Sulfur transferases

Sulfur transferases
Enzyme classification
EC, category	2.8.1.- ,  transferase
Response type	Transfer of sulphurous groups

Sulfur transferases are enzymes that transfer sulfur-containing groups from a sulfur donor to a nucleophilic sulfur acceptor. Due to their catalytic reaction, they form a common class of enzymes . Sulfur transferases are widespread in archaea , eubacteria and eukaryotes . In plants, they occur in different compartments of the cell, in the cytoplasm , in mitochondria , in the plastids and possibly in the peroxisomes .

construction

Sulfur transferases are encoded by the same family of genes in most organisms. The distinguishing feature is the rhodanase domain , which consists of a tandem repetition. The C-terminal domain contains the L- cysteine ​​residue of the active site . There are sulfur transferases with one and those with two rhodanase domains as well as sulfur transferases with an inactive rhodanase domain. Two-domain sulfurtransferases consist of two globular domains that are linked by a short amino acid chain (linker).

reaction

The best characterized is bovine rhodanase from the liver. The substrates of bovine rhodanase are thiosulfate and cyanide . The products are thiocyanate and sulfite . The sulfur is transferred from thiosulfate to cyanide in vitro. Cyanide is oxidized to thiocyanate and thiosulfate to sulfite.

${\displaystyle \mathrm {S_{2}O_{3}^{2-}+CN^{-}\longrightarrow SCN^{-}+SO_{3}^{2-}} }$

The reaction takes place in two steps. In the first step, a persulfide is formed by transferring the sulfur atom from the sulfur donor thiosulfate in the catalytic center of the bovine rhodanese at the L - cysteine ​​residue Cys-247 of the active center. The persulfide is dissolved in the second step, whereby the sulfur atom is transferred to the cyanide.

${\displaystyle \mathrm {{\text{Rhodanese}}+S_{2}O_{3}^{2-}\longrightarrow {\text{Rhodanese-S}}+SO_{3}^{2-}} }$

${\displaystyle \mathrm {{\text{Rhodanese-S}}+CN^{-}\longrightarrow {\text{Rhodanese}}+SCN^{-}} }$

The transfer of the sulfur atom is catalyzed by the L - cysteine ​​residue Cys-243; L - arginine -186 and L - lysine -249 seem to be involved in substrate binding .

function

The exact function of the sulfur transferases is not known, but several possible functions are described: Detoxification of cyanide, which produces the largely non-toxic thiocyanate. Detoxification of free oxygen radicals by thioredoxin reductase . Further functions are the participation in the assimilation of sulfate, as well as the provision of reduced sulfur for biosynthesis z. B. for iron-sulfur clusters . Contributing to the mobilization and transport of reduced sulfur during senescence in newly grown plant organs is also suggested. A role in defense against pathogens is also seen as a possible function.

Enzyme classification

The sulfur transferases ( EC  2.8.1.- ) form eight subgroups:

• Thiosulfate sulfur transferase ( EC  2.8.1.1 )
• 3-mercaptopyruvate sulfur transferase ( EC  2.8.1.2 )
• Thiosulphate thiol sulfur transferase ( EC  2.8.1.3 )
• tRNA sulfur transferase ( EC  2.8.1.4 )
• Thiosulfate dithiol sulfur transferase ( EC  2.8.1.5 )
• Biotin synthase ( EC  2.8.1.6 )
• Cysteine ​​desulfurase ( EC  2.8.1.7 )
• Lipoyl synthase ( EC  2.8.1.8 )

Individual evidence

1. ↑ Bauer M, Dietrich C, Nowak K, Sierralta WD, Papenbrock J: Intracellular localization of Arabidopsis sulfurtransferases . In: Plant Physiol. . 135, No. 2, June 2004, pp. 916-26. doi : 10.1104 / pp.104.040121 . PMID 15181206 . PMC 514126 (free full text).
2. ^ Bordo D, Bork P: The rhodanese / Cdc25 phosphatase superfamily. Sequence-structure-function relations . In: EMBO Rep. . 3, No. 8, August 2002, pp. 741-6. doi : 10.1093 / embo-reports / kvf150 . PMID 12151332 . PMC 1084204 (free full text).
3. ↑ ^{a b} Ploegman JH, Drent G, Kalk KH, et al. : The covalent and tertiary structure of bovine liver rhodanese . In: Nature . 273, No. 5658, May 1978, pp. 124-9. PMID 643076 .
4. ↑ Westley J: rhodanese . In: Adv. Enzymol. Relat. Areas Mol. Biol. , 39, 1973, pp. 327-68. PMID 4583640 .
5. ↑ Gliubich F, Gazerro M, G Zanotti, Delbono S, G Bombieri, Berni R: Active site structural features for Chemically modified forms of rhodanese . In: J. Biol. Chem. . 271, No. 35, August 1996, pp. 21054-61. PMID 8702871 .
6. ↑ Vennesland B , Castric PA, Conn EE, Solomonson LP, Volini M, Westley J: Cyanide metabolism . In: Fed. Proc. . 41, No. 10, August 1982, pp. 2639-48. PMID 7106306 .
7. ^ Nandi DL, Horowitz PM, Westley J: Rhodanese as a thioredoxin oxidase . In: Int. J. Biochem. Cell Biol . 32, No. 4, April 2000, pp. 465-73. PMID 10762072 .
8. ↑ Donadio S, Shafiee A, Hutchinson CR: Disruption of a rhodaneselike gene results in cysteine ​​auxotrophy in Saccharopolyspora erythraea . In: J. Bacteriol. . 172, No. 1, January 1990, pp. 350-60. PMID 2294090 . PMC 208439 (free full text).
9. ↑ Bonomi F, Pagani S, Cerletti P, Cannella C: Rhodanese-Mediated sulfur transfer to succinate dehydrogenase . In: Eur. J. Biochem. . 72, No. 1, January 1977, pp. 17-24. PMID 318999 .
10. ↑ Papenbrock J, Schmidt A: Characterization of two sulfurtransferase isozymes from Arabidopsis thaliana . In: Eur. J. Biochem. . 267, No. 17, September 2000, pp. 5571-9. PMID 10951216 .
11. ↑ Meyer T, Burow M, Bauer M, Papenbrock J: Arabidopsis sulfurtransferases: investigation of their function during senescence and in cyanide detoxification . In: Planta . 217, No. 1, May 2003, pp. 1-10. doi : 10.1007 / s00425-002-0964-5 . PMID 12721843 .
12. ↑ Bartels A, Mock HP, Papenbrock J: Differential expression of Arabidopsis sulfurtransferases under various growth conditions . In: Plant Physiol. Biochem. . 45, No. 3-4, 2007, pp. 178-87. doi : 10.1016 / j.plaphy.2007.02.005 . PMID 17408957 .
13. ↑ Caplan JL, Mamillapalli P, Burch-Smith TM, Czymmek K, Dinesh-Kumar SP: Chloroplastic protein NRIP1 mediates innate immune receptor recognition of a viral effector . In: Cell . 132, No. 3, February 2008, pp. 449-62. doi : 10.1016 / j.cell.2007.12.031 . PMID 18267075 . PMC 2267721 (free full text).