If you are reading in a PDB file, there is technically only one column for chain IDs, although ChimeraX will also accept using two columns, but not three. <https://rbvi.ucsf.edu/chimerax/docs/user/formats/pdbintro.html#coords> It may be possible to put 3-character chain IDs in mmCIF (I'm not sure), but it's probably easier to keep using PDB but limit yourself to two characters. 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 Jun 10, 2026, at 9:43 AM, Parvate, Amar D via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:
Hi My name is Amar and I am working on the structure of a phage tail complex. I have multiple dodecameric assemblies within the tail complex. Is there a way to change/name chain IDs from say P1 to P12 in chimeraX so that they are all read and rendered? Can I make ChimeraX read chains beyond P9 when I have numbered them from say P1 to P12? Coot reads it fine but ChimeraX gets confused after P9 (image attached). I cannot select chain “P12” or any residue/sidechain in it<image001.png> Best Amar