2Z97:
reference: A role of the heme-7-propionate side chain in cytochrome P450cam as a gate for regulating the access of water molecules to the substrate-binding site., Hayashi T, Harada K, Sakurai K, Shimada H, Hirota S, J Am Chem Soc. 2009 Feb 4;131(4):1398-400. PMID: 19133773

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