3ZHH:
reference: Directed Evolution of Mycobacterium tuberculosis beta-Lactamase Reveals Gatekeeper Residue That Regulates Antibiotic Resistance and Catalytic Efficiency., Feiler C, Fisher AC, Boock JT, Marrichi MJ, Wright L, Schmidpeter PA, Blankenfeldt W, Pavelka M, Delisa MP, PLoS One. 2013 Sep 4;8(9):e73123. doi: 10.1371/journal.pone.0073123. PMID: 24023821

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