Redox-Linked Domain Movements in the Catalytic Cycle of Cytochrome P450 Reductase

NADPH-cytochrome P450 reductase is a key component of the P450 mono-oxygenase drug-metabolizing system. There is evidence for a conformational equilibrium involving large-scale domain motions in this enzyme. We now show, using small-angle X-ray scattering (SAXS) and small-angle neutron scattering, t...

Full description

Saved in:
Bibliographic Details
Published in:Structure (London) 2013-09, Vol.21 (9), p.1581-1589
Main Authors: Huang, Wei-Cheng, Ellis, Jacqueline, Moody, Peter C.E., Raven, Emma L., Roberts, Gordon C.K.
Format: Article
Language:English
Subjects:
Biocatalysis
Catalytic Domain
Flavin Mononucleotide - chemistry
Humans
Kinetics
Models, Molecular
NADP - chemistry
NADPH-Ferrihemoprotein Reductase - chemistry
Oxidation-Reduction
Protein Binding
Protein Structure, Secondary
Scattering, Small Angle
X-Ray Diffraction
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:NADPH-cytochrome P450 reductase is a key component of the P450 mono-oxygenase drug-metabolizing system. There is evidence for a conformational equilibrium involving large-scale domain motions in this enzyme. We now show, using small-angle X-ray scattering (SAXS) and small-angle neutron scattering, that delivery of two electrons to cytochrome P450 reductase leads to a shift in this equilibrium from a compact form, similar to the crystal structure, toward an extended form, while coenzyme binding favors the compact form. We present a model for the extended form of the enzyme based on nuclear magnetic resonance and SAXS data. Using the effects of changes in solution conditions and of site-directed mutagenesis, we demonstrate that the conversion to the extended form leads to an enhanced ability to transfer electrons to cytochrome c. This structural evidence shows that domain motion is linked closely to the individual steps of the catalytic cycle of cytochrome P450 reductase, and we propose a mechanism for this. [Display omitted] •Cytochrome P450 reductase is in equilibrium between compact and extended forms•The position of the equilibrium depends on the redox state of the enzyme•The extended form favors electron transfer to cytochrome c•Domain motion is linked closely to the individual steps of the catalytic cycle Solution scattering experiments by Huang et al. connect domain movement in cytochrome P450 reductase to individual steps in the catalytic cycle. The domain movement necessary for enzyme turnover is not achieved simply by random diffusion; rather, it is linked closely to the individual steps of the catalytic cycle.
ISSN:0969-2126
1878-4186
DOI:10.1016/j.str.2013.06.022