Chain length-dependent cooperativity in fatty acid binding and oxidation by cytochrome P450BM3 (CYP102A1).
10.1007/s13238-011-1082-6
- Author:
Benjamin ROWLATT
1
;
Jake A YORKE
;
Anthony J STRONG
;
Christopher J C WHITEHOUSE
;
Stephen G BELL
;
Luet-Lok WONG
Author Information
1. Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, UK.
- Publication Type:Journal Article
- MeSH:
Bacterial Proteins;
metabolism;
Cytochrome P-450 Enzyme System;
metabolism;
Fatty Acids;
chemistry;
metabolism;
Lauric Acids;
chemistry;
metabolism;
Myristic Acid;
chemistry;
metabolism;
NADPH-Ferrihemoprotein Reductase;
metabolism;
Osmolar Concentration;
Oxidation-Reduction;
Palmitic Acid;
chemistry;
metabolism;
Structure-Activity Relationship
- From:
Protein & Cell
2011;2(8):656-671
- CountryChina
- Language:English
-
Abstract:
Fatty acid binding and oxidation kinetics for wild type P450(BM3) (CYP102A1) from Bacillus megaterium have been found to display chain length-dependent homotropic behavior. Laurate and 13-methyl-myristate display Michaelis-Menten behavior while there are slight deviations with myristate at low ionic strengths. Palmitate shows Michaelis-Menten kinetics and hyperbolic binding behavior in 100 mmol/L phosphate, pH 7.4, but sigmoidal kinetics (with an apparent intercept) in low ionic strength buffers and at physiological phosphate concentrations. In low ionic strength buffers both the heme domain and the full-length enzyme show complex palmitate binding behavior that indicates a minimum of four fatty acid binding sites, with high cooperativity for the binding of the fourth palmitate molecule, and the full-length enzyme showing tighter palmitate binding than the heme domain. The first flavin-to-heme electron transfer is faster for laurate, myristate and palmitate in 100 mmol/L phosphate than in 50 mmol/L Tris (pH 7.4), yet each substrate induces similar high-spin heme content. For palmitate in low phosphate buffer concentrations, the rate constant of the first electron transfer is much larger than k (cat). The results suggest that phosphate has a specific effect in promoting the first electron transfer step, and that P450(BM3) could modulate Bacillus membrane morphology and fluidity via palmitate oxidation in response to the external phosphate concentration.
