Re: [Chimera-users] All PDB ca atom pairwise distance

On Oct 31, 2017, at 9:54 AM, Kyle Morris wrote:

Dear chimera dev and users,

Is there a way to calculate (using the GUI, commands or using a python script) the pairwise distances for every single c-alpha atom in a set of loaded PDB coordinates and spit this out to a file for further analysis? There are 142,800 atoms in the current loaded assembly.

Do you mean CA-CA distances, or CA-any-other-atom distances? Even CA-CA only (assuming CAs are roughly 1/10 of your atoms) will be more than one hundred million distances, and CA-other will be more than a billion. Is this really what you want? If so, it would seem more efficient and much faster to write a special purpose program for this in a compiled language, like C, C++ or some such. It is of course doable in Chimera via Python. If you really do want to do it that way, I can offer further guidance... —Eric Eric Pettersen UCSF Computer Graphics Lab