1IYS:
reference: Crystal structure of extended-spectrum beta-lactamase Toho-1: insights into the molecular mechanism for catalytic reaction and substrate specificity expansion., Ibuka AS, Ishii Y, Galleni M, Ishiguro M, Yamaguchi K, Frere JM, Matsuzawa H, Sakai H, Biochemistry 2003 Sep 16;42(36):10634-43. PMID: 12962487

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).