1Z8I:
reference: Energetic and structural consequences of perturbing Gly-193 in the oxyanion hole of serine proteases., Bobofchak KM, Pineda AO, Mathews FS, Di Cera E, J Biol Chem 2005 Jul 8;280(27):25644-50. Epub 2005 May 12. PMID: 15890651

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