6MJM:
reference: Active site differences between substrate-free and ritonavir-bound cytochrome P450 (CYP) 3A5 reveal plasticity differences between CYP3A5 and CYP3A4., Hsu MH, Johnson EF, J Biol Chem. 2019 Mar 29. pii: RA119.007928. doi: 10.1074/jbc.RA119.007928. PMID: 30926609

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