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Literature summary extracted from

  • Krzycki, J.
    Function of genetically encoded pyrrolysine in corrinoid-dependent methylamine methyltransferases (2004), Curr. Opin. Chem. Biol., 8, 484-491.
    View publication on PubMed

Cloned(Commentary)

EC Number Cloned (Comment) Organism
2.1.1.248 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 Methanosarcina barkeri
2.1.1.249 gene mtbB, DNA and amino acid sequence determination and analysis, UAG is not the stop codon in the encoding gene, no UAG modification Methanosarcina barkeri

Crystallization (Commentary)

EC Number Crystallization (Comment) Organism
2.1.1.248 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 Methanosarcina barkeri

Molecular Weight [Da]

EC Number Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
2.1.1.248 50000
-
 3 * 50000 Methanosarcina barkeri
2.1.1.249 50000
-
 1 * 50000 Methanosarcina barkeri
2.1.1.250 50000
-
 1 * 50000 Methanosarcina barkeri

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2.1.1.248 methylamine + a [Co(I) methylamine-specific corrinoid protein] Methanosarcina barkeri
-
 a [methyl-Co(III) methylamine-specific corrinoid protein] + ammonia
-
 ?
2.1.1.249 dimethylamine + a [Co(I) dimethylamine-specific corrinoid protein] Methanosarcina barkeri
-
 a [methyl-Co(III) dimethylamine-specific corrinoid protein] + methylamine
-
 ?
2.1.1.250 trimethylamine + a [Co(I) methylamine-specific corrinoid protein] Methanosarcina barkeri
-
 a [methyl-Co(III) methylamine-specific corrinoid protein] + dimethylamine
-
 ?

Organism

EC Number Organism UniProt Comment Textmining
2.1.1.248 Methanosarcina barkeri O30642 gene mtmB1
-
2.1.1.249 Methanosarcina barkeri O30642 gene mtbB
-
2.1.1.250 Methanosarcina barkeri O93658 gene mttB
-

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2.1.1.248 methylamine + a [Co(I) methylamine-specific corrinoid protein]
-
 Methanosarcina barkeri a [methyl-Co(III) methylamine-specific corrinoid protein] + ammonia
-
 ?
2.1.1.248 methylamine + a [Co(I) methylamine-specific corrinoid protein] the methylamine-specific corrinoid protein MtmC cycles between methyl-Co(III)- and Co(I)-MtmC during catalysis. Methanogen methylotrophic corrinoid proteins such as MtmC are methylated in the Co(I) state, forming a hexacoordinate methyl-Co(III) species whose demethylation regenerates Co (I) corrinoid. Pyrrolysine in MtmB mediates methylation of MtmC Methanosarcina barkeri a [methyl-Co(III) methylamine-specific corrinoid protein] + ammonia
-
 ?
2.1.1.248 additional information 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 Methanosarcina barkeri ?
-
 ?
2.1.1.249 dimethylamine + a [Co(I) dimethylamine-specific corrinoid protein]
-
 Methanosarcina barkeri a [methyl-Co(III) dimethylamine-specific corrinoid protein] + methylamine
-
 ?
2.1.1.250 trimethylamine + a [Co(I) methylamine-specific corrinoid protein]
-
 Methanosarcina barkeri a [methyl-Co(III) methylamine-specific corrinoid protein] + dimethylamine
-
 ?

Subunits

EC Number Subunits Comment Organism
2.1.1.248 homotrimer 3 * 50000 Methanosarcina barkeri
2.1.1.248 More tertiary structures of MtmB and its substrate, MtmC Methanosarcina barkeri
2.1.1.249 monomer 1 * 50000 Methanosarcina barkeri
2.1.1.250 monomer 1 * 50000 Methanosarcina barkeri

Synonyms

EC Number Synonyms Comment Organism
2.1.1.248 MMA methyltransferase
-
 Methanosarcina barkeri
2.1.1.248 MtmB
-
 Methanosarcina barkeri
2.1.1.249 DMA methyltransferase
-
 Methanosarcina barkeri
2.1.1.249 MtbB
-
 Methanosarcina barkeri
2.1.1.250 MttB
-
 Methanosarcina barkeri
2.1.1.250 TMA methyltransferase
-
 Methanosarcina barkeri

General Information

EC Number General Information Comment Organism
2.1.1.248 metabolism biochemistry of methane formation by Methanosarcina species from monomethylamine, dimethylamine, and trimethylamine: methanogenesis from these substrates is initiated by three methyltransferases that specifically methylate their cognate corrinoid proteins with one of these methylamines, cf. EC 2.1.1.250 and EC 2.1.1.249, overview Methanosarcina barkeri
2.1.1.248 additional information the enzyme contains pyrrolysine at the UAG posotion, crystal structure of MtmB reveals lysine, but with epsilonN in amide linkage with (4R,5R)-4 substituted-pyrroline-5-carboxylate Methanosarcina barkeri
2.1.1.248 physiological function the enzyme is involved in the corrinoid-dependent demethylation of methylamines, which are used for coenzyme M methylation, homology modeling of MtmC, the methylamine-specific corrinoid protein. Pyrrolysine in MtmB mediates methylation of MtmC Methanosarcina barkeri
2.1.1.249 metabolism biochemistry of methane formation by Methanosarcina species from monomethylamine, dimethylamine, and trimethylamine: methanogenesis from these substrates is initiated by three methyltransferases that specifically methylate their cognate corrinoid proteins with one of these methylamines, cf. EC 2.1.1.250 and EC 2.1.1.248, overview Methanosarcina barkeri
2.1.1.249 physiological function the enzyme is involved in the corrinoid-dependent demethylation of methylamines, which are used for coenzyme M methylation Methanosarcina barkeri
2.1.1.250 metabolism biochemistry of methane formation by Methanosarcina species from monomethylamine, dimethylamine, and trimethylamine: methanogenesis from these substrates is initiated by three methyltransferases that specifically methylate their cognate corrinoid proteins with one of these methylamines, cf. EC 2.1.1.248 and EC 2.1.1.249, overview Methanosarcina barkeri
2.1.1.250 physiological function the enzyme is involved in the corrinoid-dependent demethylation of methylamines, which are used for coenzyme M methylation Methanosarcina barkeri