Information on EC 2.1.1.248 - methylamine-corrinoid protein Co-methyltransferase

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The expected taxonomic range for this enzyme is: Methanosarcina

EC NUMBER
COMMENTARY hide
2.1.1.248
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RECOMMENDED NAME
GeneOntology No.
methylamine-corrinoid protein Co-methyltransferase
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REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
methylamine + a [Co(I) methylamine-specific corrinoid protein] = a [methyl-Co(III) methylamine-specific corrinoid protein] + NH3
show the reaction diagram
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Methane metabolism
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methanogenesis from methylamine
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Microbial metabolism in diverse environments
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SYSTEMATIC NAME
IUBMB Comments
monomethylamine:5-hydroxybenzimidazolylcobamide Co-methyltransferase
The enzyme, which catalyses the transfer of a methyl group from methylamine to a methylamine-specific corrinoid protein (MtmC), is involved in methanogenesis from methylamine. The enzyme contains the unusual amino acid pyrrolysine [3]. 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. The methylated corrinoid protein is substrate for EC 2.1.1.247, methylated methylamine-specific corrinoid protein:coenzyme M methyltransferase.
CAS REGISTRY NUMBER
COMMENTARY hide
53414-88-3
methylcobalamin-coenzyme M methyltransferase, EC 2.1.1.246 to EC 2.1.1.253
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
DSM 3647, genes mtmB1C1 and mtmB2C2
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Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
metabolism
physiological function
additional information
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
methylamine + a [Co(I) methylamine-specific corrinoid protein]
a [methyl-Co(III) methylamine-specific corrinoid protein] + ammonia
show the reaction diagram
additional information
?
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model for MtmB methylation of Co(I) corrinoid cofactor with monomethylamine. Y335 and Q333 are proposed to assist in the initial MtmB binding of monomethylamine and positioning such that electrophilic attack of the C-2 atom on the lone electron pair of the nitrogen of unionized monomethylamine occurs. The residues can also serve to H-bond with the ammonia released from the pyrroline ring, enhancing the equilibrium between 2-aminopyrrolysine and pyrrolysine in the direction of product removal from the enzyme, model of pyrrolysine function
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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
methylamine + a [Co(I) methylamine-specific corrinoid protein]
a [methyl-Co(III) methylamine-specific corrinoid protein] + ammonia
show the reaction diagram
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
RamA
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a 60-kDa monomeric iron sulfur protein, is a protein required for reductive activation of corrinoid-dependent methylamine methyltransferase reactions in methanogenic archaea, it is required for in vitro ATP-dependent reductive activation of methylamine:CoM methyl transfer mediating the ATP-dependent reductive activation of Co(II) corrinoid to the Co(I) state for the monomethylamine corrinoid protein, MtmC, overview. RamA affects both lag times and rates during assay of MMA:CoM methyl transfer
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SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.49
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purified native enzyme, pH 7.0, 37°C
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
52000
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3 * 52000
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
homotrimer
additional information
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
crystal structure determination and analysis
two crystal forms of MtmB obtained from solutions containing NaCl or (NH4)2SO4. In the NaCl crystal form, the pyrroline is unmodified at the C-2 position. The second crystal form is a mixture of two pyrrolysine states. Crystal structure analysis, overview
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
native enzyme, separation from co-purifiying MtmC, the methylamine-specific corrinoid protein, by gel filtration
native MtmB from monomethylamine-grown cells, by two different steps of anionexchange chromatography, followed by gel filtration and another step of anion exchange chromatography to near homogeneity
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native MtmB from monomethylamine-grown cells, by two different steps of anionexchange chromatography, followed by gel filtration and another step of anion exchange chromatography to near homogeneity, co-purification with the monomethylamine-specific corrinoid protein MtmC
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
gene mtmB, DNA and amino acid sequence determination and analysis, genetic organization, the open reading frame of mtmB is interrupted by a single in-frame, midframe, UAG codon. A mechanism that circumvents UAG-directed termination of translation must operate during expression of mtmB in this methanogen. Analysis of the clustered genes encoding the methyltransferases of methanogenesis from monomethylamine and determination of transcript start sites. Cloning and expression of MtmB in Escherichia coli strain DH5alpha
gene mtmB1, DNA and amino acid sequence determination and analysis, UAG is not the stop codon in the encoding gene, no UAG modification. The mtmB1 amber codon encodes pyrrolysine in UAG, crystal structure of MtmB reveals lysine, but with epsilonN in amide linkage with (4R,5R)-4 substituted-pyrroline-5-carboxylate
gene mtmB1and mtmB2C2, operon encoding MMA methylamine methyltransferase, quantitative RT-PCR expression analysis, comparison with other methylamine methyltransferases, overview. Transcriptional regulation of genes encoding methylamine methyltransferases in cells growing on Ttrimethyamine or methanol in the presence of ammonium, overview
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EXPRESSION
ORGANISM
UNIPROT
LITERATURE
transcription of the mtmB1C1 operon is not affected by the nitrogen source but appears to be increased when trimethylamine is the sole carbon and energy source. Under nitrogen limitation, a 543fold up-regulation of the mtmB2C2 operon encoding MMA methyltransferase 2 is obtained when methanol was used as carbon source, whereas transcription of the homologous mtmB1C1 operon occurs at a constant level independently of the nitrogen source
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