Active Intermediates in Copper Nitrite Reductase Reactions Probed by a Cryotrapping‐Electron Paramagnetic Resonance Approach. Issue 33 (4th June 2020)

• Record Type: Journal Article
• Authors: Hedison, Tobias M.; Shanmugam, Muralidharan; Heyes, Derren J.; Edge, Ruth; Scrutton, Nigel S.
• Is Part Of: Angewandte Chemie international edition. Volume 59:Issue 33(2020)
• Page Start: 13936
• Page End: 13940
• Publication Date: 2020-06-04
• Subjects: copper center -- copper nitrite reductase -- electron paramagnetic resonance -- metalloenzymes -- redox enzyme; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202005052
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Redox active metalloenzymes catalyse a range of biochemical processes essential for life. However, due to their complex reaction mechanisms, and often, their poor optical signals, detailed mechanistic understandings of them are limited. Here, we develop a cryoreduction approach coupled to electron paramagnetic resonance measurements to study electron transfer between the copper centers in the copper nitrite reductase (CuNiR) family of enzymes. Unlike alternative methods used to study electron transfer reactions, the cryoreduction approach presented here allows observation of the redox state of both metal centers, a direct read‐out of electron transfer, determines the presence of the substrate/product in the active site and shows the importance of protein motion in inter‐copper electron transfer catalyzed by CuNiRs. Cryoreduction‐EPR is broadly applicable for the study of electron transfer in other redox enzymes and paves the way to explore transient states in multiple redox‐center containing proteins (homo and hetero metal ions). Abstract : Metalloenzyme catalysis : Through the use of cryoreduction and annealing, a method of studying electron transfer in redox active metalloenzymes is developed. Combined with electron paramagnetic resonance spectroscopy, active states in the catalytic cycle of the copper containing nitrite reductases are probed.