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Publication Abstract from PubMed

Mitochondrial sulfide quinone oxidoreductase (SQR) catalyzes the oxidation of H2S to glutathione persulfide with concomitant reduction of CoQ10. We report herein that the promiscuous activity of human SQR supported the conversion of CoA to CoA-SSH (CoA-persulfide), a potent inhibitor of butyryl-CoA dehydrogenase, and revealed a molecular link between sulfide and butyrate metabolism, which are known to interact. Three different CoQ1-bound crystal structures furnished insights into how diverse substrates access human SQR, and provided snapshots of the reaction coordinate. Unexpectedly, the active site cysteines in SQR are configured in a bridging trisulfide at the start and end of the catalytic cycle, and the presence of sulfane sulfur was confirmed biochemically. Importantly, our study leads to a mechanistic proposal for human SQR in which sulfide addition to the trisulfide cofactor eliminates (201)Cys-SSH, forming an intense charge-transfer complex with flavin adenine dinucleotide, and (379)Cys-SSH, which transfers sulfur to an external acceptor.

A Catalytic Trisulfide in Human Sulfide Quinone Oxidoreductase Catalyzes Coenzyme A Persulfide Synthesis and Inhibits Butyrate Oxidation.,Landry AP, Moon S, Kim H, Yadav PK, Guha A, Cho US, Banerjee R Cell Chem Biol. 2019 Nov 21;26(11):1515-1525.e4. doi:, 10.1016/j.chembiol.2019.09.010. Epub 2019 Oct 4. PMID:31591036^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.