1UYU:
reference: A survey of active site access channels in cytochromes P450., Wade RC, Winn PJ, Schlichting I, Sudarko, J Inorg Biochem. 2004 Jul;98(7):1175-82. PMID: 15219983

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