can color a pdb by ramachandran probability (or other custom attributes, e.g map-model correlation) and use it as a guide while rebuilding in Coot (which has options for coloring by b-factor or occupancy, but no other capacity for custom coloring of molecules). Best, Oliver.

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Export data to .xplor format
by Petr.Brazda＠seznam.cz 26 Aug '14

26 Aug '14

Hello, I would like to ask if it is possible to export the density map (.rec) to . xplor format. Petr

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