Coenzyme M methylase activity of the 480-kilodalton corrinoid protein from Methanosarcina barkeri

Tallant, Thomas C.; Krzycki, Joseph A.

doi:10.1128/jb.178.5.1295-1301.1996

Cited by 23 publications

(41 citation statements)

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“…Such a modular structure is found in other cobalamin-dependent methyltransferases, e.g. the membrane-bound N5-methyltetrahydromethanopterin methyltransferase from Methanobacterium therrnoautotrophicum (Harms and Thauer, 1996b), the trimethylamine :coenzyme M methyltransferase from M. barkeri (Ferguson and Krzycki, 1997) and the methanethiol :coenzyme M methyltransferase from M. harkeri (Tallant and Krzycki, 1996). For cobalamindependent methionine synthase from E. coli, which is composed of only one polypeptide of molecular mass 136 kDa, there is evidence that methyltetrahydrofolate and homocysteine activation and cobalamin binding are each mediated by a different part of the polypeptide chain (Luschinsky Drennan et al, 1994;Dixon et al, 1996;Goulding et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

“…To determine whether MtaB or MtaC or both are required for methyl transfer from methanol to cob(I)alamin, purified MTI from M. barkeri was subjected to SDSPAGE and the separated subunits tested with an activity stain for methyltransferase activity using methylcobalamin and nitroblue tetrazolium (Tallant and Krzycki, 1996). Demethylation of methylcobalamin yields cob(I)alamin, which reduces the colourless soluble nitroblue tetrazolium to the dark blue and insoluble bisformazan.…”

Section: Resultsmentioning

confidence: 99%

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Methanol: Coenzyme M Methyltransferase from Methanosarcina Barkeri

Sauer

Thauer

1997

European Journal of Biochemistry

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In Methanosarcina barkeri, methanogenesis from methanol is initiated by the formation of methylcoenzyme M from methanol and coenzyme M. This methyl transfer reaction is catalyzed by two enzymes, designated methyltransferases 1 (MT1) and 2 (MT2). Transferase MT1, which is composed of a 50-kDa subunit, MtaB, and a 27-kDa corrinoid-harbouring subunit, MtaC, has been shown recently to catalyze the methylation of free cob(1)alamin with methanol [Sauer, K., Harms, U. & Thauer, R. K. (1997) Eui: J. Biochem. 243, 670-6771. We report here that this reaction is catalyzed by subunit MtaB overproduced in Escherichiu coli. MtaB also catalyzed the formation of methanol from methylcobalamin and H20, the hydrolysis being associated with a free-energy change AGO' of approximately +7.0 kJ/mol. MtaB was found to contain 1 mol zinc, and its activity to be zinc dependent (pK,,,x+ = 9.3). The zinc dependence of the MT2 (MtaA)-catalyzed reaction is also described (pK,,,.+ = 9.6).

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Section: Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Methanol: Coenzyme M Methyltransferase from Methanosarcina Barkeri

Sauer

Thauer

1997

European Journal of Biochemistry

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“…The enzymes catalysing its methylation and reductive demethylation are highly specific for its structure. 2-Selenoethanesulphonate and 3-thiopropionate can in part substitute for H-S-CoM in its function, 3-thiopropanesulphonate cannot (Gunsalus et al, 1978 ;Wackett et al, 1987;Tallant & Krzycki, 1996. Table 5.…”

Section: Methyl-coenzyme M An Intermediate Unique To Methanogenesismentioning

confidence: 99%

“…S Also catalyses the methylation of coenzyme M with methylmercaptopropanol (95 % ), methylmercaptopropionate (80 */o ), mercaptomethanol (lo%), methylmercaptoethanol (8 %) and methyliodide (170 %) (Tallant & Krzycki, 1997) and the methylation of mercaptoethanol (27 %) and 2-mercaptopropanol (66 %) (Tallant & Krzycki, 1996).…”

Section: Reactionmentioning

confidence: 99%

Biochemistry of methanogenesis: a tribute to Marjory Stephenson:1998 Marjory Stephenson Prize Lecture

1998

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Historical overview In 1933, Stephenson & Stickland (1933a) published that they had isolated from river mud, by the single cell technique, a methanogenic organism capable of growth in an inorganic medium with formate as the sole carbon source. 4 H C 0 0-+ 4H' + CH, + 3 C 0 , + 2H,O AGO' =-144-5 kJ mol-' Methane formation from formate was shown to occur in a stepwise manner, by the preliminary decomposition of formic acid into CO, and H, followed by a reduction of CO, by H,, suggesting that formate was not an intermediate in the reduction of CO, to methane. HCOO-+ H+-+ H, + CO, 4H,+CO,-+ C H , + 2 H 2 0 AGO' =-3-5 kJ mol-' AGO' =-131 kJ mol-' Cell suspensions of the microorganism catalysed the reduction of methylene blue with H,, indicating that the methanogen contained an enzyme which activates molecular hydrogen. H,-+ 2e-+ 2H+ E; =-414mV This enzyme had been discovered by Stephenson & Stickland (1931a) 2 years before in a number of bacterial species and was named by them 'hydrogenase'. The paper by Stephenson & Stickland (1933a) is considered to mark the beginning of the modern era for study of methanogenesis (Wolfe, 1993). It is the first Except when otherwise noted, the free energy changes given for methanogenic reactions were calculated from the free energies of formation from the elements of the substrates and products with non-gaseous compounds at 1 M aqueous solution and gaseous compounds in the gaseous state at 1 atmosphere pressure (101 kPa). The free energy changes of formation were taken from Thauer eta/. (1977). 0002-2667 0 1998 SGM Glucose-+ 3C0, + 3CH, AGO' =-418.1 kJ mol-' This reaction is not catalysed by single microorganisms but by syntrophic associations of microorganisms. First the glucose is fermented to acetate, CO, and H, or to acetate, formate and H, : Glucose + 2H,O + 2CH3COO-+ 2H' + 2C0, + 4H2 AGO' =-215.7 kJ mol-' Glucose + 2H20-+ 2CH3COO-+ 2HC00-+ 4H' + 2H, AGO' =-208.7 kJ mol-1 These fermentations are brought about by strictly anaerobic bacteria and/or protozoa. In a second step, the products of glucose fermentation are then converted to methane, the rate of conversion being such that the concentrations of acetate (< 1 mM), formate (< 0.1 mM) and H, (< 1 pM) in the anaerobic sediments remain very low (Zinder, 1993). CH3COO-+Hf-+ C02+CH, AGO' =-36 kJ mol-' 4H, + CO,-+ CH, + 2H20 AGO' =-131 kJ mol-' 4HC00-+4H+ + CH,+3C02+2H,0 AGO' =-144.5 kJ mol-' H-S-CoM, coenzyme M ; H-S-COB, coenzyme B ; H,SPT, tetrahydrosarcinapterin, which is the modified tetrahydromethanopterin (for structures see Fig. 3) present in the Methanosarcinales (Gorris & van der Drift, 1994). Reaction" Enzyme (gene) Most recent literature Acetate + CoA + acetyl-CoA + H,O AGO' = + 35.7 k J rnol-lt

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“…Methyl-MtaC is then demethylated by a different CoM methylase, MtaA, which methylates CoM. Methylthiol:CoM methyl transfer has been shown to require only two polypeptides (39,40). In this case, a third CoM methylase, MtsA, appears to methylate a corrinoid binding protein, MtsB, with methylated thiols like dimethylsulfide (MtsB is the only corrinoid protein which is not named according to the above nomenclature rules).…”

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confidence: 99%

The Trimethylamine Methyltransferase Gene and Multiple Dimethylamine Methyltransferase Genes of Methanosarcina barkeri Contain In-Frame and Read-Through Amber Codons

2000

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Three different methyltransferases initiate methanogenesis from trimethylamine (TMA), dimethylamine (DMA) or monomethylamine (MMA) by methylating different cognate corrinoid proteins that are subsequently used to methylate coenzyme M (CoM). Here, genes encoding the DMA and TMA methyltransferases are characterized for the first time. A single copy of mttB, the TMA methyltransferase gene, was cotranscribed with a copy of the DMA methyltransferase gene, mtbB1. However, two other nearly identical copies of mtbB1, designated mtbB2 and mtbB3, were also found in the genome. A 6.8-kb transcript was detected with probes to mttB and mtbB1, as well as to mtbC and mttC, encoding the cognate corrinoid proteins for DMA:CoM and TMA:CoM methyl transfer, respectively, and with probes to mttP, encoding a putative membrane protein which might function as a methylamine permease. These results indicate that these genes, found on the chromosome in the order mtbC, mttB, mttC, mttP, and mtbB1, form a single transcriptional unit. A transcriptional start site was detected 303 or 304 bp upstream of the translational start of mtbC. The MMA, DMA, and TMA methyltransferases are not homologs; however, like the MMA methyltransferase gene, the genes encoding the DMA and TMA methyltransferases each contain a single in-frame amber codon. Each of the three DMA methyltransferase gene copies from Methanosarcina barkeri contained an amber codon at the same position, followed by a downstream UAA or UGA codon. The C-terminal residues of DMA methyltransferase purified from TMA-grown cells matched the residues predicted for the gene products of mtbB1, mtbB2, or mtbB3 if termination occurred at the UAA or UGA codon rather than the in-frame amber codon. The mttB gene from Methanosarcina thermophila contained a UAG codon at the same position as the M. barkeri mttB gene. The UAG codon is also present in mttB transcripts. Thus, the genes encoding the three types of methyltransferases that initiate methanogenesis from methylamine contain in-frame amber codons that are suppressed during expression of the characterized methyltransferases.

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Coenzyme M methylase activity of the 480-kilodalton corrinoid protein from Methanosarcina barkeri

Cited by 23 publications

References 40 publications

Methanol: Coenzyme M Methyltransferase from Methanosarcina Barkeri

Methanol: Coenzyme M Methyltransferase from Methanosarcina Barkeri

Biochemistry of methanogenesis: a tribute to Marjory Stephenson:1998 Marjory Stephenson Prize Lecture

The Trimethylamine Methyltransferase Gene and Multiple Dimethylamine Methyltransferase Genes of Methanosarcina barkeri Contain In-Frame and Read-Through Amber Codons

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