Reaction Mechanism Catalyzed by the Dissimilatory Sulfite Reductase - The Role of the Siroheme-[4FeS4] Cofactor.

Autor: Wójcik-Augustyn A; Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, ul. Gronostajowa 7, 30-387, Cracow, Poland., Johansson AJ; Swedish Nuclear Fuel and Waste Management Co (SKB), Box 3091, 169 03, Solna, Sweden., Borowski T; Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239, Cracow, Poland.
Jazyk: angličtina
Zdroj: Chemphyschem : a European journal of chemical physics and physical chemistry [Chemphyschem] 2024 Jul 15; Vol. 25 (14), pp. e202400327. Date of Electronic Publication: 2024 May 18.
DOI: 10.1002/cphc.202400327
Abstrakt: The present work is another part of our investigation on the pathway of dissimilatory sulfate reduction and covers a theoretical study on the reaction catalyzed by dissimilatory sulfite reductase (dSIR). dSIR is the terminal enzyme involved in this metabolic pathway, which uses the siroheme-[4Fe4S] cofactor for six-electron reduction of sulfite to sulfide. In this study we use a large cluster model containing siroheme-[4Fe4S] cofactor and protein residues involved in the direct interactions with the substrate, to get insight into the most feasible reaction mechanism and to understand the role of each considered active site component. In combination with earlier studies reported in the literature, our results lead to several interesting insights. One of the most important conclusions is that the reaction mechanism consists of three steps of two-electron reduction of sulfur and the probable role of the siroheme-[4Fe4S] cofactor is to ensure the delivery of packages of two electrons to the reactant.
(© 2024 Wiley-VCH GmbH.)
Databáze: MEDLINE
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