title: Effects of membrane mimetics on cytochrome P450-cytochrome b5 interactions characterized by NMR spectroscopy.
abstract: Mammalian cytochrome P450 (P450) is a membrane-bound monooxygenase whose catalytic activities require two electrons to be sequentially delivered from its redox partners: cytochrome b5 (cytb5) and cytochrome P450 reductase, both of which are membrane proteins. Although P450 functional activities are known to be affected by lipids, experimental evidence to reveal the effect of membrane on P450-cytb5 interactions is still lacking. Here, we present evidence for the influence of phospholipid bilayers on complex formation between rabbit P450 2B4 (CYP2B4) and rabbit cytb5 at the atomic level, utilizing NMR techniques. General line broadening and modest chemical shift perturbations of cytb5 resonances characterize CYP2B4-cytb5 interactions on the intermediate time scale. More significant intensity attenuation and a more specific protein-protein binding interface are observed in bicelles as compared with lipid-free solution, highlighting the importance of the lipid bilayer in stabilizing stronger and more specific interactions between CYP2B4 and cytb5, which may lead to a more efficient electron transfer. Similar results observed for the interactions between CYP2B4 lacking the transmembrane domain (tr-CYP2B4) and cytb5 imply interactions between tr-CYP2B4 and the membrane surface, which might assist in CYP2B4-cytb5 complex formation by orienting tr-CYP2B4 for efficient contact with cytb5. Furthermore, the observation of weak and nonspecific interactions between CYP2B4 and cytb5 in micelles suggests that lipid bilayer structures and low curvature membrane surface are preferable for CYP2B4-cytb5 complex formation. Results presented in this study provide structural insights into the mechanism behind the important role that the lipid bilayer plays in the interactions between P450s and their redox partners.
authors: From the Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and.
authors: Meng
authors: M
authors: Zhang
authors: From the Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and.
authors: Rui
authors: R
authors: Huang
authors: the Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105.
authors: Sang-Choul
authors: SC
authors: Im
authors: the Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105.
authors: Lucy
authors: L
authors: Waskell
authors: From the Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and ramamoor@umich.edu.
authors: Ayyalusamy
authors: A
authors: Ramamoorthy
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D040761:Biomimetic Materials / Q000737:chemistry*; D002462:Cell Membrane; D000072467:Cytochrome P450 Family 2; D015786:Cytochromes b5 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004579:Electron Transport / Q000502:physiology; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011817:Rabbits
chemical_list: D008565:Membrane Proteins; D009097:Multienzyme Complexes; D015786:Cytochromes b5; D001189:Aryl Hydrocarbon Hydroxylases; D000072467:Cytochrome P450 Family 2; C465241:cytochrome P-450 CYP2B4 (rabbit)
keywords: cytochrome P450; cytochrome b5; lipid bilayer; membrane bilayer; membrane protein; nuclear magnetic resonance (NMR)