Structural Basis for Effector Control and Redox Partner Recognition in Cytochrome P450

Abstract

Getting Active The P450 cytochromes are a family of enzymes that contain a heme cofactor and catalyze the oxidation of organic substrates, including drugs. Protein partners are required to deliver electrons to P450. Insight into this mechanism has come from studies of bacterial P450cam; however, a lack of structures of redox complexes has hindered understanding. Tripathi et al. (p. 1227 ) describe the high resolution crystal structures of oxidized and reduced P450cam complexed with its redox partner putidaredoxin (Pdx). Pdx favors binding to the more open form of P450cam, which enables establishment of the water-mediated H-bonded network required for proton-coupled electron transfer and O 2 activation.