title: Conformational selectivity in cytochrome P450 redox partner interactions.
abstract: The heme iron of cytochromes P450 must be reduced to bind and activate molecular oxygen for substrate oxidation. Reducing equivalents are derived from a redox partner, which requires the formation of a protein-protein complex. A subject of increasing discussion is the role that redox partner binding plays, if any, in favoring significant structural changes in the P450s that are required for activity. Many P450s now have been shown to experience large open and closed motions. Several structural and spectral studies indicate that the well-studied P450cam adopts the open conformation when its redox partner, putidaredoxin (Pdx), binds, whereas recent NMR studies indicate that this view is incorrect. Given the relevance of this discrepancy to P450 chemistry, it is important to determine whether Pdx favors the open or closed form of P450cam. Here, we have used both computational and experimental isothermal titration calorimetry studies that unequivocally show Pdx favors binding to the open form of P450cam. Analyses of molecular-dynamic trajectories also provide insights into intermediate conformational states that could be relevant to catalysis.
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697; Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697; Department of Chemistry, University of California, Irvine, CA 92697.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Hollingsworth
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697; Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697; Department of Chemistry, University of California, Irvine, CA 92697.
authors.forename: Dipanwita
authors.initials: D
authors.lastname: Batabyal
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697; Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697; Department of Chemistry, University of California, Irvine, CA 92697.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Nguyen
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697; Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697; Department of Chemistry, University of California, Irvine, CA 92697 poulos@uci.edu.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Poulos
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D002151:Calorimetry / Q000379:methods; D019475:Camphor 5-Monooxygenase / Q000737:chemistry / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000378:metabolism; D005288:Ferredoxins / Q000737:chemistry / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D016958:Pseudomonas putida / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D005288:Ferredoxins; C100137:putidaredoxin; D003577:Cytochrome P-450 Enzyme System; D019475:Camphor 5-Monooxygenase
keywords: P450; conformation; redox partner