XmlmmCIF equivalent: pdbx_entity_src_syn
PDBX_ENTITY_SRC_SYN records the details about each chemically
synthesized molecule (entity) in the asymmetric unit.
XmlmmCIF equivalent: pdbx_entity_src_syn/details
A description of special aspects of the source for the
synthetic entity.
XmlmmCIF equivalent: pdbx_entity_src_syn/entity_id
This data item is a pointer to _entity.id in the ENTITY category.