A catalytic dyad modulates conformational change in the CO 2 -fixing flavoenzyme 2-ketopropyl coenzyme M oxidoreductase/carboxylase.

Autor: Mattice JR; Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA., Shisler KA; Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA., DuBois JL; Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA., Peters JW; Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA., Bothner B; Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA. Electronic address: bbothner@montana.edu.
Jazyk: angličtina
Zdroj: The Journal of biological chemistry [J Biol Chem] 2022 May; Vol. 298 (5), pp. 101884. Date of Electronic Publication: 2022 Mar 31.
DOI: 10.1016/j.jbc.2022.101884
Abstrakt: 2-Ketopropyl-coenzyme M oxidoreductase/carboxylase (2-KPCC) is a member of the flavin and cysteine disulfide containing oxidoreductase family (DSOR) that catalyzes the unique reaction between atmospheric CO 2 and a ketone/enolate nucleophile to generate acetoacetate. However, the mechanism of this reaction is not well understood. Here, we present evidence that 2-KPCC, in contrast to the well-characterized DSOR enzyme glutathione reductase, undergoes conformational changes during catalysis. Using a suite of biophysical techniques including limited proteolysis, differential scanning fluorimetry, and native mass spectrometry in the presence of substrates and inhibitors, we observed conformational differences between different ligand-bound 2-KPCC species within the catalytic cycle. Analysis of site-specific amino acid variants indicated that 2-KPCC-defining residues, Phe501-His506, within the active site are important for transducing these ligand induced conformational changes. We propose that these conformational changes promote substrate discrimination between H + and CO 2 to favor the metabolically preferred carboxylation product, acetoacetate.
Competing Interests: Conflict of interest The authors declare that they have no conflict of interest with the contents of this article.
(Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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