[chimerax-users] label_seq_id in mmcif files for Chimera

[Marcin Wojdyr]

Hi,
I'd like to generate mmCIF files (using my own software) that can be
read by Chimera. The problem is that sometimes I don't know the full
sequence (SEQRES), so I don't know values for _atom_site.label_seq_id.

If I skip label_seq_id entirely, the file doesn't load. ChimeraX gives
warning: "Skipping atom_site category: Missing column 'label_seq_id'".

If I set all label_seq_id values to null ('.') I get warning: "Unable
to infer polymer connectivity due to unspecified label_seq_id for
residue "ARG" near line 125"
and all residues are disconnected.

How should the mmCIF look like so that Chimera infers the connectivity
in the same way as it does for PDB files?

Cheers,
Marcin