1KEM:
reference: Insights into antibody catalysis: structure of an oxygenation catalyst at 1.9-angstrom resolution., Hsieh-Wilson LC, Schultz PG, Stevens RC, Proc Natl Acad Sci U S A 1996 May 28;93(11):5363-7. PMID: 8643580

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