1OGX:
reference: Detection of large pKa perturbations of an inhibitor and a catalytic group at an enzyme active site, a mechanistic basis for catalytic power of many enzymes., Ha NC, Kim MS, Lee W, Choi KY, Oh BH, J Biol Chem. 2000 Dec 29;275(52):41100-6. PMID: 11007792

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