- Chimera-users - RBVI Mailing Lists

on chimera vop threshold
by Smith Lee 13 Feb '21

13 Feb '21

Dear All, I have a map (A.mrc). When I open it in chimera (the map should be #0), the Volume Viewer shows the Range is -0.618 to 1.63, the default Level is 0.175. With command "vop threshold #0 minimum 0.18 set 0" I got another map (let us call it B.mrc, should be #1), the Volume Viewer shows the Range is 0 to 1.63 (understandable, the maximum value is still 1.63 as in A.mrc, the minimum value is 0 as for all values not higher than 0.18 has been set to 0), the default Level is still 0.175. Immediately I run the command "vop threshold #1 maximum 0.17 set 1". Before I running the command, I guess all the density value should be either "0" or "1", because all the value lower than 0.18 has been set to "0", and all value higher than 0.17 has been set to "1". However after I run the command "vop threshold #1 maximum 0.17 set 1", I got another map (let us call it C.mrc, should be #2),the Volume Viewer shows the Range is 0 to 0.17 rather than 0 to 1, and wen I change the Level, the image of #2 changes correspondingly with the Level from 0 to 0.17. Here I would ask, why the command "vop threshold #1 maximum 0.17 set 1" did not lead to a map with all values greater than 0,17 as 1? How to get a map based on A.mrc so that all values less than 0.18 as 0 and all values greater than 0.17 as 1 (please tell me the specific method)? Is any significance for the obtained C.mrc with range from 0 to 0.17? I am looking forward to getting your reply. Smith

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Apple M1 chip
by 163 11 Feb '21

11 Feb '21

Hi There, Is there a version that is suitable for Apple M1 Mac? I found the old version is quite on M1 Mac. Thanks! ML

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Re: [Chimera-users] Creating new models from existing crystal structures
by Elaine Meng 08 Feb '21

08 Feb '21

You're welcome, I'm glad you figured it out! Elaine > On Feb 8, 2021, at 2:40 PM, Moradkhan, Tiglath A <tmoradkhan(a)csus.edu> wrote: > > Hi Elaine > Nevermind, I found my error. I tested the Join Model tool with 1AV1 which has four chains and I was able to correctly pick the correct C and N atoms to join residue segments from each chain. The select command that I had written originally wasn't right so it was picking the correct atoms to join. > Thanks for your help. > Best > Tiglath > > > On Feb 8, 2021, at 2:27 PM, Elaine Meng <meng(a)cgl.ucsf.edu> wrote: > > > > If the residue is already in a peptide bond, you can't add another peptide bond. You would have to delete the rest of the chain after 130 in one copy of the model and the rest of the chain before 131 in the other copy for it to make sense. > > > > Also, make sure that your "select" command is selecting exactly two atoms, 1 from each model. > > > > Elaine > > > >> On Feb 8, 2021, at 1:53 PM, Moradkhan, Tiglath A <tmoradkhan(a)csus.edu> wrote: > >> > >> Hi Elaine > >> > >> I've been using the biological assembly of 3R2P and I'm thinking that the reason why it's not working is because both chains are labeled A. I'm just following a paper where they're building a monomeric structure using the residue fragments but in their case the biological assembly of 3R2P is labeled as chain A and chain B. > >> From: Elaine Meng <meng(a)cgl.ucsf.edu> > >> Sent: Monday, February 8, 2021 1:01 PM > >> To: Moradkhan, Tiglath A <tmoradkhan(a)csus.edu> > >> Cc: chimera-users(a)cgl.ucsf.edu <chimera-users(a)cgl.ucsf.edu> > >> Subject: Re: [Chimera-users] Creating new models from existing crystal structures > >> > >> Hi Tiglath, > >> If you just opened 3r2p one time, you only have one model. Join works on bonding two separate models. Also it contains only chain A (there is no chain B in this structure) and residue 130 in chain A is already bonded to residue 131 in chain A. So I do not understand what you already did to modify the structure(s) before joining, or what you are trying to do now, sorry. > >> > >> You could send a session file if you want. > >> Elaine > >> ----- > >> Elaine C. Meng, Ph.D. > >> UCSF Chimera(X) team > >> Department of Pharmaceutical Chemistry > >> University of California, San Francisco > >> > >>> On Feb 8, 2021, at 12:35 PM, Moradkhan, Tiglath A <tmoradkhan(a)csus.edu> wrote: > >>> > >>> Hi > >>> > >>> I'm trying to join two models together using the Build Structure tool but I'm having problems. Here is my process. > >>> > >>> • Using the 3R2P crystal structure I select residues 3-130 from chain A and 131-182 from chain B > >>> • Then using the following command in Chimera I select the N atom of residue 130 that will form a bond with the C atom of residue 131: sel #0:130@N#1:131@C (#0 is the name of the 3-130 segment and #1 is the name of the 131-182 segment) > >>> • Then using the Build Structure tool I select Form C-N peptide bond, but the Apply button doesn't activate. > >>> I don't understand what the issue is. Is the command that I've written wrong? > >>> > >>> I would be very glad for your help. I can provide the pdb files of the residue segments if necessary. > >>> Thanks > >>> > >>> Tiglath > > > > > > _______________________________________________ > > Chimera-users mailing list: Chimera-users(a)cgl.ucsf.edu > > Manage subscription: https://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users > >

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Creating new models from existing crystal structures
by Moradkhan, Tiglath A 08 Feb '21

08 Feb '21

Hi I'm trying to join two models together using the Build Structure tool but I'm having problems. Here is my process. 1. Using the 3R2P crystal structure I select residues 3-130 from chain A and 131-182 from chain B 2. Then using the following command in Chimera I select the N atom of residue 130 that will form a bond with the C atom of residue 131: sel #0:130@N#1:131@C (#0 is the name of the 3-130 segment and #1 is the name of the 131-182 segment) 3. Then using the Build Structure tool I select Form C-N peptide bond, but the Apply button doesn't activate. I don't understand what the issue is. Is the command that I've written wrong? I would be very glad for your help. I can provide the pdb files of the residue segments if necessary. Thanks Tiglath

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Re: [Chimera-users] Video tutorials
by Tom Goddard 04 Feb '21

04 Feb '21

Hi Cynthia, Ok, I converted all the Chimera video tutorials (about 40 of them) to use standard web browser video playback. https://www.rbvi.ucsf.edu/chimera/videodoc/videodoc.html <https://www.rbvi.ucsf.edu/chimera/videodoc/videodoc.html> Thanks for pointing out that they were using the obsolete Flash plugin for movie playback. Tom > On Feb 4, 2021, at 10:29 AM, Cynthia Page wrote: > > Hi Tom, > Do you all have any plans of porting the tutorial flash videos to another player? I see there are some YouTube videos available for Chimera but I am thinking of the tutorials that are available on the website. > Maybe there is another source of video tutorial I am unaware of? > > Thanks very much, > Cynthia Page > CU Boulder > > Sent from my iPhone >

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MD simulation in Chimera : 10 ns simulation is equivalent to 1 million of production steps 10 fs each?
by Giovanni Roviello 29 Jan '21

29 Jan '21

Dear Sirs, I would like to perform a MD simulation by UCSF Chimera. Should I wish to perform a 10 ns simulation (for example) how could I set the parameters related to time? For example in production a number of phase steps of 1000000 and a time step of 10 fs is OK? Does the relaxation time Nosé thermostat has effect on the overall simulation time? In simpler words if I set 1000000 steps, 10 fs time step, and I leave selected Nosè thermostat with 0.2 ps (but leave unselected the barostat option) will it correspond to a 10 ns MD simulation? Of course if I will publish using Chimera I will cite the program and the reference as indicated in https://www.cgl.ucsf.edu/chimera/docs/credits.html Thank you in advance for your kind help. Kind regards, Giovanni _______________________________________________________ Dr. Giovanni N. Roviello, Ph.D. Researcher at Istituto di Biostrutture e Bioimmagini IBB - CNR; Via Mezzocannone 16; I-80134 Naples; Italy giroviel(a)unina.it giovanni.roviello(a)cnr.it http://www.ibb.cnr.it/?command=viewu&id=387&lang=en https://orcid.org/0000-0001-6065-2367

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less color depth possible?
by Cheng, Tat 27 Jan '21

27 Jan '21

Hi all, We are trying to set up cryoEM data processing in the university HPC. We use X2go for remote accessing the HPC, but it doesn't have enough color depth, so Chimera (24-bit) doesn't start. One workaround is to download the volume from HPC to local machine, but it is less convenient. But I wonder is there a way to use Chimera in less color? Thanks a lot. Best, Tat

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how to color an model by an attribute in chimerax
by sunyeping 27 Jan '21

27 Jan '21

Dear all, I wish to color an model by an attribute in chimerax. The attribute is the entropy which is calculted by an external software. I wrote the entropy values of each residue in a text file (attr.txt) like the following: attribute: entropy match mode: 1-to-1 recipient: residues :1 0.0 :2 0.0014948 :3 0.0090952 :4 0.0004805 :5 0.1102497 :6 0.0095258 :7 0.0008226 :8 0.0042205 :9 0.0037255 :10 0.0006678 :11 0.0027988 :12 0.0193925 :13 0.0153925 :14 0.0052115 :15 0.0020136 .......... However, when I input the command "color byattr attr.txt", I get the following error information: "No known/Registered attribute attr.txt" Could anyone tell me what is the correct way to do this? With many thanks. Best regards

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coloring the volume series
by Arto Pulk 26 Jan '21

26 Jan '21

Dear all, I would like to make a movie using volume series. I have 10 maps (from Relion) that I upload to volume series. Now I would like to color the moving parts of the map. One can use zone coloring, but it does not do the precise job to color specific volumes of the map as it is radius specific. Then there is "surface coloring" by "volume data value". I can make a mask and color the mask region, but it makes the color gradient and I do not have control of the region outside of the mask at it will be mixture of colors. The best way to color is to use "segment map" and then go to "Regions" and "color density map". It does good job to color specific map volumes but the colors are not permanent. If you Play the Volme Series then colors vanish. So, is there any good way to color Volume Series? Regards, Arto Institute of Technology University of Tartu Nooruse 1 50411, Tartu Estonia Dr. Arto Pulk email: arto.pulk(a)ut.ee phone: 58244846

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Chimera RMSD
by Elaine Meng 25 Jan '21

25 Jan '21

> From: "Sharyn Endow, Ph.D." <sharyn.endow(a)duke.edu> > Subject: Chimera RMSD > Date: January 23, 2021 at 11:27:17 AM PST > > Thank you for your work in developing Chimera. We are trying to use Chimera RMSD to quantitate twisting of a beta-sheet and would like to know what the syntax is to list rmsd values for specified residues corresponding to a beta-strand, not just for single residues. Is it possible to list these values using RMSD? If so, we would greatly appreciate knowing how to get started. > > Sincerely, > Sharyn Hi Sharyn, You can specify any sets of atoms/residues that you like in the RMSD command, as long as there are equal numbers of atoms in the two sets that you specify (from two different models). They will be paired in the order specified. We have a command-line "atom specification" syntax for that kind of thing. There is a longish page with lots of examples here: <https://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/frameatom_spec.html> In your case, you may need to specify residue numbers, chain ID, and possibly atom names if you just want to use alpha-carbons or backbone as opposed to all atoms of the residues. E.g. something like rmsd #0:12.A,57-63.A #1:14.A,59-65.A ... for all atoms of model 0 residues 12 and 57-63 in chain A vs. all atoms of model 1 residues 14 and 59-65 in chain A. Or to use CA-only or backbone only: rmsd #0:12.A,57-63.A@ca #1:14.A,59-65.A@ca rmsd #0:12.A,57-63.A@n,ca,c,o #1:14.A,59-65.A@n,ca,c,o Of course the numbers could be the same in the two models, I just was trying to give a more general example. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco P.S. the chimera-users(a)cgl.ucsf.edu address CC'd here is recommended for general Chimera how-to or is-it-possible types of questions

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