XmlmmCIF equivalent: struct_sheet Data items in the STRUCT_SHEET category record details about the beta sheets. XmlmmCIF equivalent: struct_sheet/details A description of special aspects of the beta-sheet. XmlmmCIF equivalent: struct_sheet/number_strands The number of strands in the sheet. If a given range of residues is bulged out from the strands, it is still counted as one strand. If a strand is composed of two different regions of polypeptide, it is still counted as one strand, so long as the proper hydrogen bonding connections are made to adjacent strands. XmlmmCIF equivalent: struct_sheet/type A simple descriptor for the type of the sheet. XmlmmCIF equivalent: struct_sheet/id The value of _struct_sheet.id must uniquely identify a record in the STRUCT_SHEET list. Note that this item need not be a number; it can be any unique identifier.