title: Monooxygenation by a thermophilic cytochrome P450 via direct electron donation from NADH.
abstract: The catalysis of cytochrome P450s requires two-electron donation for the activation of an oxygen molecule. Here, we report the enzymatic catalysis of cytochrome P450, CYP119A2 (P450st), from a thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain 7, with NAD(P)H as an electron donor and no redox partners and the crystallographic analysis of P450st at high resolution. P450st can catalyse styrene epoxidation with either NADH or NADPH as an electron donor. The P450st reaction with NADH exhibited a sequential mechanism. X-ray crystallography at a resolution of 1.94 Å revealed a sufficiently large heme pocket for NAD(P)H binding and a novel contiguous channel from the active site to bulk solvent in the distal heme pocket. The narrow channel may transfer protons or water to the heme pocket even when a bulky compound, such as NAD(P)H, binds in the pocket. In addition, the F/G loop region (Leu151-Glu156), located around the substrate channel, was deleted in the mutant and constructed to improve the accessibility of NAD(P)H to the heme pocket. Kinetic properties of the Δ151-156 mutant were compared with those of the wild-type P450st. The K(m) value of the mutant was about 2 times lower than that of the wild-type. The results indicated that NAD(P)H could provide the electrons for P450st within the heme pocket.
authors.affiliation: Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Matsumura
authors.forename: Keisuke
authors.initials: K
authors.lastname: Matsuda
authors.forename: Nobuhumi
authors.initials: N
authors.lastname: Nakamura
authors.forename: Akashi
authors.initials: A
authors.lastname: Ohtaki
authors.forename: Hiromi
authors.initials: H
authors.lastname: Yoshida
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Kamitori
authors.forename: Masafumi
authors.initials: M
authors.lastname: Yohda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohno
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000378:metabolism*; D004579:Electron Transport; D008958:Models, Molecular; D009243:NAD / Q000378:metabolism*; D016944:Sulfolobus / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D009243:NAD; D003577:Cytochrome P-450 Enzyme System; C408874:CYP119 protein, Sulfolobus solfataricus