Methyltransferase MtaA/CmuA (IPR006360)

Short name: Mtase_MtaA_CmuA

Overlapping homologous superfamilies

Domain relationships


This entry represents a methyltransferase domain found in proteins which are involved in C1 metabolism in methanogenic archaea and methylotrophic bacteria. It is closely related to, yet is distinct from, uroporphyrinogen decarboxylase (EC:

In methanogens, this domain is found in single-domain proteins catalysing the transfer of the methyl group of methylcobalamin to coenzymeM [PMID: 8654414]. In Methanosarcina barkeri these proteins have been shown to be involved in methanogenesis from C1 compounds such as methylamine and dimethylsulphide [PMID: 8617801, PMID: 9371433].

CH3-cob(III)alamin + coenzymeM --> cob(I)alamin + CH3-coenzymeM

In methylotrophic bacteria, this domain is found at the N terminus of the bifunctional corrinoid-binding CmuA protein, which is involved in chloromethane utilisation. The pathway of chloromethane utilisation allows the microorganisms that possess it to grow with chloromethane as the sole carbon and energy source. It is initiated by a corrinoid-dependent methyltransferase system involving methyltransferase I (CmuA) and methyltransferase II (CmuB), which transfer the methyl group of chloromethane onto tetrahydrofolate [PMID: 10200311]. The methyl group of chloromethane is first transferred by the protein CmuA to its corrinoid moiety, from where it is transferred to tetrahydrofolate by CmuB, thereby yielding methyltetrahydrofolate [PMID: 10447694, PMID: 11358510].

CH3Cl + cob(I)alamin ---> CH3-cob(III)alamin + Cl-

GO terms

Biological Process

GO:0006730 one-carbon metabolic process

Molecular Function

GO:0008168 methyltransferase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.