1BLH:
reference: Structure of a phosphonate-inhibited beta-lactamase. An analog of the tetrahedral transition state/intermediate of beta-lactam hydrolysis., Chen CC, Rahil J, Pratt RF, Herzberg O, J Mol Biol 1993 Nov 5;234(1):165-78. PMID: 8230196

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