Cloned (Comment) | Organism |
---|---|
overexpression of His-tagged inactive MtaA apoprotein in Escherichia coli strain M15 grown in the presence of 2 mM EDTA | Methanosarcina barkeri |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
EDTA | 75% inhibition at 1 mM, complete inhibition at 2 mM, reversible by Zn2+ addition, competitive versus Zn2+, kinetics, overview | Methanosarcina barkeri | |
additional information | 1 mm nitrilotriacetic acid has almost no effect on the MtaA activity | Methanosarcina barkeri |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Co2+ | required, the apoprotein reacts with zinc or cobalt to the fully active holoenzyme | Methanosarcina barkeri | |
additional information | Zn21 or Co21 are required for MtaA activity, Zn2+ can be replaced by Co2+ but not by Mg2+, the kinetics of activation by Co2+ being similarily slow. About 1 mol of transition metal is bound per mol of protein. The role of the transition metal in MtaA is to lower the microscopic pKa of the thiol group of coenzyme M by coordination to the zinc, and thus to increase its nucleophilicity for methyl group attack, pKZn2+ of MtaA is over 15 | Methanosarcina barkeri | |
Zn2+ | 1 mol per mol of enzyme, required, the apoprotein reacts with zinc or cobalt to the fully active holoenzyme | Methanosarcina barkeri |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
50000 | - |
x * 50000 | Methanosarcina barkeri |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M | Methanosarcina barkeri | - |
methyl-CoM + a [Co(I) methanol-specific corrinoid protein] | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Methanosarcina barkeri | - |
gene mtaA | - |
Purification (Comment) | Organism |
---|---|
recombinant His-tagged apo MtaA from Escherichia coli strain M15 by nickel affinity and anionexchange chromatography | Methanosarcina barkeri |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
a [methyl-Co(III) methanol-specific corrinoid protein] + CoM = methyl-CoM + a [Co(I) methanol-specific corrinoid protein] | coenzyme M binds with its thiol group to the zinc in the active site of MtaA forming a coenzyme M thiolate zinc complex | Methanosarcina barkeri |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
2 | - |
purified Zn2+-containing holoenzyme, pH 7.0, 37°C | Methanosarcina barkeri |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
a [methyl-Co(III) methanol-specific corrinoid protein] + coenzyme M | - |
Methanosarcina barkeri | methyl-CoM + a [Co(I) methanol-specific corrinoid protein] | - |
? |
Subunits | Comment | Organism |
---|---|---|
? | x * 50000 | Methanosarcina barkeri |
Synonyms | Comment | Organism |
---|---|---|
mtaA | - |
Methanosarcina barkeri |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Methanosarcina barkeri |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7 | - |
assay at | Methanosarcina barkeri |
General Information | Comment | Organism |
---|---|---|
additional information | MtaC and MtaB form a tight complex and the encoding genes form a transcription unit, whereas MtaA purifies separately and its encoding gene is located separately | Methanosarcina barkeri |
physiological function | the methyltransferase designated MtaA together with the proteins MtaB and MtaC mediate the formation of methyl-coenzyme M from methanol and coenzyme M. MtaC is a 28-kDa corrinoid protein, MtaB, EC 2.1.1.90, catalyzes the methylation of MtaC and MtaA catalyzes the demethylation of methylated MtaC | Methanosarcina barkeri |