XmlmmCIF equivalent: struct_ncs_dom Data items in the STRUCT_NCS_DOM category record information about the domains in an ensemble of domains related by one or more non-crystallographic symmetry operators. A domain need not correspond to a completely polypeptide chain; it can be composed of one more more segments in a single chain, or by segments from more than one chain. XmlmmCIF equivalent: struct_ncs_dom/details A description of special aspects of the structural elements that comprise a domain in an ensemble of domains related by non- crystallographic symmetry. XmlmmCIF equivalent: struct_ncs_dom/id The value of _struct_ncs_dom.id must uniquely identify a record in the STRUCT_NCS_DOM list. Note that this item need not be a number; it can be any unique identifier.