Determination of the Proton Environment of High Stability Menasemiquinone Intermediate in Escherichia coli Nitrate Reductase A by Pulsed EPR

Stéphane Grimaldi (1) , Rodrigo Arias‐cartin (1) , Pascal Lanciano (1) , Sevdalina Lyubenova (1) , Rodolphe Szenes (1) , Burkhard Endeward (1) , Thomas F Prisner (1) , Bruno Guigliarelli (1) , Axel Magalon (2)

1 IMM - Institut de Microbiologie de la Méditerranée
2 IMM - Institut für Metallkunde und Metallphysik

Background: Escherichia coli nitrate reductase A highly stabilizes a semiquinone catalytic intermediate. Results: Three proton hyperfine couplings to this radical with atypical characteristics are characterized. Conclusion: Semiquinone binding is strongly asymmetric and occurs via a single short in-plane H-bond. Significance: Learning how the protein environment tunes the semiquinone properties is crucial for understanding the quinol utilization mechanism by energy-transducing enzymes.

Domaines: Sciences du Vivant [q-bio]

Stéphane Grimaldi, Rodrigo Arias‐cartin, Pascal Lanciano, Sevdalina Lyubenova, Rodolphe Szenes, et al.. Determination of the Proton Environment of High Stability Menasemiquinone Intermediate in Escherichia coli Nitrate Reductase A by Pulsed EPR. Journal of Biological Chemistry, 2012, 287 (7), pp.4662-4670. ⟨10.1074/jbc.M111.325100⟩. ⟨hal-03248799⟩