The dimeric form of flavocytochrome P450 BM3 is catalytically functional as a fatty acid hydroxylase.
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.
Neeli
Rajasekhar
R
Manchester Interdisciplinary Biocentre, School of Chemical Engineering and Analytical Science, The University of Manchester, Jackson's Mill, UK.
Girvan
Hazel M
HM
Lawrence
Andrew
A
Warren
Martin J
MJ
Leys
David
D
Scrutton
Nigel S
NS
Munro
Andrew W
AW
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
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