MET8/YBR213W Summary Help

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
Chromosomal Location
ChrII:650368 to 651192 | ORF Map | GBrowse
Genetic position: 119 cM
Gene Ontology Annotations All MET8 GO evidence and references
  View Computational GO annotations for MET8
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 4 genes
Classical genetics
Large-scale survey
17 total interaction(s) for 17 unique genes/features.
Physical Interactions
  • Affinity Capture-RNA: 1
  • PCA: 1
  • Reconstituted Complex: 1

Genetic Interactions
  • Dosage Growth Defect: 1
  • Negative Genetic: 8
  • Positive Genetic: 5

Expression Summary
Length (a.a.) 274
Molecular Weight (Da) 31,917
Isoelectric Point (pI) 6.26
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrII:650368 to 651192 | ORF Map | GBrowse
Genetic position: 119 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1997-01-28
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..825 650368..651192 2011-02-03 1997-01-28
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 SGDIDS000000417

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. Assimilatory nitrite reductases are also found in bacteria, plants, and fungi, but not in the yeast Saccharomyces cerevisiae. Thus, in S. cerevisiae siroheme is used exclusively in sulfite reductase (6).

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, 6, 5).

Last updated: 2007-10-03 Contact SGD

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) 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
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