Catalyses the transfer of a methyl group from the cobamide cofactor of a corrinoid/Fe-S protein to the N5 group of tetrahydrosarcinapterin. Forms, together with EC 1.2.7.4, anaerobic carbon-monoxide dehydrogenase, and EC 2.3.1.169, CO-methylating acetyl-CoA synthase, the acetyl-CoA decarbonylase/synthase complex that catalyses the demethylation of acetyl-CoA in a reaction that also forms CO2. This reaction is a key step in methanogenesis from acetate.
The expected taxonomic range for this enzyme is: Archaea, Bacteria
5-methyltetrahydrosarcinapterin:corrinoid/iron-sulfur protein Co-methyltransferase (EC 2.1.1.245), carbon-monoxide dehydrogenase (ferredoxin) (EC 1.2.7.4) and CO-methylating acetyl-CoA synthase (EC 2.3.1.169) form together the acetyl-CoA decarbonylase/synthase complex that catalyses the demethylation of acetyl-CoA in a reaction that also forms CO2
5-methyltetrahydrosarcinapterin:corrinoid/iron-sulfur protein Co-methyltransferase (EC 2.1.1.245), carbon-monoxide dehydrogenase (ferredoxin) (EC 1.2.7.4) and CO-methylating acetyl-CoA synthase (EC 2.3.1.169) form together the acetyl-CoA decarbonylase/synthase complex that catalyses the demethylation of acetyl-CoA in a reaction that also forms CO2
a [methyl-Co(III) corrinoid Fe-S protein] + tetrahydrosarcinapterin = a [Co(I) corrinoid Fe-S protein] + 5-methyltetrahydrosarcinapterin
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a [methyl-Co(III) corrinoid Fe-S protein] + tetrahydrosarcinapterin = a [Co(I) corrinoid Fe-S protein] + 5-methyltetrahydrosarcinapterin
random Bi-Bi mechanism of transfer of the methyl group from (6S)-methyltetrahydrofolate to the corrinoid/iron-sulfur protein: CH3-H4folate binds to MeTr in the unprotonated form and then undergoes rapid protonation. This protonation enhances the electrophilicity of the methyl group, in agreement with a 10fold increase in the pKa at N5 of CH3-H4folate. Next, the Co(I)-CFeSP attacks the methyl group in a rate-limiting SN2 reaction to form methylcob(III)amide. Finally, the products randomly dissociate. A pH-dependent conformational change is required for methyl transfer in the forward and reverse directions, a rate-limiting ionization of MeTr, not of CH3-H4folate, is responsible for the pH dependence of the methyl transfer reaction
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SYSTEMATIC NAME
IUBMB Comments
5-methyltetrahydrosarcinapterin:corrinoid/iron-sulfur protein methyltransferase
Catalyses the transfer of a methyl group from the cobamide cofactor of a corrinoid/Fe-S protein to the N5 group of tetrahydrosarcinapterin. Forms, together with EC 1.2.7.4, anaerobic carbon-monoxide dehydrogenase, and EC 2.3.1.169, CO-methylating acetyl-CoA synthase, the acetyl-CoA decarbonylase/synthase complex that catalyses the demethylation of acetyl-CoA in a reaction that also forms CO2. This reaction is a key step in methanogenesis from acetate.
Substrates: the reaction is performed by the intact gamma subunit and fragments of the delta subunit, components of the proteolyzed acetyl-CoA decarbonylase synthase, ACDS, complex, overview Products: -
r
a [methyl-Co(III) corrinoid Fe-S protein] + tetrahydrosarcinapterin
a [Co(I) corrinoid Fe-S protein] + 5-methyltetrahydrosarcinapterin
Substrates: structures of tetrahydrosarcinapterin and N5-methyl-tetrahydrosarcinapterin, overview. The reaction is performed by the intact gamma subunit and fragments of the delta subunit, components of the proteolyzed acetyl-CoA decarbonylase synthase, ACDS, complex, overview Products: -
r
a [methyl-Co(III) corrinoid Fe-S protein] + tetrahydrosarcinapterin
a [Co(I) corrinoid Fe-S protein] + 5-methyltetrahydrosarcinapterin
Substrates: a pH-dependent conformational change is required for methyl transfer in the forward and reverse directions, but this step is not rate-limiting Products: -
r
a [methyl-Co(III) corrinoid Fe-S protein] + tetrahydrosarcinapterin
a [Co(I) corrinoid Fe-S protein] + 5-methyltetrahydrosarcinapterin
Substrates: a pH-dependent conformational change is required for methyl transfer in the forward and reverse directions, but this step is not rate-limiting, the pH-dependent protein conformational change in the ternary complex is linked to deprotonation of the active complexes Products: -
Substrates: reduction of the cobalt atom of the corrinoid to Co1+ by Ti(III)citrate, the gamma subunit CdhE contains the single 4Fe-4S center in the C/Fe-S enzyme Products: -
Substrates: reduction of the cobalt atom of the corrinoid to Co1+ by Ti(III)citrate, the gamma subunit CdhE contains the single 4Fe-4S center in the C/Fe-S enzyme Products: -
Substrates: the methyltetrahydrofolate:corrinoid/iron-sulfur protein methyltransferase catalyzes transfer of the N5-methyl group from (6S)-methyltetrahydrofolate, i.e. CH3-H4folate, to the cobalt center of a corrinoid/iron-sulfur protein, CFeSP, forming methylcob(III)-amide and H4folate Products: -
Substrates: the reaction is performed by the intact gamma subunit and fragments of the delta subunit, components of the proteolyzed acetyl-CoA decarbonylase synthase, ACDS, complex, overview Products: -
r
a [methyl-Co(III) corrinoid Fe-S protein] + tetrahydrosarcinapterin
a [Co(I) corrinoid Fe-S protein] + 5-methyltetrahydrosarcinapterin
Substrates: a pH-dependent conformational change is required for methyl transfer in the forward and reverse directions, but this step is not rate-limiting Products: -
single-turnover stopped-flow studies, steady-state and pre-steady-state kinetic studies at different pH values and by kinetic simulations, random Bi-Bi reaction mechanism, detailed overview
the enzyme reaction initiates the unusual biological organometallic reaction sequence that constitutes the Wood-Ljungdahl or reductive acetyl-CoA pathway
genes cdhD and cdhE encode the delta and gamma subunits of the C/Fe-S enzyme from the CO dehydrogenase complex of Methanosarcina thermophila, the complex comprises a nickel/iron-sulfur, Ni/Fe-S, enzyme containing alpha and epsilon subunits and a corrinoid/iron-sulfur, C/Fe-S, enzyme containing gamma and delta subunits. The C/Fe-S enzyme purified contains one molecule of factor III in the base-off form which facilitates reduction of the cobalt atom to the Co1+ redox state, which is a requirement for methylation. The gamma subunit CdhE contains the single 4Fe-4S center in the C/Fe-S enzyme
genes cdhD and cdhE encode the delta and gamma subunits of the C/Fe-S enzyme from the CO dehydrogenase complex of Methanosarcina thermophila, the complex comprises a nickel/iron-sulfur, Ni/Fe-S, enzyme containing alpha and epsilon subunits and a corrinoid/iron-sulfur, C/Fe-S, enzyme containing gamma and delta subunits. The C/Fe-S enzyme purified contains one molecule of factor III in the base-off form which facilitates reduction of the cobalt atom to the Co1+ redox state, which is a requirement for methylation. The gamma subunit CdhE contains the single 4Fe-4S center in the C/Fe-S enzyme
genes cdhD and cdhE encode the delta and gamma subunits of the C/Fe-S enzyme from the CO dehydrogenase complex of Methanosarcina thermophila, the complex comprises a nickel/iron-sulfur, Ni/Fe-S, enzyme containing alpha and epsilon subunits and a corrinoid/iron-sulfur, C/Fe-S, enzyme containing gamma and delta subunits. The C/Fe-S enzyme contains one molecule of factor III in the base-off form which facilitates reduction of the cobalt atom to the Co1+ redox state, which is a requirement for methylation. The gamma subunit CdhE contains the single 4Fe-4S center in the C/Fe-S enzyme, overview
genes cdhD and cdhE encode the delta and gamma subunits of the C/Fe-S enzyme from the CO dehydrogenase complex of Methanosarcina thermophila, the complex comprises a nickel/iron-sulfur, Ni/Fe-S, enzyme containing alpha and epsilon subunits and a corrinoid/iron-sulfur, C/Fe-S, enzyme containing gamma and delta subunits. The C/Fe-S enzyme contains one molecule of factor III in the base-off form which facilitates reduction of the cobalt atom to the Co1+ redox state, which is a requirement for methylation. The gamma subunit CdhE contains the single 4Fe-4S center in the C/Fe-S enzyme, overview
the C/Fe-S enzyme purified contains one molecule of factor III in the base-off form which facilitates reduction of the cobalt atom to the Co1+ redox state, which is a requirement for methylation
the C/Fe-S enzyme purified contains one molecule of factor III in the base-off form which facilitates reduction of the cobalt atom to the Co1+ redox state, which is a requirement for methylation
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CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
genes cdhE and cdhD, the cdhD gene is located upstream of cdhE, DNA and amino acid sequence determination and analysis, expression in Escherichia coli strain BL21(DE3)
Mechanism of transfer of the methyl group from (6S)-methyltetrahydrofolate to the corrinoid/iron-sulfur protein catalyzed by the methyltransferase from Clostridium thermoaceticum: a key step in the Wood-Ljungdahl pathway of acetyl-CoA synthesis
Characterization of the cdhD and cdhE genes encoding subunits of the corrinoid/iron-sulfur enzyme of the CO dehydrogenase complex from Methanosarcina thermophila
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