Hydrogen sulfide (H2S) and nitric oxide (NO) are important signaling molecules that regulate several physiological functions. Understanding the chemistry behind their interplay is important for explaining these functions. The reaction of H2S with S-nitrosothiols to form the smallest S-nitrosothiol, thionitrous acid (HSNO), is one example of physiologically relevant cross-talk between H2S and nitrogen species. Perthionitrite (SSNO(-)) has recently been considered as an important biological source of NO that is far more stable and longer living than HSNO. In order to experimentally address this issue here, we prepared SSNO(-) by two different approaches, which lead to two distinct species: SSNO(-) and dithionitric acid [HON(S)S/HSN(O)S]. (H)S2NO species and their reactivity were studied by (15)N NMR, IR, electron paramagnetic resonance and high-resolution electrospray ionization time-of-flight mass spectrometry, as well as by X-ray structure analysis and cyclic voltammetry. The obtained results pointed toward the inherent instability of SSNO(-) in water solutions. SSNO(-) decomposed readily in the presence of light, water, or acid, with concomitant formation of elemental sulfur and HNO. Furthermore, SSNO(-) reacted with H2S to generate HSNO. Computational studies on (H)SSNO provided additional explanations for its instability. Thus, on the basis of our data, it seems to be less probable that SSNO(-) can serve as a signaling molecule and biological source of NO. SSNO(-) salts could, however, be used as fast generators of HNO in water solutions.
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http://dx.doi.org/10.1021/acs.inorgchem.5b00831 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Department of Chemistry and Biochemistry, Materials Science Institute, Knight Campus for Accelerating Scientific Impact, Institute of Molecular Biology, 1253 University of Oregon, Eugene, Oregon, 97403, United States.
Hydrogen sulfide (HS) and nitric oxide (NO) are important gaseous biological signaling molecules that are involved in complex cellular pathways. A number of physiological processes require both HS and NO, which has led to the proposal that different HS/NO⋅ crosstalk species, including thionitrite (SNO) and perthionitrite (SSNO), are responsible for this observed codependence. Despite the importance of these S/N hybrid species, the reported properties and characterization, as well as the fundamental pathways of formation and subsequent reactivity, remain poorly understood.
View Article and Find Full Text PDFInorg Chem
August 2024
School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India.
A comparative bioinspired reactivity study of new binuclear Zn(II) complexes featuring coordinated thiolate, selenolate, trisulfide and diselenide in relation with (i) the generation of reactive sulfur/selenium species (RSS/RSeS), (ii) the oxygen dependent oxidation and disproportionation of polysulfide (S) to produce sulfite (SO), thiosulfate (SO) and sulfide (S) by sulfur oxygenase reductase (SOR), and (iii) the reaction of S with nitrite (NO) to generate thionitrite (SNO), perthionitrite (SSNO) and nitric oxide (NO), is presented. The binuclear Zn(II)-thiolate/selenolate complexes could react with elemental sulfur to generate RSS/RSeS while similar reactions involving elemental selenium could not generate RSeS. The dizinc(II)-S and the dizinc(II)-Se complexes could react with dioxygen (O) to generate binuclear Zn(II) complexes featuring coordinated thiosulfate (SO) and selenite (SeO), respectively.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2023
School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-Tvm) Thiruvananthapuram, 695551, Kerala, India.
(Per)thionitrite (SNO /SSNO ) intermediates play vital roles in modulating nitric oxide (NO) and hydrogen sulfide (H S) dependent bio-signalling processes. Whilst the previous preparations of such intermediates involved reactive H S/HS or sulfane sulfur (S ) species, the present report reveals that relatively stable thiocarbonyl compounds (such as carbon disulfide (CS ), thiocarbamate, thioacetic acid, and thioacetate) react with nitrite anion to yield SNO /SSNO . For instance, the reaction of CS and nitrite anion (NO ) under ambient condition affords CO and SNO /SSNO .
View Article and Find Full Text PDFAngew Chem Int Ed Engl
July 2022
Department of Chemistry and Biochemistry, Materials Science Institute, Knight Campus for Accelerating Scientific Impact, and Institute of Molecular Biology, University of Oregon, Eugene, OR 97403-1253, USA.
S/N crosstalk species derived from the interconnected reactivity of H S and NO facilitate the transport of reactive sulfur and nitrogen species in signaling, transport, and regulatory processes. We report here that simple Fe ions, such as those that are bioavailable in the labile iron pool (LIP), react with thionitrite (SNO ) and perthionitrite (SSNO ) to yield the dinitrosyl iron complex [Fe(NO) (S )] . In the reaction of FeCl with SNO we were able to isolate the unstable intermediate hydrosulfido mononitrosyl iron complex [FeCl (NO)(SH)] , which was characterized by X-ray crystallography.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2021
Department of Chemistry, Georgetown University, Box 571227, Washington, DC, 20057-1227, USA.
NO and H S serve as signaling molecules in biology with intertwined reactivity. HSNO and HSSNO with their conjugate bases SNO and SSNO form in the reaction of H S with NO as well as S-nitrosothiols (RSNO) and nitrite (NO ) that serve as NO reservoirs. While HSNO and HSSNO are elusive, their conjugate bases form isolable zinc complexes TpZn(SNO) and TpZn(SSNO) supported by tris(pyrazolyl)borate ligands.
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