2FFY:
reference: The deacylation mechanism of AmpC beta-lactamase at ultrahigh resolution., Chen Y, Minasov G, Roth TA, Prati F, Shoichet BK, J Am Chem Soc. 2006 Mar 8;128(9):2970-6. PMID: 16506777

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