Information on EC 2.1.1.251 - methylated-thiol-coenzyme M methyltransferase

CoM methylase

DMS:CoM methyltransferase

methylthiol:coenzyme M methyltransferase

methylthiol:CoM methyltransferase

methyltransferase II

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MMPA:CoM methyltransferase

MtsA

a [methyl-Co(III) methylated-thiol-specific corrinoid protein] + CoM = methyl-CoM + a [Co(I) methylated-thiol-specific corrinoid protein]

methanethiol + a [Co(I) methylated-thiol-specific corrinoid protein] = a [methyl-Co(III) methylated-thiol-specific corrinoid protein] + hydrogen sulfide

1a

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methanethiol + CoM = methyl-CoM + hydrogen sulfide

overall reaction

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KEGG

Sulfur metabolism

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, ,

methylated-thiol:coenzyme M methyltransferase

The enzyme, which is involved in methanogenesis from methylated thiols, such as methane thiol, dimethyl sulfide, and 3-(methylsulfanyl)propanoate, catalyses two successive steps - the transfer of a methyl group from the substrate to the cobalt cofactor of a methylated-thiol-specific corrinoid protein (MtsB), and the subsequent transfer of the methyl group from the corrinoid protein to CoM. With most other methanogenesis substrates this process is carried out by two different enzymes (for example, EC 2.1.1.90, methanol---corrinoid protein Co-methyltransferase, and EC 2.1.1.246, [methyl-Co(III) methanol-specific corrinoid protein]---coenzyme M methyltransferase). The cobalt is oxidized during methylation from the Co(I) state to the Co(III) state, and is reduced back to the Co(I) form during demethylation.

53414-88-3

methylcobalamin-coenzyme M methyltransferase, EC 2.1.1.246 to EC 2.1.1.253

3-methylmercapto-1-propanol + coenzyme M

methyl-CoM + 3-mercapto-1-propanol

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717563

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?

a [methyl-Co(III) methylated-thiol-specific corrinoid protein] + coenzyme M

methyl-CoM + a [Co(I) methylated-thiol-specific corrinoid protein]

dimethylsulfide + coenzyme M

methyl-CoM + methanethiol

7 entries

methanethiol + a [Co(I) methylated-thiol-specific corrinoid protein]

a [methyl-Co(III) methylated-thiol-specific corrinoid protein] + hydrogen sulfide

methanethiol + coenzyme M

methyl-CoM + hydrogen sulfide

methylmercaptopropionate + coenzyme M

methyl-CoM + mercaptopropionate

additional information

?

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5 entries

a [methyl-Co(III) methylated-thiol-specific corrinoid protein] + coenzyme M

methyl-CoM + a [Co(I) methylated-thiol-specific corrinoid protein]

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-

?

dimethylsulfide + coenzyme M

methyl-CoM + methanethiol

5 entries

methanethiol + a [Co(I) methylated-thiol-specific corrinoid protein]

a [methyl-Co(III) methylated-thiol-specific corrinoid protein] + hydrogen sulfide

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-

?

methanethiol + coenzyme M

methyl-CoM + hydrogen sulfide

methylmercaptopropionate + coenzyme M

methyl-CoM + mercaptopropionate

corrinoid

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the enzyme obligately requires the bound methylated corrinoid cofactor for activity. Corrinoid-dependent methyltransferases cycle between methylated corrinoid in the Co(III) redox state and the highly nucleophilic, reducing, and oxygen-sensitive Co(I) state. In the Co(II) form, these methyltransferase is inactive

additional information

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no corrinoid cofactor bound to the enzyme

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Co3+

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the enzyme obligately requires the bound methylated corrinoid cofactor for activity. Corrinoid-dependent methyltransferases cycle between methylated corrinoid in the Co(III) redox state and the highly nucleophilic, reducing, and oxygen-sensitive Co(I) state. In the Co(II) form, these methyltransferase is inactive

Cobalt

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the enzyme obligately requires the bound methylated corrinoid cofactor for activity. Corrinoid-dependent methyltransferases cycle between methylated corrinoid in the Co(III) redox state and the highly nucleophilic, reducing, and oxygen-sensitive Co(I) state. In the Co(II) form, these methyltransferase is inactive

Zn2+

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one zinc atom per polypeptide

Dimethylsulfide

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inhibits methylcobalamin:coenzyme methyl transfer by MtsA. Inhibition by dimethylsulfide is mixed with respect to methylcobalamin, but competitive with coenzyme M

Ti(III) citrate

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not essential activation

717563

additional information

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5.5

a [Co(I) methylated-thiol-specific corrinoid protein]

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recombinant enzyme, pH 7.0, 37°C

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10.8

coenzyme M

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recombinant enzyme, pH 7.0, 37°C

33

Dimethylsulfide

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recombinant enzyme, pH 7.0, 37°C

10

methylmercaptopropionate

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pH 7.0, 37°C

additional information

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kinetic analysis, overview

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0.078

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purified recombinant enzyme, substrate is dimethylsulfide, pH 7.0, 37°C

7

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assay at

717563, 717763

22

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Cob(I)alamin methylation assay at

37

Methanosarcina barkeri DSM 800

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Methanosarcina barkeri Fusaro, DSM 804

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717563

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culture condition:acetate-grown cell

additional information

evolution

the sequence of MtsA is homologous to the A and M isozymes of methylcobamide:coenzyme M methyltransferases (methyltransferase II), indicating that the alpha polypeptide is a member of the methyltransferase II family of coenzyme M methylases

metabolism

physiological function

6 entries

additional information

41000

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2 * 41000, recombinant enzyme, SDS-PAGE

480000

77000

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recombinant enzyme, gel filtration

homodimer

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2 * 41000, recombinant enzyme, SDS-PAGE

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recombinant MtsA solubilized from inclusion bodies after expression in Escherichia coli strain BL21(DE3)

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gene mtsA, DNA and amino acid sequence determination and analysis, expression in Escherichia coli strain DH5alpha. The gene encoding the alpha subunit of the CoM methylase, mtsA, is 5' to the gene encoding the beta subunit, mtsB, regulated cotranscription of mtsA and mtsB

gene mtsA, functional expression in Escherichia coli strain BL21(DE3)pLysS, MtsA is expressed largely in an insoluble form

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recombinant enzyme from inclusion bodies harvested from cells solubilized using 6 M guanidine hydrochloride, 50 mM DTT, and 20 mM 2-mercaptoethanol. The solubilized protein is diluted 60fold with protein refolding at room temperature for 24 h in refolding buffer consisting of 500 mM Tris, pH 8.0, 1 M KCl, 10 mM DTT, 10 mM 2-mercaptoethanol, and 100 mM ZnCl2. Refolding buffers containing 500 mM guanidine hydrochloride, 33 mM CHAPS, 0.5% Triton X-100, 5 mM SDS, or 20% glycerol do not produce active methyltransferase, nor do refolding at 4°C in the optimal refolding buffer

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