A component of the identifier for partner 1 of the structure
connection.
This data item is a pointer to _chem_comp_atom.atom_id in the
CHEM_COMP_ATOM category.
Additional Descriptive Information for Depositors
A component of the identifier for partner 1 of
the structure connection. This data item is a
pointer to _chem_comp_atom.atom_id in the CHEM_COMP_ATOM
category.