2.1.1.247: [methyl-Co(III) methylamine-specific corrinoid protein]:coenzyme M methyltransferase
This is an abbreviated version! For detailed information about [methyl-Co(III) methylamine-specific corrinoid protein]:coenzyme M methyltransferase, go to the full flat file.
Reaction
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Synonyms
corrinoid:coenzyme M methyltransferase, methylated MtmC protein:CoM methyltransferase, methylated [methylamine-specific corrinoid protein]:coenzymeM methyltransferase, methylcobamide:coenzyme M methyltransferase, methylcobamide:CoM methyltransferase, methylcorrinoid:Coenzyme M methyltransferase, methylcorrinoid:CoM methyltransferase, methyltransferase 2, methyltransferase II, MMA-specific methyltransferase, MMA:CoM methyl transferase, MM_1070, MT2, MT2-A, MT2-M, mtaA, mtbA, TMA-specific methyltransferase, TMA:CoM methyl transferase, TMA:CoM methyltransferase, trimethylamine:coenzyme M methyltransferase
reconstitution of apo-enzyme with Co2+ yields an enzyme with 16fold higher specific activity, cysteine thiolate coordination in approximate tetrahedral geometry indicated by strong d-d transition absorbance centered at 622 nm, overview
required for activity by both isozymes MT2-A and MT2-M, tightly bound by the enzyme, 0.63 mol of Zn/mol of MT2-A, can be substituted by Co2+, which results in 16fold higher activity. Zn2+-MT2-A reveals 2S + 2N/O coordination with evidence for involvement of histidine. Interaction with the substrate CoM (2-mercaptoethanesulfonic acid) results in replacement of the second N/O group with S, indicating direct coordination of the CoM thiolate. Additional formation of an additional metal-thiolate bond, overview. Model formation in which metalthiolate formation occurs separately from H+ release from the enzyme-substrate complex at pH 6.2-7.7
the Zn2+ ion in the active site of MtaA is coordinated tetrahedrally via His240, Cys242 and Cys319. In the substrate-free form the fourth ligand is Glu263