Structural and Kinetic Studies of Asp632 Mutants and Fully Reduced NADPH-Cytochrome P450 Oxidoreductase Define the Role of Asp632 Loop Dynamics in the Control of NADPH Binding and Hydride Transfer.

ABSTRACT: Conformational changes in NADPH-cytochrome P450 oxidoreductase (CYPOR) associated with electron transfer from NADPH to electron acceptors via FAD and FMN have been investigated via structural studies of the four-electron-reduced NADP⁺-bound enzyme and kinetic and structural studies of mutants that affect the conformation of the mobile Gly631-Asn635 loop (Asp632 loop). The structure of four-electron-reduced, NADP⁺-bound wild type CYPOR shows the plane of the nicotinamide ring positioned perpendicular to the FAD isoalloxazine with its carboxamide group forming H-bonds with N1 of the flavin ring and the Thr535 hydroxyl group. In the reduced enzyme, the C8-C8 atoms of the two flavin rings are ∼1 Å closer than in the fully oxidized and one-electron-reduced structures, whic

SUBMITTER: Xia C 

PROVIDER: S-EPMC5967631 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature