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Structural basis for effector control and redox partner recognition in cytochrome P450.
Sarvind Tripathi1, Huiying Li, Thomas L Poulos
1Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697-3900, USA.
Science (New York, N.Y.)
|June 8, 2013
Summary
The structure of cytochrome P450cam complexed with putidaredoxin reveals how electron transfer is regulated. Putidaredoxin shifts P450cam to an open state, facilitating proton-coupled electron transfer.
Area of Science:
- Biochemistry
- Structural Biology
- Enzymology
Background:
- Cytochromes P450 are crucial enzymes for monooxygenase reactions.
- Electron transfer from redox partners is essential for P450 activity.
- Structural data on P450-redox partner complexes are limited, hindering understanding of interaction control.
Purpose of the Study:
- To elucidate the structural basis of P450-redox partner interactions.
- To understand the role of putidaredoxin (Pdx) in regulating P450cam activity.
Main Methods:
- X-ray crystallography was used to determine the structures of oxidized and reduced P450cam complexed with Pdx.
- High-resolution structures were obtained at 2.2 and 2.09 angstroms.
Main Results:
- The crystal structure revealed that Pdx favors an open conformation of P450cam, contrary to expectations.
- This open state facilitates the formation of a water-mediated hydrogen-bonded network.
- This network is critical for enabling proton-coupled electron transfer.
Conclusions:
- Putidaredoxin acts as an effector, inducing an open conformation in P450cam.
- The Pdx-induced open state is essential for the proton-coupled electron transfer mechanism in P450cam.
- These findings provide critical structural insights into P450-redox partner complex regulation.
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