XmlmmCIF equivalent: struct_sheet_topology Data items in the STRUCT_SHEET_TOPOLOGY category record details about the topology of the residue ranges that form a beta sheet. All topology linkages are pairwise, and the specified pairs are assumed to be successive in the amino acid sequence. These data items are useful in describing various simple and complex folds, but they become inadequate when the strands in the sheet come from more than one chain. One can alternatively use the STRUCT_SHEET_ORDER data items to describe both single and multiple chain-containing sheets. XmlmmCIF equivalent: struct_sheet_topology/offset Designates the relative position in the sheet, plus or minus, of the second residue range to the first. XmlmmCIF equivalent: struct_sheet_topology/sense A flag to indicate whether the two designated residue ranges are parallel or anti-parallel to one another. XmlmmCIF equivalent: struct_sheet_topology/sheet_id This data item is a pointer to _struct_sheet.id in the STRUCT_SHEET category. XmlmmCIF equivalent: struct_sheet_topology/range_id_1 This data item is a pointer to _struct_sheet_range.id in the STRUCT_SHEET_RANGE category. XmlmmCIF equivalent: struct_sheet_topology/range_id_2 This data item is a pointer to _struct_sheet_range.id in the STRUCT_SHEET_RANGE category.