Binding and Electron Transfer between Putidaredoxin and Cytochrome P450cam. Theory and Experiments

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• 作者：Adrian E. Roitberg ; Marcia J. Holden ; Martin P. Mayhew ; Igor V. Kurnikov ; David N. Beratan ; and Vincent L. Vilker
• 刊名：Journal of the American Chemical Society
• 出版年：1998
• 出版时间：September 9, 1998
• 年：1998
• 卷：120
• 期：35
• 页码：8927 - 8932
• 全文大小：108K
• 年卷期：v.120,no.35(September 9, 1998)
• ISSN：1520-5126

文摘

We present a detailed atomic level view of the interactions between cytochrome P450cam (CYP101)and its natural redox partner, putidaredoxin (Pdx). A combined theoretical (Poisson-Boltzmann electrostaticcalculations, electron transfer pathways, and molecular dynamics) and experimental (site-directed mutagenesisand kinetic analysis) study is used to pinpoint surface residues in both proteins that are important for electrontransfer, binding, or both. We find a situation where the electrostatically complementary regions at the surfaceof both proteins overlap strongly with regions that have large electron transfer couplings to the redox centers.This means that a small surface patch in each protein is involved in binding and electron transfer. A dominantelectron transfer pathway is identified, corresponding to an electron leaving the reduced Fe₂S₂ in Pdx, goingthrough Cys39 and Asp38, and transferring across the interprotein interface to Arg112 (CYP101), then to aheme propionate group, and finally to the heme iron center.