November 2022 - ChimeraX-users - RBVI Mailing Lists

Distance between two atoms
by McClean, Phillip 17 Nov '22

17 Nov '22

Hi Everyone, I have a two chain model. I would like to determine the distance between the CD1 atom of residue 77 in chain B and the CD1 atom of residue Leu 150 in chain C. What would be the proper distance command. Thanks for the help again. Phil McClean

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Re: [chimerax-users] [Chimera-users] Finding SASA for individual residues
by Elaine Meng 17 Nov '22

17 Nov '22

On Nov 17, 2022, at 8:01 AM, Prathvi Singh via Chimera-users <chimera-users(a)cgl.ucsf.edu> wrote: > > Hi Elaine, > > The methods you suggested for calculating SASA for residues saved me so much time. Thank you once again for it. > But I have noticed an ambiguity. > When I calculate the SASA for the same residue using chimera and chimeraX, I am getting different values. > For ex: in the PDB file 1TY4, the SASA value for residue 174.a is 2.55 when calculated using chimera and it is 292.44 when calculated using chimeraX. The same is true for other amino acids in other PDB files as well. > Why is there such a difference? > On which of the two software should I rely on? > Also, what is the unit of SASA calculated by these two softwares? > > On Mon, Nov 14, 2022 at 9:42 PM Elaine Meng <meng(a)cgl.ucsf.edu> wrote: > [...] > In Chimera, they are automatically calculated when you show a molecular surface. It creates an attribute named areaSAS, as explained here: > <https://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/representation.html#surfa…> > > See also this previous chimera-user post on using Chimera to get a list of residue SASA values > <http://www.cgl.ucsf.edu/pipermail/chimera-users/2018-June/014729.html> > > (If you use this page <https://www.rbvi.ucsf.edu/chimera/docs/feedback.html> to search chimera-users by "sasa", that was the top hit) > > In ChimeraX, you would use the command "measure sasa" > <https://rbvi.ucsf.edu/chimerax/docs/user/commands/measure.html#sasa> > ... then save attribute "area" to file > <https://rbvi.ucsf.edu/chimerax/docs/user/commands/save.html#attributes> > Hi Prathvi, The atomic coordinates are in angstroms so the surface areas are in angstroms squared. Since this answer is mostly about ChimeraX, I'm also CCing the chimerax-users list. Regarding the differences in value: The programs are both right but based on different surfaces. By default, Chimera encloses all of the protein chains together into one surface (and chain A residue 174 is buried by some interactions with chain C, which you can probably see if you look at the structure). In ChimeraX, the default for display is to make each chain a separate surface, but for SASA calculation, it only depends on what you wrote in the "measure sasa" command. <https://rbvi.ucsf.edu/chimerax/docs/user/commands/measure.html#sasa> As mentioned in my earlier answer, the important part of what you get from "measure sasa" is not (in your case) the total reported in the Log, but instead the "area" attribute value that you will get for each residue. If you just use this ChimeraX command: measure sasa /A:174 ... then it will make a surface that only encloses that one residue, with area 292 as you said. I'm pretty sure that is NOT what you want. Instead you want tthe surface of the whole protein (or maybe one chain) and then the area of the residue given that larger surface. If you wanted to enclose all the protein chains of a model in a single surface (like Chimera default), then measure sasa protein If you wanted to make a separate surface for chain A only, then something like measure sasa /A & protein (the & protein part is still needed so that it won't enclose ligands, water, etc. that also happen to have chain ID A) Using "measure sasa" gives the residue "area" attribute that you could save to file, show in labels, etc. as explained in the help: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/save.html#attributes> <https://rbvi.ucsf.edu/chimerax/docs/user/attributes.html> For your example structure 1TY4, using these ChimeraX commands: measure sasa protein info residues attribute area ...gives 2.55 for residue 174 in chain A, the same as in Chimera. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

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Multiplying the model around the helical cryo-EM map
by Dmitry Semchonok 16 Nov '22

16 Nov '22

Dear colleagues, I am trying to multiply the model subunit into the helical density. I found some command for Chimera sym #1 group c2*h,4.328,23.27,120,1 center 191.99,191.99,191.99 coord #0. Probably I have to somehow find the centre - perhaps with this command, right? Measure center #1 But not for ChimeraX. So my question is, how to do that in ChimeraX? Could you please provide the usage - it would be most helpful. Thanks in advance! Kind regards, Dmitry

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Bond Rotation Questions
by FUNG Chun Po 15 Nov '22

15 Nov '22

Hello I have recently tried to use the bond rotation feature of Chimera X (Windows 10), and I have not been able to get it to work. I have tried the Bond rotation button on the toolbar, and the torsion command to no avail. The bond rotation button does not seem to do anything even when I click and drag with right click. The Torsion command states that my bond “is part of a ring/cycle and cannot be rotated” or “To set torsion, middle two atoms (/A ARG 543 N C) must be bonded;they aren't” I want to ask how do I use this function to rotate upon a simple amide bond. I am not sure am I just selecting the wrong atoms/bonds or is the function just locked for this PDB. The PDB file I am using is 7Y4P and I am trying to rotate about residues 543-544. I have also tried to do it in normal Chimera’s rotation command with no results. Thank you any advice would be welcome. Regards, Chun Po Fung

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create chain as a new model from exiting PDB model
by tim smith 15 Nov '22

15 Nov '22

Hi All, I would like to create chain A as a separate model from the existing model. Could you please help me. Thank you. Best regards Tim

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Question about pad parameter
by Thu Nguyen 14 Nov '22

14 Nov '22

Hello, I am using the volume cover command to crop the chain from the protein map. Here is what I did: > open 12554 from emdb > open 7ns0 > volume cover #1 atomBox #2/A1 pad 1.0 Suppose I want to add extra 17 voxels on each size of the chain, what value of pad should I add? Also, could you tell me the unit of pad in this command? Thank you very much. Best regards, Thu

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Re: [chimerax-users] Google colab sign in inquiry
by Tom Goddard 14 Nov '22

14 Nov '22

Hi Alejandro, On Windows the QtWebEngine Google Colab authentication info is in C:\Users\<username>\AppData\Roaming\ChimeraX\QtWebEngine\AlphaFold You can delete that directory and try using ChimeraX AlphaFold prediction again. Tom > On Nov 14, 2022, at 5:38 PM, Abraham, Alejandro <alejandro.abraham(a)icahn.mssm.edu> wrote: > > Hi Tom, > > Thank you for your email. I cannot see the login page anymore, and uninstalling ChimeraX to later reinstall it does not work. > Is there a folder where sign in is saved like in Macs ? I am using a Windows 10 PC. > Thanks again. > > Best, > > Alejandro > > > On Mon, Nov 14, 2022 at 12:59 PM Tom Goddard <goddard(a)sonic.net <mailto:goddard@sonic.net>> wrote: > Hi Alejandro, > > ChimeraX remembers your Google Colab sign-in. I don't understand why it would not let you sign in. A screenshot showing what you see would help understand the problem. > > If you signed in and ran AlphaFold previously but you want to change the account you sign in with, that should also be possible by clicking the image in the upper right corner of the AlphaFold Run panel which is just a web browser -- that button which shows the icon for your Google account will pull down a menu and let you sign out. And then you can also use it to sign in to another account. > > If somehow the ChimeraX remembered Google sign-in is causing problems you can delete that remembered sign-in info. On Mac you would delete the directory > > ~/Library/Caches?/UCSF ChimeraX/QtWebEngine/AlphaFold > > This is described further in this ChimeraX bug report > > https://www.rbvi.ucsf.edu/trac/ChimeraX/ticket/7654#comment:2 <https://www.rbvi.ucsf.edu/trac/ChimeraX/ticket/7654#comment:2> > > Tom > > >> On Nov 14, 2022, at 7:36 AM, Abraham, Alejandro via ChimeraX-users <chimerax-users(a)cgl.ucsf.edu <mailto:chimerax-users@cgl.ucsf.edu>> wrote: >> >> Dear ChimeraX Support Team, >> >> Before all, congratulations on such awesome software. >> On another note I wanted to contact you because I am not able to connect to Google sign in when trying to predict with alpha fold. Is there a way to reset login ? >> >> Thanks again. >> >> Best, >> >> Alejandro >> >> _______________________________________________ >> ChimeraX-users mailing list >> ChimeraX-users(a)cgl.ucsf.edu <mailto:ChimeraX-users@cgl.ucsf.edu> >> Manage subscription: >> https://www.rbvi.ucsf.edu/mailman/listinfo/chimerax-users <https://www.rbvi.ucsf.edu/mailman/listinfo/chimerax-users> >

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stretching protein?
by Noriega, Heather 14 Nov '22

14 Nov '22

Hello, I hope this email finds everyone well. I was wondering if ChimeraX had a function specific to "stretching" the protein. I am going to attach a picture, for reference. Is it possible to stretch the monomer to build a larger capsid? Thanks in advance. Thank you, Heather Noriega PhD-Pharmaceutical Science student Howard University heather.noriega(a)bison.howard.edu 520-203-1883 [image: image.png]

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Export PAE plot
by Clara Jegousse (TSL) 14 Nov '22

14 Nov '22

Dear ChimeraX team, After watching the YouTube tutorial on “how to show AlphaFold error estimates with ChimeraX”, I was wondering how to export the plot as an image (pdf, png?). Kind regards, Clara

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Google colab sign in inquiry
by Abraham, Alejandro 14 Nov '22

14 Nov '22

Dear ChimeraX Support Team, Before all, congratulations on such awesome software. On another note I wanted to contact you because I am not able to connect to Google sign in when trying to predict with alpha fold. Is there a way to reset login ? Thanks again. Best, Alejandro

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