Geometrical criteria for characterizing open and closed states of WPD-loop in PTP1B

► 118 structures of PTP1B were collected from RCSB protein data bank. ► Structures studied for conformational differences. ► Five novel hydrogen bonds were found to be specific to the closed PTP1B structures. ► Steric clashes between residues leads to the rearrangement of WPD loop and formation of hydrogen bonds.