March 2023 - ChimeraX-users - RBVI Mailing Lists

Build Structure - peptide
by Jeffrey D. Hartgerink 07 Mar '23

07 Mar '23

Hello, I’m trying to build a series of related peptides with ChimeraX’s Build Structure - peptide tool. The way it currently works is simple and easy to use. However it is cumbersome to input phi/psi angles repeatedly, especially if the peptide sequences is anything more than very short. I am wondering if there is a way for this tool to take in either a text file list containing (Amino Acid, Phi, Psi), to paste in the same data into the input window, or any other related way to more efficiently generate peptide structures for starting points. This would greatly reduce the time needed to compare a variety of related sequences and conformations. Thank you very much for your time and consideration! -Jeff ---------------------------------------------- Jeffrey D. Hartgerink, Ph.D. Prof. of Chemistry and Bioengineering Rice University jdh(a)rice.edu / 713-348-4142 https://hartgerink.rice.edu

2 2

Fwd: Request for Help with Chimerax and Protein Visualization
by Eric Pettersen 02 Mar '23

02 Mar '23

> Begin forwarded message: > > From: Ratchanont Viriyakitkosol <ratchanont.vir(a)gmail.com> > Subject: Request for Help with Chimerax and Protein Visualization > Date: March 2, 2023 at 12:26:42 AM PST > To: pett(a)cgl.ucsf.edu > > Dear Eric Pettersen, > > I hope this email finds you well. I am a medical school undergraduate student, and I have been using Chimerax to visualize protein structures that I predicted using AlphaFold. I am reaching out to you as I have encountered some difficulties with visualizing chemical bonding interactions in Chimerax, and I was hoping you could provide some guidance. > > Firstly, I have been using the "contacts" command in Chimerax to visualize chemical bonding interactions that interact with a single amino acid. However, I am not sure if this is the correct command to use. The visualization only shows blue dashlines, which I assume are hydrogen bonds. However, I am not sure if it is showing all direct interactions, including polar and nonpolar, favorable and unfavorable (including clashes). I want to know what is meant by "favorable and unfavorable" interactions in this context. > > Secondly, I have been unable to find a command to show disulfide bonds within a protein in Chimerax. I know that Pymol can show disulfide bonds in the same model, but I find Chimerax easier to use. Could you please let me know how to visualize disulfide bonds in Chimerax? > > As an undergraduate student with limited knowledge of structural analysis, I want to ensure that the bonding I use in my manuscript is shown correctly. I would greatly appreciate any advice or guidance you could provide. > > Thank you for taking the time to read my email, and I look forward to your reply. > > > > Best regards, > > James >

2 2

Inquiry about bond type generated by the "contacts" command with default settings for AlphaFold-generated protein structure
by stomp.pumped0g＠icloud.com 02 Mar '23

02 Mar '23

Dear UCSF ChimeraX team, I hope this email finds you well. I am writing to inquire about the bond type generated by the "contacts" command with all default settings in UCSF ChimeraX for a protein structure that was generated using AlphaFold. I am particularly interested in understanding the nature of the blue line that is generated after running this command. As a reminder, my protein structure was generated using AlphaFold, and I would like to know if the bond type is a hydrogen bond, salt bridge, disulfide bond, or another type of bonding. Any information or insight you could provide on this matter would be greatly appreciated. Thank you for your time and assistance. Best regards, James

2 1

Discrepancies in SASA values between chimera and chimeraX
by Prathvi Singh 02 Mar '23

02 Mar '23

Hi Elaine, I compared the SASA values generated by chimera and chimeraX for a few PDB files and I noticed that whenever the SASA value of a residue is reported to be zero by chimera, the same residue's SASA value is reported to be -1.42 by chimeraX. Few examples are 18.A and 38.A of the PDB ID 1A62. *Method used to calculate SASA of residues in chimera: *Tools > Structure analysis > Render by attribute *Method used to calculate SASA **of residues** in chimeraX: *I ran the following commands: measure sasa protein;info residues attribute area Why is this happening? Kindly help. -- Prathvi Singh, Research Fellow, Department of Biological Sciences & Bioengineering, Indian Institute of Technology, Kanpur-208016

2 2

Ring fill color
by Luca Pellegrini 01 Mar '23

01 Mar '23

Is it possible to color differently the ring fill for sugar and base in DNA? When I select just the bases or just the riboses and then apply color using the ‘ring fill’ option, they both change to the new color. Thanks, Luca Luca Pellegrini, PhD Department of Biochemistry University of Cambridge Cambridge CB2 1GA UK

2 1

Update pdb model in cxs session
by 张一小 01 Mar '23

01 Mar '23

Hi, I'm using ChimeraX to prepare figures. I saved a session containing several pdb files and maps. (The pdb files were saved in the CXS file right?) Now, I manually adjusted one of the models in Coot. Is there a way to update the old model with the new one in the session so that all the settings, such as colors, views, showing residues, hidden ribbons can be kept and applied?" Thanks, Yixiao

2 3