          Data items in the PDBX_STRUCT_SHEET_HBOND category record details\
           about the hydrogen bonding between residue ranges in a beta sheet.\
           This category is provided for cases where only a single hydrogen\
           bond is used to register the two residue ranges.   Category\
           STRUCT_SHEET_HBOND should be used when the initial and terminal\
           hydrogen bonds for strand pair are known. \
