August 2023 - ChimeraX-users - RBVI Mailing Lists

Regarding Volume Morph Issue
by Chen, Shin-Fu 11 Aug '23

11 Aug '23

Hello, I hope this message finds you well. I am currently working on creating a movie using the "volume morph" command based on ten sets of mrc files. I have encountered an issue that I would appreciate your assistance with. Prior to applying the "volume morph" command, I have utilized the "color near atoms" option to assign colors to the visualization. However, after executing the "volume morph" command, the previously assigned colors are reset to a default single color. I am reaching out to seek guidance on resolving this issue. Your insights and advice would be greatly appreciated. Thank you for your attention to this matter, and I eagerly await your response. Best regards, Shin-Fu Shin-Fu Chen, Ph.D. Postdoctoral Fellow Department of Biochemistry and Molecular Biology McGovern Medical School University of Texas Health Science Center Houston 6431 Fannin St | MSB 6.326 | Houston, Texas 77030

2 2

Re: [Chimera-users] making composite map using vop maximum command
by Elaine Meng 10 Aug '23

10 Aug '23

Hi, In ChimeraX it is documented as "volume maximum" (even though I believe that "vop maximum" like in the older program Chimera could be used). Also if you want to ask about ChimeraX specifically, there is a different email address, chimerax-users(a)cgl.ucsf.edu -- I CC'd it here so you don't need to do anything this time. Here is the ChimeraX "volume maximum" help link: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/volume.html#maximum> For example, if your maps are #2 and #3, you can create a new map containing the maxima of their two values with ChimeraX command: vol max #2,3 ... but there are many additional options that could also be included in that command, so you should check the help link above to see if you want to use any of them. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco > On Aug 7, 2023, at 2:20 PM, ytakagi--- via Chimera-users <chimera-users(a)cgl.ucsf.edu> wrote: > > Hi > I want to make a composite map using two locally refined maps. I tried Phenix but did not work well. So, I like to do it by Chimera. Apparently, a composite map can be made using Chimera's vop maximum command. But I could not find the instruction of how to do it. Can you tell me how to do it? > Thanks

2 5

Spherical mask
by Grundmann,Lorenz Emanuel 10 Aug '23

10 Aug '23

Dear chimerax-team, I am looking into a possibility to generate a spherical volume in chimerax that I can then use as a spherical mask for focused 3D classifications and signal subtractions. For my specific need, a sphere would be the ideal shape. So far I managed to generate a surface model using the ‘shape sphere’ command, to place it to the region of interest and resampling it onto the coordinate system of my protein of interest. Is there any possibility to transform the surface model into a (binarized) volume? Best, Lorenz

3 4

Re: Advice on handling cofactor-protein electrostatic interactions
by Boaz Shaanan 08 Aug '23

08 Aug '23

Thanks Elaine, I'll do just that. Cheers, Boaz Boaz Shaanan, Ph.D. Dept. of Life Sciences Ben-Gurion University of the Negev Beer-Sheva 84105 Israel E-mail: bshaanan(a)bgu.ac.il Phone: 972-8-647-2220 Fax: 972-8-647-2992 or 972-8-646-1710 ________________________________ From: Elaine Meng <meng(a)cgl.ucsf.edu> Sent: Tuesday, August 8, 2023 11:57 AM To: �� <bshaanan(a)bgu.ac.il> Cc: ChimeraX Users Help <chimerax-users(a)cgl.ucsf.edu> Subject: Re: [chimerax-users] Advice on handling cofactor-protein electrostatic interactions Hi Boaz, If you use Coulombic it will automatically calculate the charges, as in my example of 1qs0 with the TPP residue. I.e. you don't have to do it in a separate step first, and in fact it may be better if you do not: if you use Add Charge first, it will also add hydrogens and make the surface a lot bumpier. If you just use Coulombic the hydrogens are added only on a temporary copy that is in memory, not on your model, and the coloring will be applied to the smoother molecular surface without hydrogens. You just need to substitute the cofactor residue name for ":tpp" in my example, if it is not TPP. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco > On Aug 8, 2023, at 7:09 AM, Boaz Shaanan via ChimeraX-users <chimerax-users(a)cgl.ucsf.edu> wrote: > > Hi Elaine, > > Thanks a lot for the detailed reply and (as always) very helpful suggestions. I'll experiment first with the Chimerax coulombic surfaces and trick to include the cofactor. This sounds attractive, certainly for the TDP case as a starting point. As for derivatives of TDP, which are already included in the pdb, I guess I should follow the 'Add Charges' guide, right? > > Thanks again. > > Boaz > > > Boaz Shaanan, Ph.D. > Dept. of Life Sciences > Ben-Gurion University of the Negev > Beer-Sheva 84105 > Israel > > E-mail: bshaanan(a)bgu.ac.il > Phone: 972-8-647-2220 > Fax: 972-8-647-2992 or 972-8-646-1710 > > > > > From: Elaine Meng <meng(a)cgl.ucsf.edu> > Sent: Monday, August 7, 2023 10:17 PM > To: �� <bshaanan(a)bgu.ac.il> > Cc: chimerax-users(a)cgl.ucsf.edu <chimerax-users(a)cgl.ucsf.edu> > Subject: Re: [chimerax-users] Advice on handling cofactor-protein electrostatic interactions > > Hi Boaz, > This answer addresses coloring by electrostatic potential (ESP). Calculating the electrostatic interaction per se (energy?) is somewhat different and not something that ChimeraX does. > > ChimeraX can color some surface, which could be a molecular surface, by the values in a 3D map, which could be electrostatic potential (ESP). See "color electrostatic" > <https://imsva91-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%…> > > The ESP map can come from a Poisson-Boltzmann calculation (APBS, DelPhi, others) or from a more simplistic Coulombic calculation which can be done directly in ChimeraX. > > Poisson-Boltzmann calculations require atomic coordinates, partial charges, and radii, but the different programs differ in how you input these values. > > If I recall correctly, APBS takes as input a pqr file (q means charge, r means radii) which would usually be generated by PDB2PQR, but you said PDB2PQR throws out the nonstandard residues like cofactors, I guess because it doesn't have charges for them. ChimeraX assigns radii and can assign atomic partial charges (via lookup table for standard residues and Antechamber calculation for nonstandard residues like cofactors). However, ChimeraX does not write pqr format. Also in ChimeraX, these partial atomic charges are for all atoms (i.e. all hydrogens explicit) and not a united-atom model (in which hydrogens on carbons are merged with those carbons so that they become implicit) which is often used for Poisson-Boltzmann calculations. So if you wanted to go the APBS route, in ChimeraX you would add hydrogens and charges, then save the cofactor radii and atomic partial charges (atom attributes "radius" and "charge") in the attribute file format, and if you were using a united-atom charge model, manually generate united atoms from CH, CH2, and CH3 groups in the cofactor by adding the hydrogen charges to those of the carbons where they are attached and figuring out the appropriate united-atom radii, then reformat the cofactor atom coordinates, radii and charge values into pqr format and then add these lines to your protein pqr file from PDB2PQR, then use the resulting combined pqr file as input to APBS to get the ESP map that includes cofactor contributions. > > Actually I don't even know if APBS would accept that pqr file or not, but that is what I imagine you would try. So let's assume the APBS calculation will run using that pqr file. > > Then you would open the APBS ESP map that includes cofactor contributions in ChimeraX and color the molecular surface. If the cofactor is covalently attached to the protein then the protein molecular surface may already include it. However, if the cofactor is not covalently attached, you would need to tell ChimeraX specifically to lump it inside of the same surface as the protein with the "include" option of "surface" when you are calculating and displaying the molecular surface. > > The "coulombic" approach wil do more of these steps for you, given the "include" trick as well as the "surfaces" option of the "coulombic" command, but calculating ESP with the relatively simplistic Coulomb's law method. For example, 1qs0 chain A includes a noncovalently bound TPP residue and I could show the surface including the TPP and colored including its potential contribution: > > open 1qs0 > surf include :tpp > coulombic surfaces #1.2 > > <https://imsva91-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%…> > <https://imsva91-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%…> > > See first image attached with :tpp selected (green outline surface patch) > > If you don't use the "include" and "surfaces" options in these commands, the surface will be redrawn to include only the protein part with the TPP outside of it, like other ligands and the Coulombic ESP will not include the TPP contribution. See second image attached. > > I hope this helps, > Elaine > ----- > Elaine C. Meng, Ph.D. > UCSF Chimera(X) team > Department of Pharmaceutical Chemistry > University of California, San Francisco > > <Screen Shot 2023-08-07 at 7.08.37 PM.png><Screen Shot 2023-08-07 at 7.12.43 PM.png> > > >> On Aug 7, 2023, at 4:10 PM, Boaz Shaanan via ChimeraX-users <chimerax-users(a)cgl.ucsf.edu> wrote: >> >> Hi, >> >> I would like to present effects of mutations around cofactors (TDP derivatives) on the protein - cofactors electrostatic interactions. I use APBS and chimerax to display the electrostatic surface potential of the protein, but since PDB2PQR eliminates the cofactor from the pqr file I need a tool for the cofactor surface potential. I'm wondering what tool I should use for this. Is it Antechamber+chimerax or something else? >> Is there by chance a demo for such scenario? >> I'd appreciate your advice. >> Cheers, >> >> Boaz >> >> >> Boaz Shaanan, Ph.D. >> Dept. of Life Sciences >> Ben-Gurion University of the Negev >> Beer-Sheva 84105 >> Israel >> >> E-mail: bshaanan(a)bgu.ac.il >> Phone: 972-8-647-2220 >> Fax: 972-8-647-2992 or 972-8-646-1710 >> >> >> >> >> _______________________________________________ >> ChimeraX-users mailing list -- chimerax-users(a)cgl.ucsf.edu >> To unsubscribe send an email to chimerax-users-leave(a)cgl.ucsf.edu >> Archives: https://imsva91-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%… > > _______________________________________________ > ChimeraX-users mailing list -- chimerax-users(a)cgl.ucsf.edu > To unsubscribe send an email to chimerax-users-leave(a)cgl.ucsf.edu > Archives: https://imsva91-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%…

1 0

Re: [Chimera-users] Saving phi psi values to a text file
by Elaine Meng 07 Aug '23

07 Aug '23

Hi Prathvi, In Chimera there is no command to save attributes. Instead you have to use the Render by Attribute dialog's File menu as described in the bottom section of this page: <https://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/render/render.ht…> In ChimeraX, as far as I know you can only save one attribute to a file at a time with the "save" command. However, it would probably work just to use the "save" command several times and then (outside of ChimeraX) concatenate the multiple files into one file afterward. <https://rbvi.ucsf.edu/chimerax/docs/user/commands/save.html#attributes> Another idea is that in ChimeraX you can list attribute values in the Log with the "info" command, e.g. info residues protein attribute phi So an alternative approach if you don't need the file to be in the attribute-file format is to use "info" multiple times and then save the Log contents to an HTML file with "log save" -- see help pages for those commands: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/info.html#residues> <https://rbvi.ucsf.edu/chimerax/docs/user/commands/log.html#save> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco > On Aug 5, 2023, at 10:14 AM, Prathvi Singh via Chimera-users <chimera-users(a)cgl.ucsf.edu> wrote: > > Hi Elaine, > > Is there a command to save the phi and psi angle values of each residue of a PDB file in a text file using UCSF chimera? > > I know we can do this in chimeraX using the command: save C:\myphi.defattr attrName phi format defattr model #1 > > Also, can we use chimeraX to save the phi and psi values in a single file? > > Thanks in advance >

2 1

Query regarding selection
by Prathvi Singh 04 Aug '23

04 Aug '23

Hi Elaine, I want to select all the atoms except the backbone oxygen and nitrogen atom of residues 100.A to 120.A . Is there a command to do this in either chimera or chimeraX? -- Prathvi Singh, Research Fellow, Department of Biological Sciences & Bioengineering, Indian Institute of Technology, Kanpur-208016

2 2

Pseudobonds question
by Aleksei Solomonov 02 Aug '23

02 Aug '23

Dear ChimeraX Developers, I apologize for disturbing you, I have a question, how can I make pseudobonds in ChimeraX similar to Chimera? I mean when I try to create hydrogen bonds, by default, in Chimera (Tools->structure analysis->findHbonds) they appear as lines (or sticks), connected to the structure (left image). But if I export the model and import it in ChimeraX bonds become "disconnected". The same appeared if I place H-bonds directly in ChimeraX (right image). If I select pesudobond, an option of changing its length manually is unavailable. The structure is attached if needed. [cid:image002.png@01D9C590.A8D2F3A0] Thank you in advance! Best regards, Aleksei

2 2