I’m adding metadata to a large set of mmCIF files coming from a large-scale AlphaFold prediction effort. The goal is to have descriptions for each polypeptide chain visible when opening the file in ChimeraX. Adding descriptions is easy via the _entity.pdbx_description parameter. However, I can’t figure out how to add UniProt IDs so they show up in their own column, which is usually the case for files I’ve downloaded from the AlphaFold database or PDB. I’ve tried editing struct_ref and struct_ref_seq , but ChimeraX still won’t display the UniProt IDs. How do I do this?