This enzyme catalyzes the 6-electron reduction of sulfite to sulfide. This is one of several activities required for the biosynthesis of L-cysteine from sulfate. 3 H2O + hydrogen sulfide + 3 NADP+ = 4 H+ + 3 NADPH + sulfite.
MPVEFATNPFGEAKNATSLPKYGTPVTAISSVLFNNVDSIFAYKSFSQPDLLHQDLKKWS
EKRGNESRGKPFFQELDIRSGAGLAPLGFSHGLKNTTAIVAPGFSLPYFINSLKTVSHDG
KFLLNVGALNYDNATGSVTNDYVTALDAASKLKYGVVTPISANEVQSVALLALAIATFSN
NSGAINLFDGLNYSKTVLPLVESVPEASILAKLSKVIAPDAAFDDVLDKFNELTGLRLHN
FQYFGAQDAETVFITYGSLESELFNSAISGNNSKIGLINVRVPLPFNVAKFVTHVPSTTK
QIVVIGQTLDGSSPSFLRSQVSAALFYHGRTSISVSEYIYQPDFIWSPKAVKSIVSSFIP
EFTYNADSSFGEGFIYWASDKSINIDVASKLVKALSLEDGKFVSLRTKFDNLANAGTFQA
QFVTSKEQIPVSNIDSTKLSVVEDVSLLKHLDVAATVAEQGSIALVSQKAVKDLDLNSVE
SYVKNLGIPESFLISIAKKNIKLFIIDGETTNDESKLSLFIQAVFWKLAFGLDVAECTNR
IWKSIDSGADISAASISEFLTGAFKNFLSEVPLALYTKFSEINIEKKEDEEEPAALPIFV
NETSFLPNNSTIEEIPLPETSEISDIAKKLSFKEAYEVENKLRPDLPVKNFVVKVKENRR
VTPADYDRYIFHIEFDISGTGMTYDIGEALGIHARNNESLVKEFLTFYGLNESDVVLVPN
KDNHHLLETRTVLQAFVENLDIFGKPPKRFYESLIPYASNEEEKKKLEDLVTPAGAVDLK
RFQDVEYYTYADIFELFPSVRPSLEELVTIIEPLKRREYSIASSQKVHPNEVHLLIVVVD
WVDNKGRKRYGQASKYISDLAVGSELVVSVKPSVMKLPPSPKQPVIMSGLGTGLAPFKAI
VEEKLWQKQQGYEIGEVFLYLGSRHKREEYLYGELWEAYKDAGIITHIGAAFSRDQPQKI
YIQDRIKENLDELKTAMIDNKGSFYLCGPTWPVPDITQALQDILAKDAEERGIKVDLDAA
IEELKEASRYILEVY1052
| PMID | Title & Author | Abstract | Year | |
| 0 | 7928966 | Two divergent MET10 genes, one from Saccharomyces cerevisiae and one from Saccharomyces carlsbergensis, encode the alpha subunit of sulfite reductase and specify potential binding sites for FAD and NADPH.J Hansen , H Cherest, M C Kielland-Brandt | The yeast assimilatory sulfate reductase is a complex enzyme that is responsible for conversion of sulfite into sulfide. To obtain information on the nature of this enzyme, we isolated and sequenced the MET10 gene of Saccharomyces cerevisiae and a divergent MET10 allele from Saccharomyces carlsbergensis. The polypeptides deduced from the identically sized open reading frames (1,035 amino acids) of both MET10 genes have molecular masses of around 115 kDa and are 88% identical to each other. The transcript of S. cerevisiae MET10 has a size comparable to that of the open reading frame and is transcriptionally repressed by methionine in a way similar to that seen for other MET genes of S. cerevisiae. Distinct homology was found between the putative MET10-encoded polypeptide and flavin-interacting parts of the sulfite reductase flavoprotein subunit (encoded by cysJ) from Escherichia coli and several other flavoproteins. A significant N-terminal homology to pyruvate flavodoxin oxidoreductase (encoded by nifJ) from Klebsiella pneumoniae, together with a lack of obvious flavin mononucleotide-binding motifs in the MET10 deduced amino acid sequence, suggests that the yeast assimilatory sulfite reductase is a distinct type of sulfite reductase. | 1994 |
| 1 | 20889780 | Identification of MET10-932 and characterization as an allele reducing hydrogen sulfide formation in wine strains of Saccharomyces cerevisiae.Angela Linderholm , Kevin Dietzel, Marissa Hirst, Linda F Bisson | A vineyard isolate of the yeast Saccharomyces cerevisiae, UCD932, was identified as a strain producing little or no detectable hydrogen sulfide during wine fermentation. Genetic analysis revealed that this trait segregated as a single genetic determinant. The gene also conferred a white colony phenotype on BiGGY agar (bismuth-glucose-glycine-yeast agar), which is thought to indicate low basal levels of sulfite reductase activity. However, this isolate does not display a requirement for S-containing amino acids, indicating that the sulfate reduction pathway is fully operational. Genetic crosses against known mutations conferring white colony color on BiGGY agar identified the gene leading to reduced H(2)S formation as an allele of MET10 (MET10-932), which encodes a catalytic subunit of sulfite reductase. Sequence analysis of MET10-932 revealed several corresponding amino acid differences in relation to laboratory strain S288C. Allele differences for other genes of the sulfate reduction pathway were also detected in UCD932. The MET10 allele of UCD932 was found to be unique in comparison to the sequences of several other vineyard isolates with differing levels of production of H(2)S. Replacing the MET10 allele of high-H(2)S-producing strains with MET10-932 prevented H(2)S formation by those strains. A single mutative change, corresponding to T662K, in MET10-932 resulted in a loss of H(2)S production. The role of site 662 in sulfide reduction was further analyzed by changing the encoded amino acid at this position. A change back to threonine or to the conservative serine fully restored the H(2)S formation conferred by this allele. In addition to T662K, arginine, tryptophan, and glutamic acid substitutions similarly reduced sulfide formation. | 2010 |
| 2 | 9634827 | Inactivation of MET10 in brewer's yeast specifically increases SO2 formation during beer production.J Hansen, M C Kielland-Brandt | Sulfite is widely used as an antioxidant in food production. In beer brewing, sulfite has the additional role of stabilizing the flavor by forming adducts with aldehydes. Inadequate amounts of sulfite are sometimes produced by brewer's yeasts, so means of controlling the sulfite production are desired. In Saccharomyces yeasts, MET10 encodes a subunit of sulfite reductase. Partial or full elimination of MET10 gene activity in a brewer's yeast resulted in increased sulfite accumulation. Beer produced with such yeasts was quite satisfactory and showed increased flavor stability. | 1996 |
| 3 | 8787893 | Antifungal azoxybacilin exhibits activity by inhibiting gene expression of sulfite reductase.Y Aoki , M Yamamoto, S M Hosseini-Mazinani, N Koshikawa, K Sugimoto, M Arisawa | Azoxybacilin, produced by Bacillus cereus, has a broad spectrum of antifungal activity in methionine-free medium and has been suggested to inhibit sulfite fixation. We have further investigated the mode of action by which azoxybacilin kills fungi. The compound inhibited the incorporation of [35S] sulfate into acid-insoluble fractions of Saccharomyces cerevisiae under conditions in which virtually no inhibition was observed for DNA, RNA, or protein synthesis. It did not interfere with the activity of the enzymes for sulfate assimilation but clearly inhibited the induction of those enzymes when S. cerevisiae cells were transferred from rich medium to a synthetic methionine-free medium. Particularly strong inhibition was observed in the induction of sulfite reductase. Northern (RNA) analysis revealed that azoxybacilin decreased the level of mRNA of genes for sulfate assimilation, including MET10 for sulfite reductase and MET4, the transactivator of MET10 and other sulfate assimilation genes. When activities of azoxybacilin were compared for mRNA and enzyme syntheses from MET10, the concentration required for inhibition of transcription of the gene was about 10 times higher (50% inhibitory concentration = 30 micrograms/ml) than that required for inhibition of induction of enzyme synthesis (50% inhibitory concentration = 3 micrograms/ml). The data suggest that azoxybacilin acts on at least two steps in the expression of sulfite reductase; the transcriptional activation of MET4 and a posttranscriptional regulation in MET10 expression. We conclude that azoxybacilin exhibits antifungal activity by interfering with the regulation of expression of sulfite reductase activity. | 1996 |
Hansen J, Cherest H, Kielland-Brandt M C. Two divergent MET10 genes, one from Saccharomyces cerevisiae and one from Saccharomyces carlsbergensis, encode the alpha subunit of sulfite reductase and specify potential binding sites for FAD and NADPH[J]. Journal of bacteriology, 1994, 176(19): 6050-6058.