Biology:Coenzyme-B sulfoethylthiotransferase
| coenzyme-B sulfoethylthiotransferase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC number | 2.8.4.1 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
In enzymology, coenzyme-B sulfoethylthiotransferase, also known as methyl-coenzyme M reductase (MCR) or most systematically as 2-(methylthio)ethanesulfonate:N-(7-thioheptanoyl)-3-O-phosphothreonine S-(2-sulfoethyl)thiotransferase is an enzyme that catalyzes the final step in the formation of methane.[1] It does so by combining the hydrogen donor coenzyme B and the methyl donor coenzyme M. Via this enzyme, most of the natural gas on earth was produced. Ruminants (e.g. cows) produce methane because their rumens contain methanogenic prokaryotes (Archaea)[2][3] that encode and express the set of genes of this enzymatic complex.
The enzyme has two active sites, each occupied by the nickel-containing F430 cofactor.[4]
- + ⇌ CoM-S-S-CoB + methane
.svg)
.svg)
The two substrates of this enzyme are 2-(methylthio)ethanesulfonate and N-(7-mercaptoheptanoyl)threonine 3-O-phosphate; its two products are CoM-S-S-CoB and methane. 3-Nitrooxypropanol inhibits the enzyme.[5]
In some species, the enzyme reacts in reverse (a process called reverse methanogenesis), catalysing the anaerobic oxidation of methane, therefore removing it from the environment.[6] Such organisms are methanotrophs.
This enzyme belongs to the family of transferases, specifically those transferring alkylthio groups.
This enzyme participates in folate biosynthesis.[citation needed]
Structure
Coenzyme-B sulfoethylthiotransferase is a multiprotein complex made up of a pair of identical halves. Each half is made up of three subunits: α, β and γ,[7] also called McrA, McrB and McrG, respectively.
References
- ↑ Stephen W., Ragdale (2014). "Chapter 6. Biochemistry of Methyl-Coenzyme M Reductase: The Nickel Metalloenzyme that Catalyzes the Final Step in Synthesis and the First Step in Anaerobic Oxidation of the Greenhouse Gas Methane". in Peter M.H. Kroneck and Martha E. Sosa Torres. The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment. Metal Ions in Life Sciences. 14. Springer. pp. 125–145. doi:10.1007/978-94-017-9269-1_6.
- ↑ "Bovine Rumen - microbewiki". http://microbewiki.kenyon.edu/index.php/Bovine_Rumen#Methanogens.
- ↑ "Phylogenetic analysis of methanogens from the bovine rumen". BMC Microbiology 1: 5. 2001. doi:10.1186/1471-2180-1-5. PMID 11384509.
- ↑ "Biochemistry of methanogenesis: a tribute to Marjory Stephenson. 1998 Marjory Stephenson Prize Lecture". Microbiology 144 (9): 2377–406. September 1998. doi:10.1099/00221287-144-9-2377. PMID 9782487.
- ↑ "An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production". Proceedings of the National Academy of Sciences of the United States of America 112 (34): 10663–8. August 2015. doi:10.1073/pnas.1504124112. PMID 26229078. Bibcode: 2015PNAS..11210663H.
- ↑ "Reverse methanogenesis: testing the hypothesis with environmental genomics". Science 305 (5689): 1457–62. September 2004. doi:10.1126/science.1100025. PMID 15353801. Bibcode: 2004Sci...305.1457H.
- ↑ "Crystal structure of methyl-coenzyme M reductase: the key enzyme of biological methane formation". Science 278 (5342): 1457–62. November 1997. doi:10.1126/science.278.5342.1457. PMID 9367957. Bibcode: 1997Sci...278.1457E.
Further reading
- "Evidence that the heterodisulfide of coenzyme M and 7-mercaptoheptanoylthreonine phosphate is a product of the methylreductase reaction in Methanobacterium". Biochemical and Biophysical Research Communications 149 (2): 455–60. December 1987. doi:10.1016/0006-291X(87)90389-5. PMID 3122735.
- "Methyl-coenzyme-M reductase from Methanobacterium thermoautotrophicum (strain Marburg). Purity, activity and novel inhibitors". European Journal of Biochemistry 184 (1): 63–8. September 1989. doi:10.1111/j.1432-1033.1989.tb14990.x. PMID 2506016.
- "Methane formation by reaction of a methyl thioether with a photo-excited nickel thiolate--a process mimicking methanogenesis in archaea". Chemistry: A European Journal 6 (19): 3508–16. October 2000. doi:10.1002/1521-3765(20001002)6:19<3508::AID-CHEM3508>3.0.CO;2-W. PMID 11072815.
 |  |
