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Biosynthesis of a Central Intermediate in Hydrogen Sulfide Metabolism by a Novel Human Sulfurtransferase and Its Yeast Ortholog

[Image: see text] Human sulfide:quinone oxidoreductase (SQOR) catalyzes the conversion of H(2)S to thiosulfate, the first step in mammalian H(2)S metabolism. SQOR’s inability to produce the glutathione persulfide (GSS(–)) substrate for sulfur dioxygenase (SDO) suggested that a thiosulfate:glutathion...

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Autores principales: Melideo, Scott L., Jackson, Michael R., Jorns, Marilyn Schuman
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2014
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4108183/
https://www.ncbi.nlm.nih.gov/pubmed/24981631
http://dx.doi.org/10.1021/bi500650h
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author Melideo, Scott L.
Jackson, Michael R.
Jorns, Marilyn Schuman
author_facet Melideo, Scott L.
Jackson, Michael R.
Jorns, Marilyn Schuman
author_sort Melideo, Scott L.
collection PubMed
description [Image: see text] Human sulfide:quinone oxidoreductase (SQOR) catalyzes the conversion of H(2)S to thiosulfate, the first step in mammalian H(2)S metabolism. SQOR’s inability to produce the glutathione persulfide (GSS(–)) substrate for sulfur dioxygenase (SDO) suggested that a thiosulfate:glutathione sulfurtransferase (TST) was required to provide the missing link between the SQOR and SDO reactions. Although TST could be purified from yeast, attempts to isolate the mammalian enzyme were not successful. We used bioinformatic approaches to identify genes likely to encode human TST (TSTD1) and its yeast ortholog (RDL1). Recombinant TSTD1 and RDL1 catalyze a predicted thiosulfate-dependent conversion of glutathione to GSS(–). Both enzymes contain a rhodanese homology domain and a single catalytically essential cysteine, which is converted to cysteine persulfide upon reaction with thiosulfate. GSS(–) is a potent inhibitor of TSTD1 and RDL1, as judged by initial rate accelerations and ≥25-fold lower K(m) values for glutathione observed in the presence of SDO. The combined action of GSS(–) and SDO is likely to regulate the biosynthesis of the reactive metabolite. SDO drives to completion p-toluenethiosulfonate:glutathione sulfurtransferase reactions catalyzed by TSTD1 and RDL1. The thermodynamic coupling of the irreversible SDO and reversible TST reactions provides a model for the physiologically relevant reaction with thiosulfate as the sulfane donor. The discovery of bacterial Rosetta Stone proteins that comprise fusions of SDO and TSTD1 provides phylogenetic evidence of the association of these enzymes. The presence of adjacent bacterial genes encoding SDO–TSTD1 fusion proteins and human-like SQORs suggests these prokaryotes and mammals exhibit strikingly similar pathways for H(2)S metabolism.
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spelling pubmed-41081832015-07-01 Biosynthesis of a Central Intermediate in Hydrogen Sulfide Metabolism by a Novel Human Sulfurtransferase and Its Yeast Ortholog Melideo, Scott L. Jackson, Michael R. Jorns, Marilyn Schuman Biochemistry [Image: see text] Human sulfide:quinone oxidoreductase (SQOR) catalyzes the conversion of H(2)S to thiosulfate, the first step in mammalian H(2)S metabolism. SQOR’s inability to produce the glutathione persulfide (GSS(–)) substrate for sulfur dioxygenase (SDO) suggested that a thiosulfate:glutathione sulfurtransferase (TST) was required to provide the missing link between the SQOR and SDO reactions. Although TST could be purified from yeast, attempts to isolate the mammalian enzyme were not successful. We used bioinformatic approaches to identify genes likely to encode human TST (TSTD1) and its yeast ortholog (RDL1). Recombinant TSTD1 and RDL1 catalyze a predicted thiosulfate-dependent conversion of glutathione to GSS(–). Both enzymes contain a rhodanese homology domain and a single catalytically essential cysteine, which is converted to cysteine persulfide upon reaction with thiosulfate. GSS(–) is a potent inhibitor of TSTD1 and RDL1, as judged by initial rate accelerations and ≥25-fold lower K(m) values for glutathione observed in the presence of SDO. The combined action of GSS(–) and SDO is likely to regulate the biosynthesis of the reactive metabolite. SDO drives to completion p-toluenethiosulfonate:glutathione sulfurtransferase reactions catalyzed by TSTD1 and RDL1. The thermodynamic coupling of the irreversible SDO and reversible TST reactions provides a model for the physiologically relevant reaction with thiosulfate as the sulfane donor. The discovery of bacterial Rosetta Stone proteins that comprise fusions of SDO and TSTD1 provides phylogenetic evidence of the association of these enzymes. The presence of adjacent bacterial genes encoding SDO–TSTD1 fusion proteins and human-like SQORs suggests these prokaryotes and mammals exhibit strikingly similar pathways for H(2)S metabolism. American Chemical Society 2014-07-01 2014-07-22 /pmc/articles/PMC4108183/ /pubmed/24981631 http://dx.doi.org/10.1021/bi500650h Text en Copyright © 2014 American Chemical Society Terms of Use (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html)
spellingShingle Melideo, Scott L.
Jackson, Michael R.
Jorns, Marilyn Schuman
Biosynthesis of a Central Intermediate in Hydrogen Sulfide Metabolism by a Novel Human Sulfurtransferase and Its Yeast Ortholog
title Biosynthesis of a Central Intermediate in Hydrogen Sulfide Metabolism by a Novel Human Sulfurtransferase and Its Yeast Ortholog
title_full Biosynthesis of a Central Intermediate in Hydrogen Sulfide Metabolism by a Novel Human Sulfurtransferase and Its Yeast Ortholog
title_fullStr Biosynthesis of a Central Intermediate in Hydrogen Sulfide Metabolism by a Novel Human Sulfurtransferase and Its Yeast Ortholog
title_full_unstemmed Biosynthesis of a Central Intermediate in Hydrogen Sulfide Metabolism by a Novel Human Sulfurtransferase and Its Yeast Ortholog
title_short Biosynthesis of a Central Intermediate in Hydrogen Sulfide Metabolism by a Novel Human Sulfurtransferase and Its Yeast Ortholog
title_sort biosynthesis of a central intermediate in hydrogen sulfide metabolism by a novel human sulfurtransferase and its yeast ortholog
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4108183/
https://www.ncbi.nlm.nih.gov/pubmed/24981631
http://dx.doi.org/10.1021/bi500650h
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