scholarly journals A novel deep-sea bacterial threonine dehydratase drives cysteine desulfuration and hydrogen sulfide production

2020 ◽  
Author(s):  
Ning Ma ◽  
Yufan Sun ◽  
Wen Zhang ◽  
Chaomin Sun
Keyword(s):  
Hydrogen Sulfide ◽  
Active Site ◽  
Deep Sea ◽  
Sulfur Source ◽  
Broad Distribution ◽  
Threonine Dehydratase ◽  
Sulfide Production ◽  
Hydrogen Sulfide Production

ABSTRACTCysteine desulfuration is one of the main ways for hydrogen sulfide (H2S) generation in cells and is usually conducted by cystathionine γ-lyase. Herein, we describe a newly discovered deep-sea bacterial threonine dehydratase (psTD), which is surprisingly discovered to drive L-cysteine desulfuration. The mechanisms of psTD catalyzing cysteine desulfuration towards H2S production are first clarified in vitro and in vivo through a combination of genetic and biochemical methods. Furthermore, based on the solved structures of psTD and its various mutants, two or three pockets are found in the active site of psTD, and switch states between inward and outward orientation of a key amino acid R77 determine the open or close status of Pocket III for small molecule exchanges, which further facilitates cysteine desulfuration. Our results reveal the functional diversity and structural specificity of psTD towards L-cysteine desulfuration and H2S formation. Given the broad distribution of psTD homologs in different bacteria, we speculate that some threonine dehydratases have evolved a novel function towards cysteine desulfuration, which benefits the producer to utilize cysteine as a sulfur source for better adapting external environments.

scholarly journals MPST but not CSE is the primary regulator of hydrogen sulfide production and function in the coronary artery

2016 ◽  
Vol 310 (1) ◽  
pp. H71-H79 ◽  
Author(s):  
Maggie M. Kuo ◽  
Dae Hee Kim ◽  
Sandeep Jandu ◽  
Yehudit Bergman ◽  
Siqi Tan ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Coronary Artery ◽  
Ex Vivo ◽  
Human Coronary Artery ◽  
Sodium Hydrosulfide ◽  
Physiological Relevance ◽  
Hydrogen Sulfide Production ◽  
And Function

Hydrogen sulfide (H2S) has emerged as an important gasotransmitter in the vasculature. In this study, we tested the hypothesis that H2S contributes to coronary vasoregulation and evaluated the physiological relevance of two sources of H2S, namely, cystathionine-γ-lyase (CSE) and 3-mercaptypyruvate sulfertransferase (MPST). MPST was detected in human coronary artery endothelial cells as well as rat and mouse coronary artery; CSE was not detected in the coronary vasculature. Rat coronary artery homogenates produced H2S through the MPST pathway but not the CSE pathway in vitro. In vivo coronary vasorelaxation response was similar in CSE knockout mice, wild-type mice (WT), and WT mice treated with the CSE inhibitor propargylglycine, suggesting that CSE-produced H2S does not have a significant role in coronary vasoregulation in vivo. Ex vivo, the MPST substrate 3-mercaptopyruvate (3-MP) and H2S donor sodium hydrosulfide (NaHS) elicited similar coronary vasoreactivity responses. Pyruvate did not have any effects on vasoreactivity. The vasoactive effect of H2S appeared to be nitric oxide (NO) dependent: H2S induced coronary vasoconstriction in the presence of NO and vasorelaxation in its absence. Maximal endothelial-dependent relaxation was intact after 3-MP and NaHS induced an increase in preconstriction tone, suggesting that endothelial NO synthase activity was not significantly inhibited. In vitro, H2S reacted with NO, which may, in part explain the vasoconstrictive effects of 3-MP and NaHS. Taken together, these data show that MPST rather than CSE generates H2S in coronary artery, mediating its effects through direct modulation of NO. This has important implications for H2S-based therapy in healthy and diseased coronary arteries.

scholarly journals Estimation of bacterial hydrogen sulfide production in vitro

2015 ◽  
Vol 7 (1) ◽  
pp. 28166 ◽  
Author(s):  
Amina Basic ◽  
Susanne Blomqvist ◽  
Anette Carlén ◽  
Gunnar Dahlén
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfide Production ◽  
Hydrogen Sulfide Production

Enhanced Sp1/YY1 Expression Directs CBS Transcription to Mediate VEGF-Stimulated Pregnancy-Dependent H 2 S Production in Human Uterine Artery Endothelial Cells

Hypertension ◽  
2021 ◽  
Author(s):  
Jin Bai ◽  
Dong-bao Chen
Keyword(s):  
Hydrogen Sulfide ◽  
Uterine Artery ◽  
Promoter Sequence ◽  
Vascular Endothelial ◽  
Promoter Activation ◽  
Sulfide Production ◽  
Hydrogen Sulfide Production ◽  
Specificity Protein ◽  
Endothelial Growth Factor

Pregnancy and VEGF (vascular endothelial growth factor) stimulate uterine artery endothelial cell (UAEC) hydrogen sulfide production via selectively upregulating CBS (cystathionine β-synthase) but not CSE (cystathionine γ-lyase) expression. This study was conducted to determine the mechanisms by which VEGF utilizes to stimulate pregnancy-dependent upregulation of CBS and hydrogen sulfide production in human UAEC. The proximal human CBS promoter contains 4 Sp1 (specificity protein 1; a/b/c/d) sites and 1 YY1 (Yin Yang 1) site; luciferase assays using reporter genes driven by human CBS promoter with a series of 5′-deletions identified a promoter sequence (−574 to −394) containing Sp1d and the YY1 sites critical for basal and VEGF-stimulated CBS promoter activation. VEGF stimulated pregnancy-dependent recruitment of Sp1 to Sp1d and YY1 to YY1 and also recruited YY1 to Sp1c and increased Sp1/YY1 association in pregnant human UAEC, suggesting formation of a Sp1/YY1 complex at the Sp1c site. Endothelial Sp1 and YY1 proteins were significantly greater in pregnant than nonpregnant human uterine artery. VEGF stimulated pregnancy-dependent Sp1 and YY1 protein expression in vitro. Treatment with Sp1 and YY1 siRNAs completely blocked Sp1/YY1-mediated pregnancy-dependent CBS protein upregulation and hydrogen sulfide production by VEGF in human UAEC. VEGF did not trans -activate CSE promoter or increase CSE expression, and Sp1/YY1 knockdown did not affect CSE expression in human UAEC. Thus, pregnancy augments EC Sp1 and YY1 expression and promotes the recruitment of Sp1/YY1 to their DNA-binding sequences in proximal human CBS promoter to upregulate CBS transcription, underlying a novel mechanism to mediate VEGF-stimulated pregnancy-dependent endothelial hydrogen sulfide production in the human uterine artery.

Endogenous hydrogen sulfide sulfhydrates IKKβ at cysteine 179 to control pulmonary artery endothelial cell inflammation

2019 ◽  
Vol 133 (20) ◽  
pp. 2045-2059 ◽  
Author(s):  
Da Zhang ◽  
Xiuli Wang ◽  
Siyao Chen ◽  
Selena Chen ◽  
Wen Yu ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Endothelial Cell ◽  
Pulmonary Artery ◽  
Cell Model ◽  
Site Directed Mutagenesis ◽  
Critical Event ◽  
Hypertensive Rats ◽  
Pulmonary Artery Endothelial Cell

Abstract Background: Pulmonary artery endothelial cell (PAEC) inflammation is a critical event in the development of pulmonary arterial hypertension (PAH). However, the pathogenesis of PAEC inflammation remains unclear. Methods: Purified recombinant human inhibitor of κB kinase subunit β (IKKβ) protein, human PAECs and monocrotaline-induced pulmonary hypertensive rats were employed in the study. Site-directed mutagenesis, gene knockdown or overexpression were conducted to manipulate the expression or activity of a target protein. Results: We showed that hydrogen sulfide (H2S) inhibited IKKβ activation in the cell model of human PAEC inflammation induced by monocrotaline pyrrole-stimulation or knockdown of cystathionine γ-lyase (CSE), an H2S generating enzyme. Mechanistically, H2S was proved to inhibit IKKβ activity directly via sulfhydrating IKKβ at cysteinyl residue 179 (C179) in purified recombinant IKKβ protein in vitro, whereas thiol reductant dithiothreitol (DTT) reversed H2S-induced IKKβ inactivation. Furthermore, to demonstrate the significance of IKKβ sulfhydration by H2S in the development of PAEC inflammation, we mutated C179 to serine (C179S) in IKKβ. In purified IKKβ protein, C179S mutation of IKKβ abolished H2S-induced IKKβ sulfhydration and the subsequent IKKβ inactivation. In human PAECs, C179S mutation of IKKβ blocked H2S-inhibited IKKβ activation and PAEC inflammatory response. In pulmonary hypertensive rats, C179S mutation of IKKβ abolished the inhibitory effect of H2S on IKKβ activation and pulmonary vascular inflammation and remodeling. Conclusion: Collectively, our in vivo and in vitro findings demonstrated, for the first time, that endogenous H2S directly inactivated IKKβ via sulfhydrating IKKβ at Cys179 to inhibit nuclear factor-κB (NF-κB) pathway activation and thereby control PAEC inflammation in PAH.

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