- ChimeraX-users - RBVI Mailing Lists

Re: Chimera X Matchmaker RMSD
by Elaine Meng 25 Mar '24

25 Mar '24

(CC-ing chimerax-users(a)cgl.ucsf.edu since that is the recommended address for ChimeraX questions as long as they do not include private data. Email sent to me directly has more chance of falling through the cracks.) Dear Dr. Sharyn Endow, The Matchmaker algorithm in ChimeraX is the same as in Chimera. So everything I said before about Chimera's Matchmaker is also the case in ChimeraX. If you have the "iteration" option turned on it doesn't use all aligned columns but instead prunes residue pairs for a better fit of the core. If you are showing the sequence alignment, it shows what set of positions were used for the final fit as a light orange colored box. As before, it uses only the CA-CA pairs within those columns, not the side chains. These overall RMSD values are reported in the Log. "pruned" refers only to the fit iteration process, where iteration prunes away some pairs so that they are not used in the final fit. See "Fitting" at the bottom of the "Matchmaker" help: <https://rbvi.ucsf.edu/chimerax/docs/user/tools/matchmaker.html#fitting> Or, if you are using the "matchmaker" or "mmaker" command, see the "cutoffDistance" option for the description of iteration and pruning: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/matchmaker.html#options> If you mean the RMSD header across the top of the sequence alignment, that is a different thing calculated per column (not for the whole structures overall), and you can control in the Sequence Viewer Settings whether this RMSD histogram is calculated CA-only or backbone-only. Neither of them uses the sidechains. If a pairwise alignment, "CA RMSD" boils down to just the CA-CA distance. Simply selecting some range of residues on the sequence alignment doesn't change anything. See help for Sequence Viewer, its header lines, and its Settings: <https://rbvi.ucsf.edu/chimerax/docs/user/tools/sequenceviewer.html> <https://rbvi.ucsf.edu/chimerax/docs/user/tools/sequenceviewer.html#headers> <https://rbvi.ucsf.edu/chimerax/docs/user/tools/sequenceviewer.html#settings> Finally as mentioned in my previous answer about Chimera, you can use the "rmsd" command to calculate RMSDs over any sets of atoms that you choose (with or without sidechains) without changing the current positions of the structures. The more tricky part is that you have to specify in the command which atoms to pair with which atoms, since it is not calculated automatically like it is in Matchmaker. The syntax is a little different than in Chimera: there is a "to" between the two sets of atomspecs, and in ChimeraX the slash symbol "/" is used to indicate chains. "rmsd" command <https://rbvi.ucsf.edu/chimerax/docs/user/commands/rmsd.html> ChimeraX atomspec including many examples: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/atomspec.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco > On Mar 23, 2024, at 8:09 AM, Sharyn Endow, Ph.D. <sharyn.endow(a)duke.edu> wrote: > > Dear Dr Elaine Meng, > > We wrote to you a few years ago regarding Chimera RMSD and you were kind enough to send the information below. We now have a few Q's regarding Chimera X Matchmaker, which displays RMSD values, e.g., when all beta-strands are selected in the Sequence Viewer window. > > • We would like to know what the RMSD values correspond to after aligning two protein sequences using Matchmaker Iwhich uses only only one point per residue for fitting) and selecting all b-strands in the Sequence Viewer window. Is a single RMSD value calculated for each residue to obtain the average RMSD for the "pruned" or all atom pairs and, if so, is the RMSD value between the single point per residue that was used for fitting? > > • Is there some way to obtain the C-alpha RMSD values but not the side chain values, after aligning two protein chains in Matchmaker in Chimera X? > > • What does "pruned" atom pairs mean in this context? > > T > hank you in advance for your help - > > Sincerely, > > Sharyn A. Endow, PhD > Professor of Cell Biology, DUMC > DUS, Cell Biology > PO Box 3709 / 245/247 Sands Bldg / 303 Research Drive > Durham, NC 27710 USA T 919 684-4311 F 919 681-9929 > > > > From: Elaine Meng <meng(a)cgl.ucsf.edu> > Date: January 25, 2021 at 4:26:34 PM EST > To: "Sharyn Endow, Ph.D." <sharyn.endow(a)duke.edu> > Cc: Chimera <chimera-users(a)cgl.ucsf.edu> > Subject: Chimera RMSD > Reply-To: Chimera <chimera-users(a)cgl.ucsf.edu> > > > 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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isolde write phenixRsrInput (how to restrain ions?)
by Shahid, Taha (Dr.) 25 Mar '24

25 Mar '24

Dear Tristan, I find ISOLDE invaluable for my work. Not only has it enabled me to build models of the highest quality, but been hugely instructive in giving me an instinctive ‘feel' for protein structure. I am having a minor problem with magnesium ions moving out of density when I run phenix.real_space_refine with settings output by isolde write phenixRsrInput. I typically specify restrainPositions true and includeHydrogens true as well. Is there a way to restrain these ions as well (perhaps an edit I could make to the real_space_refine.eff file)? Many thanks, Taha

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ISOLDE query - non crystallographic symmetry?
by Oliver Clarke 25 Mar '24

25 Mar '24

Hi Tristan, I've been using the latest version of ISOLDE with ChimeraX 1.7.1 and it is working beautifully - very smooth simulation and very helpful for fixing up problem areas! One query - is there any support for non crystallographic symmetry in ISOLDE, or if not is this on the roadmap? Thinking both in terms of NCS restraints, but also in terms of propagating edits from one subunit of an oligomer to all the others - this would be very helpful to have for a lot of folks I think, as so many proteins are oligomeric. Thanks for the wonderful piece of software! Cheers Oli

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Difficulty unsubscribing
by BARRY E DEZONIA 24 Mar '24

24 Mar '24

I am trying to leave this email list and currently am unable to. I send email to: chimerax-users-leave(a)cgl.ucsf.edu And it processes and says my email barry.dezonia(a)wisc.edu is not a list member. That is because I signed up with bdezonia(a)wisc.edu.. My mail service treats them as equivalent but it only sends out on the incorrect email address. Can someone unsubscribe ndezonia(a)wisc.edu? I can't figure out how to get my email client to use my other email address as the sending address.

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Adding lipid bilayers to chimerax movie
by Kevin Felt 24 Mar '24

24 Mar '24

Hello ChimeraX Users, I'm trying to make a movie in chimerax involving a membrane protein, and I would like to have some representation of where the inner and outer lipid bilayer leaflets are relative to the protein transmembrane region, ideally represented as phospholipids. Is it possible to do this within Chimerax? I've thought about encoding the movie to mp4 and then figuring out how to simply overlay a bilayer image onto the mp4 where I want with some other software , but I foresee resolution and scaling issues when doing that. Thank you! Sincerely, -- Kevin C. Felt PhD Candidate - Chakrapani Lab Department of Physiology and Biophysics School of Medicine Case Western Reserve University

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Color a surface by seq_conservation of neighboring residues
by Esser, Lothar (NIH/NCI) [E] 22 Mar '24

22 Mar '24

Hi, my intention is to make a figure that maps the degree of sequence conservation of surrounding residues onto a surface drawn over the said inhibitor. I know I can color surfaces by distances and other parameters but I could not find out how to color a surface by properties of neighboring residues or atoms. Is there perhaps a way to convert an atom attribute like conservation into a map that then could be used to color a surface? Alternatively, I thought I could write out the calculated sequence conservation as a pdb file with say the b-factor column representing the sequence conservation. Unfortunately, that does not seem to be the case. Can you write atom attributes in any other way? - perhaps I missed that. If I had access to the sequence conservation values, I could copy them to the b-factor column of the inhibitor and color its surface by bfactor. Thanks for any advice. Lothar NIH

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Visualisation of distances
by Enrico Martinez 21 Mar '24

21 Mar '24

Dear ChimeraX users ! I need to draw several distance vectors on the 3D structure. Could you provide me with an example of the commands that could automatically draw the distances between two selected atoms with some basic labels on it ? Many thanks in advance Enrico

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Re: Trying to join two structures unsuccessfully
by Maja Divjak 17 Mar '24

17 Mar '24

Alternatively, I guess I could just cut this disordered domain into fragments, move them around and the rejoin them.... -----Original Message----- From: Maja Divjak Sent: Tuesday, 5 March 2024 11:44 AM To: ChimeraX Users Help <chimerax-users(a)cgl.ucsf.edu> Subject: RE: [chimerax-users] Trying to join two structures unsuccessfully Dear Elaine, No worries at all, I have received multiple replies, so it is working! Thank you for your response below. Basically, it seems what I'd like to do can't really be done in this way. In another conversation, someone mentioned the tug command. Could this yield what I'm hoping for please? The two ends I'm trying to join are indeed in separate models, so I tried the following command: tug #16/a:345-355 toAtoms #18/A:345-355 which gave the following error: For 0 tugged atoms expected 0 destination atoms, got 84 Would this be the correct approach (I've clearly got the syntax wrong) or is there really no way to do this in Chimera X? Thanks so much and best wishes, Maja PS. How do I join the member's list please? -----Original Message----- From: Elaine Meng <meng(a)cgl.ucsf.edu> Sent: Tuesday, 5 March 2024 11:33 AM To: Maja Divjak <Maja.Divjak(a)petermac.org> Cc: ChimeraX Users Help <chimerax-users(a)cgl.ucsf.edu> Subject: Re: [chimerax-users] Trying to join two structures unsuccessfully ! EXTERNAL EMAIL: Think before you click. If suspicious send to CyberReport(a)petermac.org Dear Maja, Apologies if you are getting multiple copies of this answer from me. I keep getting error messages that my reply could not be sent to the list! So, here is my third try. If you've been getting my previous messages (even though I don't think the rest of the list is), please ignore and pardon me for the spam! Adding a bond only works when the atoms are in the same model as each other (typically a structure opened from one PDB file is one model). Also simply adding a bond won't move anything. It will just make a long bond between the atoms in their current positions, or if you choose "reasonable" only, it won't add any bond because the bond would be too long to be reasonable. <https://rbvi.ucsf.edu/chimerax/docs/user/tools/buildstructure.html#bonds> You can see what model(s) you have by looking in the Model Panel: <https://rbvi.ucsf.edu/chimerax/docs/user/tools/modelpanel.html> If the two atoms are in two different models (typically opened from two different input files), the "join models" Peptide Bond option should work if you really have exactly two atoms selected, the peptide terminal "N" in one model and the peptide terminal "C" in the other model. As far as I can tell these two are selected in your image, so I couldn't say why you get an error message. If the atoms are in the same model as each other, however, it will not work. You would need to split the model so that they are in separate models first. You can try command "info atoms sel" to list in the Log what you have selected. In my "join peptide" test case I get the following, which confirms I have the correct atoms from two different models selected: info atoms sel atom id #1/A:29@C idatm_type Cac atom id #2/A:1@N idatm_type N3+ However, join models is not going to change the conformation of the peptide, it will just move one model (e.g. the entire green one if it has more atoms than the purple one) as a rigid body to form the specified bond with the other model. <https://rbvi.ucsf.edu/chimerax/docs/user/tools/buildstructure.html#join> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco

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How to change transparency of ladder mode of nucleic acids
by Yan ZHANG 张艳 15 Mar '24

15 Mar '24

Dear ChimeraX Team, I hope this email finds you well. My name is Zhang Yan, and I am a beginner of ChimeraX. I am writing to seek assistance regarding how to change transparency of ladder mode of nucleic acids in ChimeraX. Despite trying the command 'trans #1 60 all', I have been unable to achieve the desired effect. Could you please suggest an alternative solution or provide guidance on how to accomplish this task? Thank you for your attention to this matter. Best regards, Zhang Yan

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Is the site down ?
by Marie PREVOST 14 Mar '24

14 Mar '24

Hello, I would like to install ChimeraX on my new laptop but the site seems to be down… Do you know if there are other option to download the installer ? Thank you for your help Best wishes ------- Marie Prevost, PhD Pierre-Jean Corringer’s lab ( site<https://research.pasteur.fr/en/member/marie-prevost/> ) Channel-Receptors Unit Institut Pasteur 25 rue du Dr Roux 75015 PARIS France +33 (0)1 53 55 15 06 (via Teams)

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