Data items in the STRUCT_NCS_DOM category record information
               about the domains in an ensemble of domains related by one or
               more noncrystallographic symmetry operators.
               A domain need not correspond to a complete polypeptide chain;
               it can be composed of one or more segments in a single chain,
               or by segments from more than one chain.
 
    loop_
    _struct_ncs_dom.id
    _struct_ncs_dom.pdbx_ens_id
    _struct_ncs_dom.details
     d1 1  'Chains A, B, and C'
     d2 1  'Chains D, E, and F'