Reaction: a [methyl-Co(III) methanol-specific corrinoid protein] + CoM = methyl-CoM + a [Co(I) methanol-specific corrinoid protein]
Glossary: CoM = coenzyme M = 2-sulfanylethane-1-sulfonate = 2-mercaptoethanesulfonate (deprecated)
Other name(s): methyltransferase 2 (ambiguous); mtaA (gene name)
Systematic name: methylated methanol-specific corrinoid protein:Coenzyme M methyltransferase
Comments: The enzyme, which is involved in methanogenesis from methanol, catalyses the transfer of a methyl group from a corrinoid protein (see EC 2.1.1.90, methanol—corrinoid protein Co-methyltransferase), where it is bound to the cobalt cofactor, to coenzyme M, forming the substrate for EC 2.8.4.1, coenzyme-B sulfoethylthiotransferase, the enzyme that catalyses the final step in methanogenesis. Free methylcob(I)alamin can substitute for the corrinoid protein in vitro [5].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. LeClerc, G.M. and Grahame, D.A. Methylcobamide:coenzyme M methyltransferase isozymes from Methanosarcina barkeri. Physicochemical characterization, cloning, sequence analysis, and heterologous gene expression. J. Biol. Chem. 271 (1996) 18725-18731. [PMID: 8702528]
2. Harms, U. and Thauer, R.K. Methylcobalamin: coenzyme M methyltransferase isoenzymes MtaA and MtbA from Methanosarcina barkeri. Cloning, sequencing and differential transcription of the encoding genes, and functional overexpression of the mtaA gene in Escherichia coli. Eur. J. Biochem. 235 (1996) 653-659. [PMID: 8654414]
3. Sauer, K. and Thauer, R.K. Methanol:coenzyme M methyltransferase from Methanosarcina barkeri. Zinc dependence and thermodynamics of the methanol:cob(I)alamin methyltransferase reaction. Eur. J. Biochem. 249 (1997) 280-285. [PMID: 9363780]
4. Sauer, K., Harms, U. and Thauer, R.K. Methanol:coenzyme M methyltransferase from Methanosarcina barkeri. Purification, properties and encoding genes of the corrinoid protein MT1. Eur. J. Biochem. 243 (1997) 670-677. [PMID: 9057830]
5. Sauer, K. and Thauer, R.K. Methanol:coenzyme M methyltransferase from Methanosarcina barkeri – substitution of the corrinoid harbouring subunit MtaC by free cob(I)alamin. Eur. J. Biochem. 261 (1999) 674-681. [PMID: 10215883]