A Methyl Analogue of Cobamide Coenzyme in Relation to Methionine Synthesis by Bacteria

Guest, J. R.; Friedman, Steven G.; Woods, D. D.; Smith, E. Lester

doi:10.1038/195340a0

Cited by 142 publications

(37 citation statements)

References 10 publications

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“…I told him about the requirement of high temperature to catalyze the exchange reactions and that formate was a likely precursor of the methyl group. Stadtman in turn mentioned that methyl-vitamin B 12 could play a role as methyl donor in acetate synthesis, similar to 14 C-methyl-B 12 as substrate in the synthesis of methionine (31). Stadtman and coworkers soon showed it to be the case (63).…”

Section: Total Biosynthesis Of Acetate From Carbon Dioxide By Moorellmentioning

confidence: 99%

A Life with Acetogens, Thermophiles, and Cellulolytic Anaerobes

Ljungdahl

2009

Annu. Rev. Microbiol.

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Frankly, I was surprised to receive an invitation to write a prefatory chapter for the Annual Review of Microbiology. I have read several such chapters written by outstanding researchers, many of whom I know and admire. I did not think I belonged to such a preeminent group. In my view, my contributions to the physiology and biochemistry of anaerobic thermophilic bacteria and, more lately, to anaerobic fungi are modest compared to the contribution made by other authors of prefatory chapters. I am honored to write about my life and my work, and I hope that those who read this chapter will sense how exciting and rewarding they have been.1

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Section: Total Biosynthesis Of Acetate From Carbon Dioxide By Moorellmentioning

confidence: 99%

A Life with Acetogens, Thermophiles, and Cellulolytic Anaerobes

Ljungdahl

2009

Annu. Rev. Microbiol.

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“…thermoautotrophicum have been shown to catalyze the formation of CH,-S-CoM from CH,-Cbl and H-SCoM (Taylor and Wolfe, 1974). Secondly, an enzyme with striking functional similarities to the methanogenic methyltransferase, namely the cobamide-containing methionine synthase of Escherichia coli,has been shown to use CH,-Cbl as an artificial methyl donor for the conversion of homocysteine to methionine (Guest et a]., 1962). Interestingly, the methyl group is transferred from CH,-Cbl to homocysteine without the involvement of the cobamide prosthetic group (reviewed in Taylor, 1982).…”

mentioning

confidence: 99%

The Energetics and Sodium‐Ion Dependence of N⁵‐Methyltetrahydromethanopterin:Coenzyme M Methyltransferase Studied with Cob(I)Alamin as Methyl Acceptor and Methylcob(III)Alamin as Methyl Donor

Weiss

Gärtner

Thauer

1994

European Journal of Biochemistry

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) -EJB 94 132014 W-Methyltetrahydromethanopterin :coenzyme M methyltransferase from methanogenic Archaea is a membrane-associated enzyme complex that uses a methyl-transfer reaction to drive an energyconserving sodium-ion pump. Methyl transfer occurs in two steps, first from N5-methyltetrahydromethanopterin (CH,-H,MPT) to an enzyme-bound cob(1)amide prosthetic group, and secondly from the methylated cobamide to coenzyme M (H-S-CoM). In this study, we report that methyltransferase can also use exogenous cob(1)alamin and methylcob(II1)alamin as methyl acceptor and methyl donor, respectively. The enzyme catalyzes methylcob(II1)alamin formation from CH,-H,MPT and cob(1)alamin (reaction a), and methyl-coenzyme M formation from methylcob(I1I)alamin and H-S-CoM (reaction b). Both reactions were shown to be reversible. Reaction a was catalyzed at approximately the same rate (3 U/mg) and reaction b at approximately 10% the rate (0.3 U/mg) of the physiological reaction, namely methyl transfer from CH,-H,MPT to H-SCoM. The free energy changes (AGO') associated with reactions a and b were both between -10 kJ/ mol and -20 kJ/mol, consistent with a free energy change of approximately -30 kJ/mol determined for the physiological reaction. Reaction b but not reaction a was sodium-ion dependent. Assuming that methylation of exogenous cob(1)alamin and demethylation of exogenous methylcob(II1)alamin mimic methylation and demethylation of the enzyme-bound corrinoid prosthetic group, it can be inferred that methyl transfer from the methylated cobamide prosthetic group to H-S-CoM is a site of coupling with sodium-ion translocation.

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“…How ever, the observation that methylcobalamin can serve as a methyl donor to homocysteine in the biosynthesis of methionine (13), together with the effect of methylcobalamin on methane biosynthesis, suggests that the methyl moiety of the substrate transfers to a cobamide compound, forming a derivative of the me thylcobalamin type followed by a cleavage yielding methane. Several investigators (13,14) have reported that DBCC exogenously added exerts only a little activity on methionine synthetic enzyme system of E. coli. Nevertheless, the possibility can not be excluded that, protein-bound DBCC participates in the methane forma tion systems as shown in Fig.…”

Section: Properties Ofmentioning

confidence: 99%

Chemical Studies on Vitamin B12 and Its Related Compounds

Kato¹

1964

J. Vitaminol

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In the preceding paper (1) the authors found the natural occurrence of a cobamide coenzyme-active substance, probably DBCC2, and several other unidentified vitamin B12-active substances in the cells of thermophilic methane bacteria. This paper is concerned with production of DBCC and the other vitamin B12 analogues from exogenously supplied cyanocobalamin during thermophilic methane fermentation.Under the experimental conditions of this study the yield of DBCC was ap proximately 20°0 of the added cyanocobalamin, being mainly present in the cells. Besides DBCC, orange-red and orange-yellow vitamin B12 group compounds were isolated from both the cells and the supernatant.

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A Methyl Analogue of Cobamide Coenzyme in Relation to Methionine Synthesis by Bacteria

Cited by 142 publications

References 10 publications

A Life with Acetogens, Thermophiles, and Cellulolytic Anaerobes

A Life with Acetogens, Thermophiles, and Cellulolytic Anaerobes

The Energetics and Sodium‐Ion Dependence of N⁵‐Methyltetrahydromethanopterin:Coenzyme M Methyltransferase Studied with Cob(I)Alamin as Methyl Acceptor and Methylcob(III)Alamin as Methyl Donor

Chemical Studies on Vitamin B12 and Its Related Compounds

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A Methyl Analogue of Cobamide Coenzyme in Relation to Methionine Synthesis by Bacteria

Cited by 142 publications

References 10 publications

A Life with Acetogens, Thermophiles, and Cellulolytic Anaerobes

A Life with Acetogens, Thermophiles, and Cellulolytic Anaerobes

The Energetics and Sodium‐Ion Dependence of N5‐Methyltetrahydromethanopterin:Coenzyme M Methyltransferase Studied with Cob(I)Alamin as Methyl Acceptor and Methylcob(III)Alamin as Methyl Donor

Chemical Studies on Vitamin B12 and Its Related Compounds

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The Energetics and Sodium‐Ion Dependence of N⁵‐Methyltetrahydromethanopterin:Coenzyme M Methyltransferase Studied with Cob(I)Alamin as Methyl Acceptor and Methylcob(III)Alamin as Methyl Donor