Information on EC 2.1.1.90 - methanol-corrinoid protein Co-methyltransferase

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The expected taxonomic range for this enzyme is: Bacteria, Archaea

EC NUMBER
COMMENTARY hide
2.1.1.90
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RECOMMENDED NAME
GeneOntology No.
methanol-corrinoid protein Co-methyltransferase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
methanol + a [Co(I) methanol-specific corrinoid protein] = a [methyl-Co(III) methanol-specific corrinoid protein] + H2O
show the reaction diagram
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REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
methyl group transfer
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
methanogenesis from methanol
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Methane metabolism
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Microbial metabolism in diverse environments
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SYSTEMATIC NAME
IUBMB Comments
methanol:5-hydroxybenzimidazolylcobamide Co-methyltransferase
The enzyme, which catalyses the transfer of methyl groups from methanol to a methanol-specific corrinoid protein (MtaC), is involved in methanogenesis from methanol. Methylation of the corrinoid protein requires the central cobalt to be in the Co(I) state. During methylation the cobalt is oxidized to the Co(III) state. Free cob(I)alamin can substitute for the corrinoid protein in vitro [2]. Inactivated by oxygen and other oxidizing agents, and reactivated by catalytic amounts of ATP and hydrogen.
CAS REGISTRY NUMBER
COMMENTARY hide
86611-98-5
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GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
physiological function
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
methanol + 5-hydroxybenzimidazolylcobamide
Co-methyl-Co-5-hydroxybenzimidazolylcobamide + H2O
show the reaction diagram
methanol + a [Co(I) methanol-specific corrinoid protein]
a [methyl-Co(III) methanol-specific corrinoid protein] + H2O
show the reaction diagram
methanol + cob(I)alamin
methyl-cob(III)alamin + H2O
show the reaction diagram
additional information
?
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analysis of mtaCB gene regulation in Methanosarcina acetivorans
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NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
methanol + 5-hydroxybenzimidazolylcobamide
Co-methyl-Co-5-hydroxybenzimidazolylcobamide + H2O
show the reaction diagram
methanol + a [Co(I) methanol-specific corrinoid protein]
a [methyl-Co(III) methanol-specific corrinoid protein] + H2O
show the reaction diagram
additional information
?
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analysis of mtaCB gene regulation in Methanosarcina acetivorans
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COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
5-Hydroxybenzimidazolylcobamide
corrinoid
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the enzyme only binds the methyl group of methanol when the cobalt atom of its corrinoid prosthetic groups is present in the highly reduced Co(I) state. Formation of this redox state requires H2, hydrogenase, methyltransferase activation protein, and ATP. Purified enzyme contains 1.7 corrinoids per enzyme with cobalt in the fully oxidized Co(III) state. Water and N-3 of the 5-hydroxybenzimidazolyl base serve as the upper and lower ligands, respectively. Reduction to the Co(II) level is accomplished by H2 and hydrogenase. The cob(II)amide of the enzyme has the base coordinated at this stage. Subsequent addition of methyltransferase activation protein and ATP results in the formation of base-uncoordinated Co(II) enzyme
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Ba2+
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metal-free enzyme preparation has no activity, addition of Ba2+ restores 27% of the original activity
Ca2+
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metal-free enzyme preparation has no activity, addition of Ca2+ restores 35% of the original activity
Co2+
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metal-free enzyme preparation has no activity, addition of Co+ restores 46% of the original activity
Cobalt
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the enzyme only binds the methyl group of methanol when the cobalt atom of its corrinoid prosthetic groups is present in the highly reduced Co(I) state. Formation of this redox state requires H2, hydrogenase, methyltransferase activation protein, and ATP
Iron
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presence of 1.7 mol of non-heme iron per mol of enzyme
Mn2+
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metal-free enzyme preparation has no activity, addition of Mn2+ restores 27% of the original activity
Ni2+
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metal-free enzyme preparation has no activity, addition of Ni2+ restores 21% of the original activity
Sr2+
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metal-free enzyme preparation has no activity, addition of Sr2+ restores 20% of the original activity
Zinc
dependent on
Zn2+
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beta subunit MtaB contains 1 mol Zn2+/mol subunit, Zn2+ can be substituted by Co2+
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
HgCl2
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1 mM, 90% inhibition
Na2SO3
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1 mM, 50% inhibition
NaNO2
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0.1 mM, 90% inhibition
NH4Cl
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400 mM, 93% inhibition
O2
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inactivation by O2 and other oxidizing agents
pyridoxal 5'-phosphate
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1 mM, 74% inhibition
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
ATP
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half-maximal activation at 0.16 mM ATP
additional information
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
40
methanol
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beta subunit MtaB
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pI VALUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
4.5
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isoelectric focusing
PDB
SCOP
CATH
ORGANISM
UNIPROT
Methanosarcina barkeri (strain Fusaro / DSM 804)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
121000
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gradient PAGE, gel filtration
122000
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
trimer
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
hanging drop vapor diffusion method, 2.5 A crystal structure of the methanol-activating MtaBC complex from Methanosarcina barkeri composed of the zinc-containing MtaB and the 5-hydroxybenzimidazolylcobamide-carrying MtaC subunits. Crystal structure of this complex organized as a (MtaBC)2 heterotetramer. MtaB folds as a TIM barrel and contains a novel zinc-binding motif. Zinc(II) lies at the bottom of a funnel formed at the C-terminal beta-barrel end and ligates to two cysteinyl sulfurs (Cys-220 and Cys-269) and one carboxylate oxygen (Glu-164)
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GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
presence of divalent cations e.g. Mg2+, Mn2+, Sr2+, Ca2+ or Ba2+ are required for stability
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OXIDATION STABILITY
ORGANISM
UNIPROT
LITERATURE
oxygen-sensitive
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485662, 485660
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expression of beta subunit MtaB in Escherichia coli
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EXPRESSION
ORGANISM
UNIPROT
LITERATURE
methanol-specific methyltransferase MT1 isozymes are encoded by three operons mtaCB1, mtaCB2, and mtaCB3. When expressed from the strong PmtaC1 or PmtaC2 promoter, each of the MtaC and MtaB proteins supports growth and methane production at wild-type levels. In contrast, all mtaCB operons exhibit poorer growth and lower rates of methane production when PmtaC3 controlls their expression. All combinations of MtaC, MtaB, and MtaA can form functional methyltransferase MT1/MT2 complexes. Variations in enzyme activity correlate with differences in protein abundance. The mtaCBA transcripts show different stabilities, which are strongly influenced by the growth substrate
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