MET17/YLR303W Summary Help

Standard Name MET17 1
Systematic Name YLR303W
Alias MET15 , MET25
Feature Type ORF, Verified
Description O-acetyl homoserine-O-acetyl serine sulfhydrylase; required for Methionine and cysteine biosynthesis (2, 3 and see Summary Paragraph)
Name Description METhionine requiring 1
Chromosomal Location
ChrXII:732542 to 733876 | ORF Map | GBrowse
Gene Ontology Annotations All MET17 GO evidence and references
  View Computational GO annotations for MET17
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Regulators 15 genes
Classical genetics
Large-scale survey
29 total interaction(s) for 26 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 10
  • Affinity Capture-Western: 1
  • Biochemical Activity: 5
  • Co-purification: 1

Genetic Interactions
  • Dosage Rescue: 2
  • Negative Genetic: 3
  • Phenotypic Enhancement: 1
  • Synthetic Growth Defect: 4
  • Synthetic Lethality: 2

Expression Summary
Length (a.a.) 444
Molecular Weight (Da) 48,671
Isoelectric Point (pI) 6.42
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXII:732542 to 733876 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1335 732542..733876 2011-02-03 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000004294

MET17 encodes a bifunctional enzyme with O-acetylserine and O-acetylhomoserine sulfhydrylase activities (4, 5, 6). Met17p functions in cells to catalyze the incorporation of sulfide into O-acetylhomoserine to form homocysteine, which is then used in the biosynthesis of the sulfur-containing amino acids cysteine and methionine (7). Met17p forms a homotetrameric enzyme of four subunits (8) and binding to pyridoxal phosphate enhances the stability of the protein (9). Transcription of MET17 is mainly regulated by the transcription factors of the sulfur metabolic network; it is positively regulated by Met4p and Cbf1p and negatively regulated by Met31p and Met32p (10, 11, 12, 13). MET17 expression can also be regulated by Gcn4p, Cbf1p, and Sir4p (14, 15, 16, 17).

Strains null for met17 require organic sulfur sources for growth and are thus auxotrophs for methionine, cysteine, homocysteine, and AdoMet (7, 1, 18, 19); they are also resistant to methyl mercury and cadmium (19, 20). In the presence of Pb2+, met17 null colonies become darkly pigmented (21). Met17p homologs can be found in numerous organisms including bacteria, archaea, fungi, and plants (22, 23, 24, 25). O-acetylhomoserine sulfhydrylases, bacterial cystathionine gamma-lyases and cystathionine beta-lyases, as well as eukaryotic cystathionine gamma-lyase all share some sequence similarity and are thought to have descended from an ancestral pyridoxal phosphate enzyme (reviewed in 7).

Last updated: 2011-02-07 Contact SGD

References cited on this page View Complete Literature Guide for MET17
1) Masselot M and De Robichon-Szulmajster H  (1975) Methionine biosynthesis in Saccharomyces cerevisiae. I. Genetical analysis of auxotrophic mutants. Mol Gen Genet 139(2):121-32
2) Yamagata S, et al.  (1994) Overexpression of the Saccharomyces cerevisiae MET17/MET25 gene in Escherichia coli and comparative characterization of the product with O-acetylserine.O-acetylhomoserine sulfhydrylase of the yeast. Appl Microbiol Biotechnol 42(1):92-9
3) Brzywczy J and Paszewski A  (1993) Role of O-acetylhomoserine sulfhydrylase in sulfur amino acid synthesis in various yeasts. Yeast 9(12):1335-42
4) Yamagata S  (1981) Low-molecular-weight O-acetylserine sulfhydrylase and serine sulfhydrylase of Saccharomyces cerevisiae are the same protein. J Bacteriol 147(2):688-90
5) D'Andrea R, et al.  (1987) Molecular genetics of met 17 and met 25 mutants of Saccharomyces cerevisiae: intragenic complementation between mutations of a single structural gene. Mol Gen Genet 207(1):165-70
6) Kerjan P, et al.  (1986) Nucleotide sequence of the Saccharomyces cerevisiae MET25 gene. Nucleic Acids Res 14(20):7861-71
7) Thomas D and Surdin-Kerjan Y  (1997) Metabolism of sulfur amino acids in Saccharomyces cerevisiae. Microbiol Mol Biol Rev 61(4):503-32
8) Yamagata S  (1976) O-Acetylserine and O-acetylhomoserine sulfhydrylase of yeast. Subunit structure. J Biochem (Tokyo) 80(4):787-97
9) Yamagata S and Takeshima K  (1976) O-Acetylserine and O-acetylhomoserine sulfhydrylase of yeast. Further purification and characterization as a pyridoxal enzyme. J Biochem (Tokyo) 80(4):777-85
10) Thomas D, et al.  (1992) MET4, a leucine zipper protein, and centromere-binding factor 1 are both required for transcriptional activation of sulfur metabolism in Saccharomyces cerevisiae. Mol Cell Biol 12(4):1719-27
11) Thomas D, et al.  (1990) Gene-enzyme relationship in the sulfate assimilation pathway of Saccharomyces cerevisiae. Study of the 3'-phosphoadenylylsulfate reductase structural gene. J Biol Chem 265(26):15518-24
12) Kuras L, et al.  (1997) Assembly of a bZIP-bHLH transcription activation complex: formation of the yeast Cbf1-Met4-Met28 complex is regulated through Met28 stimulation of Cbf1 DNA binding. EMBO J 16(9):2441-51
13) Blaiseau PL, et al.  (1997) Met31p and Met32p, two related zinc finger proteins, are involved in transcriptional regulation of yeast sulfur amino acid metabolism. Mol Cell Biol 17(7):3640-8
14) O'Connell KF, et al.  (1995) Role of the Saccharomyces cerevisiae general regulatory factor CP1 in methionine biosynthetic gene transcription. Mol Cell Biol 15(4):1879-88
15) Kent NA, et al.  (1994) Chromatin structure modulation in Saccharomyces cerevisiae by centromere and promoter factor 1. Mol Cell Biol 14(8):5229-41
16) Mellor J, et al.  (1991) DNA binding of CPF1 is required for optimal centromere function but not for maintaining methionine prototrophy in yeast. Nucleic Acids Res 19(11):2961-9
17) Smith JS and Boeke JD  (1997) An unusual form of transcriptional silencing in yeast ribosomal DNA. Genes Dev 11(2):241-54
18) Yamagata S, et al.  (1975) O-acetylserine and O-acetylhomoserine sulfhydrylase of yeast; studies with methionine auxotrophs. J Biochem (Tokyo) 77(5):1029-36
19) Singh A and Sherman F  (1974) Characteristics and relationships of mercury-resistant mutants and methionine auxotrophs of yeast. J Bacteriol 118(3):911-8
20) Hwang GW, et al.  (2007) Ubiquitin-conjugating enzyme Cdc34 mediates cadmium resistance in budding yeast through ubiquitination of the transcription factor Met4. Biochem Biophys Res Commun 363(3):873-8
21) Cost GJ and Boeke JD  (1996) A useful colony colour phenotype associated with the yeast selectable/counter-selectable marker MET15. Yeast 12(10):939-41
22) Auger S, et al.  (2002) The metIC operon involved in methionine biosynthesis in Bacillus subtilis is controlled by transcription antitermination. Microbiology 148(Pt 2):507-18
23) Borup B and Ferry JG  (2000) O-Acetylserine sulfhydrylase from Methanosarcina thermophila. J Bacteriol 182(1):45-50
24) Morzycka E and Paszewski A  (1982) Cysteine and homocysteine synthesis in Saccharomycopsis lipolytica; identification and characterization of two cysteine synthases. Acta Biochim Pol 29(1-2):81-93
25) Barroso C, et al.  (1999) Salt-specific regulation of the cytosolic O-acetylserine(thiol)lyase gene from Arabidopsis thaliana is dependent on abscisic acid. Plant Mol Biol 40(4):729-36