Protonation states of HIS

[brindakv]

HIS occurs in three different protonation states: HIP, HID, and HIE.

Allow the reader to support all 4 residue names (HIS, HIP, HID, and HIE) but make the writer support only HIS to be compliant with PDB conventions.

[benmwebb]

Do you have an example? Has the user explicitly listed protonated histidine in the chem_comp table or are you just dealing with an atom_site table that references these components?

[brindakv]

It is listed in chem_comp, entity_poly, entity_poly_seq, pdbx_poly_seq_scheme, etc. It is also marked as HETATM in atom_site.