title: The dimeric form of flavocytochrome P450 BM3 is catalytically functional as a fatty acid hydroxylase.
abstract: In the model P450 BM3 system, the P450 is fused to its diflavin reductase partner in a single polypeptide. BM3 dimerizes in solution, but the catalytic relevance of the phenomenon was hitherto unknown. We show that BM3 fatty acid hydroxylase specific activity decreases sharply at low enzyme concentrations, consistent with separation of active dimer into inactive monomer. Reductase-dependent specific activities are maintained or enhanced at low concentration, suggesting inter-flavin electron transfer is unaffected. Fatty acid oxidation is reconstituted by mixing inactive oxygenase (A264H) and FMN-depleted (G570D) mutants, demonstrating that inter-monomer (FMN(1)-to-heme(2)) electron transfer supports oxygenase activity in the BM3 dimer.
authors.affiliation: Manchester Interdisciplinary Biocentre, School of Chemical Engineering and Analytical Science, The University of Manchester, Jackson's Mill, UK.
authors.forename: Rajasekhar
authors.initials: R
authors.lastname: Neeli
authors.forename: Hazel M
authors.initials: HM
authors.lastname: Girvan
authors.forename: Andrew
authors.initials: A
authors.lastname: Lawrence
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Warren
authors.forename: David
authors.initials: D
authors.lastname: Leys
authors.forename: Nigel S
authors.initials: NS
authors.lastname: Scrutton
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Munro
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002384:Catalysis; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019281:Dimerization; D004579:Electron Transport; D005227:Fatty Acids / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009251:NADPH-Ferrihemoprotein Reductase; D010084:Oxidation-Reduction
chemical_list: D001426:Bacterial Proteins; D005227:Fatty Acids; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D009251:NADPH-Ferrihemoprotein Reductase; C052423:flavocytochrome P450 BM3 monoxygenases