MET8/YBR213W Summary Help

MET8 BASIC INFORMATION

Standard Name MET8 1, 2
Systematic Name YBR213W
Feature Type ORF, Verified
Description Bifunctional dehydrogenase and ferrochelatase, involved in the biosynthesis of siroheme, a prosthetic group used by sulfite reductase; required for sulfate assimilation and methionine biosynthesis (3, 4, 5 and see Summary Paragraph)
Name Description METhionine requiring 1
GO Annotations All MET8 GO evidence and references
    View Computational GO annotations for MET8
Molecular Function
Manually curated
Biological Process
Manually curated
High-throughput
Cellular Component
Manually curated
Pathways
Mutant Phenotype All MET8 Phenotype details and references
Classical genetics
null
Large-scale survey
null
Interactions MET8 All interactions details and references
2 total interaction(s) for 2 unique genes/features.
Physical Interactions
  • PCA: 1
  • Reconstituted Complex: 1
Sequence Information
ChrII:650363 to 651187 | ORF Map | GBrowse
Gbrowse
Genetic position: 119 cM
Last Update Coordinates: 2004-07-16 | Sequence: 1997-01-28
Subfeature details
Relative
Coordinates		 Chromosomal
Coordinates		 Most Recent Updates
Coordinates Sequence
CDS 1..825 650363..651187 2004-07-16 1997-01-28
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | UniProtKB
Primary SGDIDS000000417

MET8 RESOURCES

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Expression Summary histogram

ADDITIONAL INFORMATION for MET8

SUMMARY PARAGRAPH for MET8

About siroheme biosynthesis

Sulfite and nitrite reductases catalyze the six-electron reduction of sulphite to sulfide and nitrite to ammonia, respectively, which are key enzymatic steps in the assimilation of sulfur and nitrogen into all life forms (6). Siroheme, a modified cyclic tetrapyrrole, similar in structure to heme, chlorophyll and cobalamin, is used as a prosthetic group by sulfite and nitrite reductases (7). Similar to many cyclic tetrapyrroles, siroheme coordinates with a metal in its central cavity. While siroheme and heme coordinate an iron atom, chlorophyll and cobalamin coordinate maganesium and cobalt, respectively.

Assimilatory sulfite reductases are found in bacteria, plants and fungi, but not in animals, while dissimilatory sulfite reductases are found in diverse sulfate-reducing eubacteria and some species of thermophilic archaebacteria (6). Assimilatory nitrite reductases are also found in bacteria, plants, and fungi (6), but not in the yeast Saccharomyces cerevisiae. Thus, in S. cerevisiae siroheme is used exclusively in sulfite reductase.

The biologically important modified tetrapyrroles, such as siroheme, heme, chlorophyll and cobalamin share a common biosynthetic pathway up to the synthesis of the first macrocyclic intermediate uroporphyrinogen-III (8). Siroheme is biosynthesized from uroporphyringoen-III in four enzymatic steps: two transmethylations, a dehydrogenation, and a ferrochelation (3). In S. cerevisiae the two transmethylations are catalyzed by Met1p, a uroporphyrin III methyltransferase that requires S-adenosyl-L-methionine (AdoMet) as a methyl donor, and the dehydrogenation and ferrochelation reactions are catalyzed by the bifunctional enzyme Met8p (3, 9, 5).

Last updated: 2007-10-03

REFERENCES CITED ON THIS PAGE [View Complete Literature Guide for MET8]

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) Nelbock, P., et al.  (1989) ; Personal Communication, Mortimer Map Edition 10
3) Raux E, et al.  (1999) The role of Saccharomyces cerevisiae Met1p and Met8p in sirohaem and cobalamin biosynthesis. Biochem J 338 ( Pt 3)():701-8
4) Thomas D, et al.  (1992) Physiological analysis of mutants of Saccharomyces cerevisiae impaired in sulphate assimilation. J Gen Microbiol 138(10):2021-8
5) Schubert HL, et al.  (2002) The structure of Saccharomyces cerevisiae Met8p, a bifunctional dehydrogenase and ferrochelatase. EMBO J 21(9):2068-75
6) Crane BR and Getzoff ED  (1996) The relationship between structure and function for the sulfite reductases. Curr Opin Struct Biol 6(6):744-56
7) Murphy MJ and Siegel LM  (1973) Siroheme and sirohydrochlorin. The basis for a new type of porphyrin-related prosthetic group common to both assimilatory and dissimilatory sulfite reductases. J Biol Chem 248(19):6911-9
8) Warren MJ and Scott AI  (1990) Tetrapyrrole assembly and modification into the ligands of biologically functional cofactors. Trends Biochem Sci 15(12):486-91
9) Hansen J, et al.  (1997) Siroheme biosynthesis in Saccharomyces cerevisiae requires the products of both the MET1 and MET8 genes. FEBS Lett 401(1):20-4