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Visualizing the protons in a metalloenzyme electron proton transfer pathway

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journal contribution
posted on 25.05.2021, 09:46 by Hanna Kwon, Jaswir Basran, Juliette M Devos, Reynier Suardiaz, Marc W van der Kamp, Adrian J Mulholland, Tobias E Schrader, Andreas Ostermann, Matthew P Blakeley, Peter CE Moody, Emma L Raven
In redox metalloenzymes, the process of electron transfer often involves the concerted movement of a proton. These processes are referred to as proton-coupled electron transfer, and they underpin a wide variety of biological processes, including respiration, energy conversion, photosynthesis, and metalloenzyme catalysis. The mechanisms of proton delivery are incompletely understood, in part due to an absence of information on exact proton locations and hydrogen bonding structures in a bona fide metalloenzyme proton pathway. Here, we present a 2.1-Å neutron crystal structure of the complex formed between a redox metalloenzyme (ascorbate peroxidase) and its reducing substrate (ascorbate). In the neutron structure of the complex, the protonation states of the electron/proton donor (ascorbate) and all of the residues involved in the electron/ proton transfer pathway are directly observed. This information sheds light on possible proton movements during heme-catalyzed oxygen activation, as well as on ascorbate oxidation.

History

Citation

PNAS March 24, 2020 117 (12) 6484-6490; https://doi.org/10.1073/pnas.1918936117

Author affiliation

Department of Molecular and Cell Biology

Version

AM (Accepted Manuscript)

Published in

Proceedings of the National Academy of Sciences of USA

Volume

117

Issue

12

Pagination

6484 - 6490

Publisher

National Academy of Sciences

issn

0027-8424

eissn

1091-6490

Acceptance date

12/02/2020

Copyright date

2020

Available date

25/05/2021

Spatial coverage

United States

Language

English