Methyltransferases involved in methanol conversion by Methanosarcina barkeri

Meijden, Peter van der; Heythuysen, Henk J.; Pouwels, Aloys; Houwen, Frans P.; Drift, Chris van der; Vogels, Godfried D.

doi:10.1007/bf00407765

Cited by 149 publications

(109 citation statements)

References 23 publications

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“…In acetogenic and methanogenic organisms, association of enzyme components essential for either synthesis of acetate or for the conversion of acetate to methane has been proposed [3,6,11,12]. Hu et al [6] have suggested that the corrinoid and CODH from the acetogen, Clostridium thermoaceticum, may form a complex in vivo.…”

Section: Discussionmentioning

confidence: 99%

“…Hu et al [6] have suggested that the corrinoid and CODH from the acetogen, Clostridium thermoaceticum, may form a complex in vivo. In Methanobacterium barkerii, the efficient transfer of methyl group from methanol to HS-CoM appears to require a multi-enzyme complex [12]. The suggestion that the enzymes of the acetyl-CoA pathway in Clostridium thermoaceticum may assemble in vivo into multienzyme complexes [2] stems from the need to account for the differences in the rate of acetate synthesis attainable in vitro using isolated components as compared to the rate predicted in vivo during fermentation of glucose [3].…”

Section: Discussionmentioning

confidence: 99%

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Identification of a cysteine involved in the interaction between carbon monoxide dehydrogenase and corrinoid/Fe‐S protein from Clostridium thermoaceticum

1993

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In Clostridium thermoaceticum, the synthesis of acetyl-CoA from methyl tetrahydrofolate occurs via a series of enzymatic reactions involving methyl transferase, corrinoid/Fe-S protein (corrinoid), carbon monoxide dehydrogenase (CODH) and ferredoxin. We have investigated the possibility of one or more of these proteins existing as multi-enzyme complexes in vivo with higher catalytic activity. A protein complex consisting of CODH and corrinoid was isolated from the cell-free extracts of Clostridium thermoaceticum. The acetyl-CoA synthesis was found to be -1.8-fold higher with the complex than that observed with the isolated protein components. HPLC gel filtration analyses of the native and DTE reduced complex suggested that the CODH:corrinoid complex is held together primarily by an inter disulfide bond. By differential labeling of thiols with [14C]Nethylmaleimide it was found that Cys-506 of the c~ subunit of CODH was involved in the disulfide linkage with the corrinoid of the complex.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Identification of a cysteine involved in the interaction between carbon monoxide dehydrogenase and corrinoid/Fe‐S protein from Clostridium thermoaceticum

1993

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“…CoM methylation with methanol requires the methyltransferase MtaB and the corrinoid protein MtaC, which is then demethylated by another methylcobamide:CoM methyltransferase, MtaA (13)(14)(15). The methylation of CoM with methylated thiols such as dimethyl sulfide in Methanosarcina barkeri is catalyzed by a corrinoid protein that is methylated by dimethyl sulfide and demethylated by CoM, but in this case an associated CoM methylase carries out both methylation reactions (16).…”

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confidence: 99%

“…For the methanogen methylamine and methanol methyltransferase systems, an activation process is readily detectable in cell extracts that is ATP-and hydrogen-dependent (32,33). Daas et al (34,35) examined the activation of the methanol methyltransferase system in M. barkeri and purified in low yield a methyltransferase activation protein (MAP) which in the presence of a preparation of hydrogenase and uncharacterized proteins was required for ATP-dependent reductive activation of methanol:CoM methyl transfer.…”

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confidence: 99%

RamA, a Protein Required for Reductive Activation of Corrinoid-dependent Methylamine Methyltransferase Reactions in Methanogenic Archaea

Ferguson

Soares

Lienard

et al. 2009

Journal of Biological Chemistry

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Archaeal methane formation from methylamines is initiated by distinct methyltransferases with specificity for monomethylamine, dimethylamine, or trimethylamine. Each methylamine methyltransferase methylates a cognate corrinoid protein, which is subsequently demethylated by a second methyltransferase to form methyl-coenzyme M, the direct methane precursor. Methylation of the corrinoid protein requires reduction of the central cobalt to the highly reducing and nucleophilic Co(I) state. RamA, a 60-kDa monomeric ironsulfur protein, was isolated from Methanosarcina barkeri and is required for in vitro ATP-dependent reductive activation of methylamine:CoM methyl transfer from all three methylamines. In the absence of the methyltransferases, highly purified RamA was shown to mediate the ATP-dependent reductive activation of Co(II) corrinoid to the Co(I) state for the monomethylamine corrinoid protein, MtmC. The ramA gene is located near a cluster of genes required for monomethylamine methyltransferase activity, including MtbA, the methylamine-specific CoM methylase and the pyl operon required for co-translational insertion of pyrrolysine into the active site of methylamine methyltransferases. RamA possesses a C-terminal ferredoxinlike domain capable of binding two tetranuclear iron-sulfur proteins. Mutliple ramA homologs were identified in genomes of methanogenic Archaea, often encoded near methyltrophic methyltransferase genes. RamA homologs are also encoded in a diverse selection of bacterial genomes, often located near genes for corrinoid-dependent methyltransferases. These results suggest that RamA mediates reductive activation of corrinoid proteins and that it is the first functional archetype of COG3894, a family of redox proteins of unknown function.

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“…The central intermediate of methane formation from methanol is 2-(methylthio)ethanesulfonic acid (CH3-S-coenzyme M [CoM]) (19,39,43) which is reductively demrethylated with H2 to yield CH4 and 2-mercaptoethanesulfonic acid (CoM-SH) by the multicomponent methyl-coenzyme M methylreductase system (36, 37). Since the free energy change of this reaction (AG0' = -85 kJ/reaction) is large enough to drive ATP synthesis (9, 19), it has been hypothesized that one or several components of the methylreductase system are membrane associated and involved in proton translocation across the cytoplasmic membrane.…”

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confidence: 99%

Immunocytochemical localization of the coenzyme F420-reducing hydrogenase in Methanosarcina barkeri Fusaro

1991

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The cytological localization of the 8-hydroxy-5-deazaflavin (coenzyme F420)-reducing hydrogenase of Methanosarcina barkenr Fusaro was determined by immunoelectron microscopy, using a specific polyclonal rabbit antiserum raised against the homogeneous deazaflavin-dependent enzyme. In Western blot (immunoblot) experiments this antiserum reacted specifically with the native coenzyme F420-reducing hydrogenase, but did not cross-react with the coenzyme F420-nonreducing hydrogenase activity also detectable in crude extracts prepared from methanol-grown Methanosarcina cells. Immunogold labeling of ultrathin sections of anaerobically fixed methanol-grown cells from the exponential growth phase revealed that the coenzyme F420-reducing hydrogenase was predominantly located in the vicinity of the cytoplasmic membrane. From this result we concluded that the deazaflavin-dependent hydrogenase is associated with the cytoplasmic membrane in intact cells of M. barkeri during growth on methanol as the sole methanogenic substrate, and a possible role of this enzyme in the generation of the electrochemical proton gradient is discussed.During methanogenesis from methanol and H2 by restingcell suspensions of methanol-grown Methanosarcina barkeri, ATP synthesis is stringently coupled to an electrochemical proton gradient and a functional DCCD (N,N'-dicyclohexylcarbodiimide)-sensitive ATP synthase, indicating a chemiosmotic mechanism for energy conservation (8, 10, 11). The central intermediate of methane formation from methanol is 2-(methylthio)ethanesulfonic acid (CH3-S-coenzyme M [CoM]) (19,39,43) which is reductively demrethylated with H2 to yield CH4 and 2-mercaptoethanesulfonic acid (CoM-SH) by the multicomponent methyl-coenzyme M methylreductase system (36, 37). Since the free energy change of this reaction (AG0' = -85 kJ/reaction) is large enough to drive ATP synthesis (9, 19), it has been hypothesized that one or several components of the methylreductase system are membrane associated and involved in proton translocation across the cytoplasmic membrane.It has been demonstrated recently (16,22) that the hydrogen-dependent reductive demethylation of CH3-S-CoM to CH4, a reaction common to all methanogenic bacteria irrespective of their growth substrate (19, 37), proceeds in two steps:CoM-S-S-HTP + H2 -_ CoM-SH + HTP-SH (reaction 2)In the first step (reaction 1) the methylreductase catalyzes the reduction of CH3-S-CoM to CH4 with L-7-mercaptoheptanoylthreonine phosphate (HTP-SH) as the electron donor (29). The heterodisulfide CoM-S-S-HTP formed is then reduced in the second step to CoM-SH and HTP-SH by a hydrogenase-linked heterodisulfide reductase system (reaction 2), and it has been proposed that the reduction of the mixed disulfide rather than methane formation is linked to proton translocation and thus coupled to energy conservation (16, 21).Therefore, we decided to determine the ultrastructural location of the coenzyme F420-reducing hydrogenase (F420-hydrogenase) in M. barkeri by immunoelectron microscopy, using a specific po...

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Methyltransferases involved in methanol conversion by Methanosarcina barkeri

Cited by 149 publications

References 23 publications

Identification of a cysteine involved in the interaction between carbon monoxide dehydrogenase and corrinoid/Fe‐S protein from Clostridium thermoaceticum

Identification of a cysteine involved in the interaction between carbon monoxide dehydrogenase and corrinoid/Fe‐S protein from Clostridium thermoaceticum

RamA, a Protein Required for Reductive Activation of Corrinoid-dependent Methylamine Methyltransferase Reactions in Methanogenic Archaea

Immunocytochemical localization of the coenzyme F420-reducing hydrogenase in Methanosarcina barkeri Fusaro

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