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

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journal contribution
posted on 10.09.2013, 09:08 by Wei-Cheng Huang, Jacqueline Ellis, Peter C.E. Moody, Emma L. Raven, Gordon C.K. Roberts
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.

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Citation

Structure, 2013, 21 (9), pp. 1581-1589

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Biological Sciences/Department of Biochemistry

Version

VoR (Version of Record)

Published in

Structure

Publisher

Elsevier (Cell Press)

issn

0969-2126

eissn

1878-4186

Copyright date

2013

Available date

10/09/2013

Publisher version

http://www.sciencedirect.com/science/article/pii/S0969212613002463

Language

en

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