Báo cáo khoa học: Interflavin electron transfer in human cytochrome P450 reductase is enhanced by coenzyme binding

Interflavin electron transfer in human cytochrome P450 reductase is enhanced by coenzyme binding

Tác giả: Aldo Gutierrez, Andrew W. Munro, Alex Grunau, C. Roland Wolf, Nigel S. Scrutton, and Gordon C. K. Roberts

Lĩnh vực: Biochemistry, Biological NMR Centre, Biomedical Research Centre

Nội dung tài liệu: This study investigates the role of coenzyme binding in regulating interflavin electron transfer within human cytochrome P450 reductase (CPR) using temperature-jump spectroscopy. The research indicates that NADPH binding, particularly the 2′-phosphate moiety, significantly enhances the rate of internal electron transfer. Experiments with NADH and fragments of nicotinamide coenzymes, such as 2′,5′-ADP and 2′-AMP, reveal that these ligands also increase the electron transfer rate, albeit to varying degrees. The study suggests that coenzyme binding induces conformational changes that optimize electron transfer between flavin cofactors, without altering their redox potentials. This work contributes to understanding the complex regulation of electron transfer in CPR and highlights the importance of conformational gating in biological electron transfer reactions.

Mục lục chi tiết:

• Experimental procedures
• Materials
• Protein purification
• Temperature-jump and stopped-flow kinetic methods
• Inhibition studies
• Potentiometric titrations
• Results
• Chemical relaxation reactions with NADH-reduced CPR
• Binding of adenosine 2′,5′-bisphosphate to CPR and effects on interflavin electron transfer
• Effects of binding adenosine 2′,5′-bisphosphate on hydride ion transfer
• The role of W676 in interdomain electron transfer
• Discussion
• Acknowledgements
• References