An optional identifier of the second of the three atom sites
that define the angle specified by _geom_angle.value.
This data item is a pointer to _atom_site.auth_atom_id in the
ATOM_SITE category.
This HTML dictionary was created using the CIFLIB C Language Application Program Interface
at the
Nucleic Acid Database Project
Rutgers University, Department of Chemistry
New Brunswick, New Jersey ndbadmin@ndbserver.rutgers.edu