Hi Emily, As I understand it, the chain ID has to be constant within a covalently bonded biopolymer chain. If there were also waters, ligands, etc. with the same chain ID they could be changed to different IDs, but all the residues in the bonded chain (peptide or nucleic) must retain the same chain ID as each other. In general if you try to change part of a biopolymer chain, e.g. open 6bna changechains /A:5-10 D ... there will be an error message in the Log explaining this: Cannot reassign chain ID to only part of polymeric chain (/A) I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco
On Oct 29, 2025, at 2:12 PM, Emily Cioppa via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:
Good evening, I have a quick question regarding the changechains command in Chimera/ChimeraX. If I have a single model open that inherently has one single chain, is there a way to select a continuous strand of residues in the sequence and change the Chain ID of only the selected residues to something else? It seemed from my online research that this is possible, however, I cannot get it to work. Any advice would be appreciated as soon as possible. Thank you. Best, Emily Cioppa Research Assistant The Rockefeller University