the enzyme contains 0.22 mol of FAD per mol of protein, when supplemented with exogenous flavin cofactors, the activity of purified CYPOR-mediated cytochrome c reduction is increased
second FMN binding site is detected at the interface of the connecting and FMN binding domains. The two FMN binding sites have different accessibilities to the bulk solvent and different amino acid environments, suggesting stabilization of different electronic structures of the reduced flavin. Since only one FMN cofactor is required for function, a hypothetical mechanism of electron transfer is discussed that proposes shuttling of a single FMN between these two sites coupled with the transition between two semiquinone forms, neutral and anionic
the enzyme contains 0.11 mol of FMN per mol of protein, when supplemented with exogenous flavin cofactors, the activity of purified CYPOR-mediated cytochrome c reduction is increased
NADPH mediates the interaction of CPR with a bilayer that mimics the endoplasmic reticulum. Without NADPH, CPR behaves as a peripheral protein. The introduction of NADPH transforms CPR to an integral membrane protein
CPR is a diflavin protein containing the flavin cofactors FAD, accepting hydride ions from NADPH, and FMN, accepting single electrons from FAD and reducing the heme center of the P450 monooxygenase domain
CPR is a diflavin protein containing the flavin cofactors FAD, accepting hydride ions from NADPH, and FMN, accepting single electrons from FAD and reducing the heme center of the P450 monooxygenase domain
cytochrome P450 reductase is a membrane-bound diflavin protein, which transfers two electrons sequentially from NADPH through FAD to the FMN cofactor, which is the ultimate donor of electrons to cytochrome P450 and other acceptor proteins
FAD accepts a hydride ion from NADPH, and reduced FAD donates electrons to FMN, which in turn transfers electrons to the heme center of cytochrome P450 or NOS oxygenase domain. The FAD and FMN domains are connected by a flexible hinge region, which spans 12 residues from Gly232 to Arg243. The amino acids of the connecting domain are interspersed with the FNR-like domain, (residues 244-266 and 326-450 in rat CYPOR numbering). The connecting domain, composed mainly of alpha-helices, is tightly bound to the FNR-like domain, and together they form the FAD domain, electron transfer mechanism, structure, and redox potentials of the individual redox couples of FAD and FMN of CYPOR, overview
FAD accepts a hydride ion from NADPH, and reduced FAD donates electrons to FMN, which in turn transfers electrons to the heme center of cytochrome P450 oxygenase domain, electron transfer mechanism, structure, and redox potentials of the individual redox couples of FAD and FMN of CYPOR, overview. The FAD and FMN domains are connected by a flexible hinge region. The amino acids of the connecting domain are interspersed with the FNR-like domain. The connecting domain, composed mainly of alpha-helices, is tightly bound to the FNR-like domain, and together they form the FAD domain
the ribityl-nicotinamide moiety of NADP+ rotates, and the nicotinamide ring is stacked on the re-side of the flavin ring poised to transfer hydride ion to the N5 atom of FAD. the AMP-PPi portion of NADP+ binds to the enzyme in the same manner as that observed in the structures of wild-type and W677X, the nicotinamide moiety adopts a very different conformation the AMP-PPi portion of NADP+ binds to the enzyme in the same manner as that observed in the structures of wild-type and W677X, the nicotinamide moiety adopts a very different conformation