Polymorphic Variants of Human Rhodanese Exhibit Differences in Thermal Stability and Sulfur Transfer Kinetics

Libiad, Marouane; Sriraman, Anusha; Banerjee, Ruma

doi:10.1074/jbc.m115.675694

Cited by 56 publications

(66 citation statements)

References 43 publications

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“…The activity of MPST and the prevalence of its isoforms was assessed in murine liver, kidney and brain. Since the thiophilic acceptors, cysteine, homocysteine and GSH can stimulate H2S production (8,9) or consumption (28,29) by other enzymes present in tissue homogenates, DHLA was used as the thiophilic acceptor to assess MPST activity. A 10-fold range in tissue MPST activity was seen using either the lead sulfide or the gas chromatography (GC)-based sulfur chemiluminescence detection assay.…”

Section: Mpst Activity In Murine Tissuementioning

confidence: 99%

Thioredoxin regulates human mercaptopyruvate sulfurtransferase at physiologically-relevant concentrations

Yadav

Vitvitsky

Carballal

et al. 2020

Journal of Biological Chemistry

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3-Mercaptopyruvate sulfur transferase (MPST) catalyzesthe desulfuration of 3mercaptopyruvate (3-MP) and transfers sulfane sulfur from an enzyme-bound persulfide intermediate to thiophilic acceptors such as thioredoxin and cysteine. Hydrogen sulfide (H2S), a signaling molecule implicated in many physiological processes, can be released from the persulfide product of the MPST reaction. Two splice variants of MPST, differing by 20 amino acids at the N-terminus, give rise to the cytosolic MPST1 and mitochondrial MPST2 isoforms. Here, we characterized the poorly studied MPST1 variant and demonstrated that substitutions in its Ser-His-Asp triad, proposed to serve a general acid-base role, minimally affect catalytic activity. We estimated the 3-MP concentration in murine liver, kidney and brain tissues, finding that it ranges from 0.4 μmol•kg -1 in brain to 1.4 μmol•kg -1 in kidney. We also show that N-acetylcysteine, a widely used antioxidant, is a poor substrate for MPST and unlikely to function as a thiophilic acceptor. Thioredoxin exhibits substrate inhibition, increasing the KM for 3-MP ~15-fold compared with other sulfur acceptors. Kinetic simulations at physiologically relevant substrate concentrations predicted that the proportion of sulfur transfer to thioredoxin increases ~3.5-fold as its concentration decreases from 10 to 1 µM, while the total MPST reaction 1 H2S: hydrogen sulfide, MPST: mercaptopyruvate sulfur transferase; 3-MP: 3-mercaptopyruvate; rate increases ~7-fold. The simulations also predicted that cysteine is a quantitatively significant sulfane sulfur acceptor, revealing MPST's potential to generate low molecular weight persulfides. We conclude that the MPST1 and 2 isoforms are kinetically indistinguishable and that thioredoxin modulates the MPSTcatalyzed reaction in a physiologically relevant concentration range.

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Section: Mpst Activity In Murine Tissuementioning

confidence: 99%

Thioredoxin regulates human mercaptopyruvate sulfurtransferase at physiologically-relevant concentrations

Yadav

Vitvitsky

Carballal

et al. 2020

Journal of Biological Chemistry

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“…H 2 S is produced endogenously by two enzymes in the transsulfuration pathway, cystathionine β-synthase and γ-cystathionase as well as by mercaptopyruvate sulfurtransferase (MST) (10)(11)(12)(13). H 2 S is oxidized via the sulfide oxidation pathway to generate the end-products thiosulfate and sulfate via the concerted action of the mitochondrial enzymes sulfide quinone oxidoreductase, persulfide dioxygenase, rhodanese and sulfite oxidase (14)(15)(16).…”

Section: Hydrogen Sulfide (H 2 S)mentioning

confidence: 99%

“…In some members, only a single rhodanese domain is present such as in the bacterial GlpE (21) and human TSTD1 (22). Alternatively, the rhodanese domain can be present in a tandem repeat, as in rhodanese and MST, where the active sites are located in a cleft between the N-and C-terminal domains (14,15). Finally, rhodanese domains are fused to other protein domains as in Cdc25 phosphatase (20) or in the PRF and CstB proteins (23,24).…”

Section: Hydrogen Sulfide (H 2 S)mentioning

confidence: 99%

Section: Hydrogen Sulfide (H 2 S)mentioning

confidence: 99%

“…Human rhodanese preferentially catalyzes sulfur transfer from GSSH to sulfite forming thiosulfate and GSH (eq. 1), and exhibits a >2 ×10 5 -fold preference for this, over the reverse reaction (14,15).Residues on an active site loop containing the cysteine at which the Cys-SSH intermediate is formed are predicted to confer substrate specificity (Fig. 1A).…”

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Thiosulfate sulfurtransferase-like domain–containing 1 protein interacts with thioredoxin

Libiad

Motl

Akey

et al. 2018

Journal of Biological Chemistry

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ǂ These authors contributed equally to this work Rhodanese domains are structural modules present in the sulfurtransferase superfamily. These domains can exist as single units, in tandem repeats or fused to domains with other activities. Despite their prevalence across species, the specific physiological roles of most sulfurtransferases are not known. Mammalian rhodanese and mercaptopyruvate sulfurtransferase are perhaps the best-studied members of this protein superfamily and are involved in hydrogen sulfide metabolism. The relatively unstudied human thiosulfate sulfurtransferase like domain-containing 1 (TSTD1) protein, a single-domain cytoplasmic sulfurtransferase, was also postulated to play a role in the sulfide oxidation pathway using thiosulfate to form glutathione persulfide, for subsequent processing in the mitochondrial matrix. Prior kinetic analysis of TSTD1 was performed at pH 9.2, raising questions about relevance and the proposed model for TSTD1 function. In this study, we report a 1.04 Å resolution crystal structure of human TSTD1, which displays an exposed active site that is distinct from that of rhodanese and mercaptopyruvate sulfurtransferase. Kinetic studies with a combination of sulfur donors and acceptors reveal that TSTD1 exhibits a low K M for thioredoxin as a sulfane sulfur acceptor and that it utilizes thiosulfate inefficiently as a sulfur donor. The active site exposure and its interaction with thioredoxin, suggest that TSTD1 might play a role in sulfide-based signaling. The apical localization of TSTD1 in human colonic crypts, which interfaces with sulfide-releasing microbes, and the overexpression of TSTD1 in colon cancer, provides potentially intriguing clues as to its role in sulfide metabolism. Hydrogen sulfide (H 2 S)1 is an important signaling molecule with effects on multiple physiological processes including neuromodulation, inflammation and cardiac function (1-7). Maintaining healthy levels of H 2 S in mammalian cells requires tight control of its biosynthesis and its catabolism (8,9). H 2 S is produced endogenously by two enzymes in the transsulfuration pathway, cystathionine β-synthase and γ-cystathionase as well as by mercaptopyruvate sulfurtransferase (MST) (10-13). H 2 S is oxidized via the sulfide oxidation pathway to generate the end-products thiosulfate Protein persulfidation, a posttranslational modification of cysteine residues, is postulated to be a major mechanism by which H 2 S signals (17). However, the mechanism by which target proteins acquire this modification and the sulfur source(s) used in persulfidation reactions are unclear (18). Sulfurtransferases like rhodanese or the single rhodanese domain containing TSTD1 could potentially play a role in protein persulfidation because of their capacity to form an active site cysteine persulfide during their reaction cycle (18).The rhodanese superfamily members are distinguished by a structural module with an α/β topology in which α-helices surround a central five-stranded β-sheet core (19). At least three variations...

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Hydrogen Sulfide Oxidation by Sulfide Quinone Oxidoreductase

2020

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Hydrogen sulfide (H2S) is an environmental toxin and a heritage of ancient microbial metabolism that has stimulated new interest following its discovery as a neuromodulator. While many physiological responses have been attributed to low H2S levels, higher levels inhibit complex IV in the electron transport chain. To prevent respiratory poisoning, a dedicated set of enzymes that make up the mitochondrial sulfide oxidation pathway exists to clear H2S. The committed step in this pathway is catalyzed by sulfide quinone oxidoreductase (SQOR), which couples sulfide oxidation to coenzyme Q10 reduction in the electron transport chain. The SQOR reaction prevents H2S accumulation and generates highly reactive persulfide species as products; these can be further oxidized or can modify cysteine residues in proteins by persulfidation. Here, we review the kinetic and structural characteristics of human SQOR, and how its unconventional redox cofactor configuration and substrate promiscuity lead to sulfide clearance and potentially expand the signaling potential of H2S. This dual role of SQOR makes it a promising target for H2S‐based therapeutics.

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Polymorphic Variants of Human Rhodanese Exhibit Differences in Thermal Stability and Sulfur Transfer Kinetics

Cited by 56 publications

References 43 publications

Thioredoxin regulates human mercaptopyruvate sulfurtransferase at physiologically-relevant concentrations

Thioredoxin regulates human mercaptopyruvate sulfurtransferase at physiologically-relevant concentrations

Thiosulfate sulfurtransferase-like domain–containing 1 protein interacts with thioredoxin

Hydrogen Sulfide Oxidation by Sulfide Quinone Oxidoreductase

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