2WYX:
reference: Neutron Diffraction Studies of a Class A beta-Lactamase Toho-1 E166A/R274N/R276N Triple Mutant., Tomanicek SJ, Blakeley MP, Cooper J, Chen Y, Afonine PV, Coates L, J Mol Biol. 2009 Dec 28. PMID: 20036259

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