[Chimera-users] [Chimera] Different bond width in the same model

Elaine Meng meng at cgl.ucsf.edu
Thu Oct 28 08:46:18 PDT 2021

On Oct 28, 2021, at 4:56 AM, Konstantin Richter <konstantin.richter at bbz.uni-leipzig.de> wrote:
> Dear Elaine,
> I am currently trying to create molecular figures with the old Chimera (not ChimeraX). I would like to represent different bonds in the same model in different bond widths: in my case, a disulfide bond should be represented thicker than the bonds of a nearby ligand.
> I already learned that the bond width is the product of the stick scale (which is a model attribute) multiplied by the bond radius (which is an atom attribute, if I got it right): https://www.cgl.ucsf.edu/pipermail/chimera-users/2013-November/009289.html
> So changing the bond radius for only the ligand atoms but not the disulfide atoms would do the job for me, right? Unfortunately I have no idea how to change the bond radius in the command line. Is there any command for that?
> Thanks in advance for your help!
> best wishes
> Konstantin Richter

Dear Konstantin,
You can change the bond radius in the Selection Inspector (e.g. select the part you want to change, then click the green magnifying glass in the lower right).  In the Selection Inspector, inspect: Bond, and then change the bond radius value for the current selection.  If you hold the mouse over the "radius" part of that dialog, a popup balloon says that the name of this bond attribute (for using in commands) is "radius"

If you prefer to use commands only, the command to set attribute values is "setattr," e.g.

setattr b radius 0.4 
 .... to change all bonds
setattr b radius 0.1 sel
... to change bonds in the current selection (and you can use any other atomspec, not just "sel", e.g. model numbers, residue names or numbers, etc.)

The general explanation of this and how to change it is

Selection Inspector

setattr command

I hope this helps,
Elaine C. Meng, Ph.D.                       
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco

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