Methanogenic cleavage of acetate by lysates of Methanosarcina barkeri

Baresi, Larry

doi:10.1128/jb.160.1.365-370.1984

Cited by 24 publications

(8 citation statements)

References 32 publications

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“…Hydrogen was required in this soluble system whereas it is not required with a particulate preparation described by Baresi [87]. It has been suggested [84,86] that disruption of the membrane bound electron transport system may lead to the requirement of H2 in the soluble system.…”

Section: Catabolism Of Aceo'l-coa By Methanogensmentioning

confidence: 82%

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The acetyl-CoA pathway of autotrophic growth

Wood

Ragsdale

Pezacka

1986

FEMS Microbiology Letters

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The most direct conceivable route for synthesis of multicarbon compounds from CO: is to join two molecules of CO 2 together to make a 2-carbon compound and then polymerize the 2-carbon compound or add CO 2 successively to the 2-carbon compound to make multicarbon compounds. Recently, it has been demonstrated that the bacterium, Clostridium thermoaceticum, grows autotrophically by such a process. The mechanism involves the reduction of one molecule of CO 2 to a methyl group and then its combination with a second molecule of CO2 and CoA to form acetyl-CoA. We have designated this autotrophic pathway the acetyl-CoA pathway [1]. Evidence is accumulating that this pathway is utilized by other bacteria that grow with CO 2 and H 2 as the source of carbon and energy. This group includes bacteria which, like C. thermoaceticum, produce acetate as a major end product and are called acetogens or acetogenic bacteria. It also includes the methaneproducing bacteria and sulfate-reducing bacteria.The purpose of this review is to examine critically the evidence that the acetyl-CoA pathway occurs in other bacteria by a mechanism that is the same or similar to that found in C. thermoaceticum. For this purpose, the mechanism of the acetyl-CoA pathway, as found in C. thermoaceticum, is described and hypothetical mecha-nims for other organisms are presented based on the acetyl-CoA pathway of C. thermoaceticum. The available data have been reviewed to determine if the hypothetical schemes are in accord with presently known facts. We conclude that the formation of acetyl-CoA by other acetogens, the methanogens and sulphate-reducing bacteria occurs by a mechanism very similar to that of C.therrnoaceticum.

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Section: Catabolism Of Aceo'l-coa By Methanogensmentioning

confidence: 82%

“…They showed that methane and CO 2 originate primarily from the methyl and carboxyl groups of the acetate, respectively [86]. They demonstrated [87] that acetyl phosphate replaces the requirement for both acetate and ATP. With [2-i4C]acetate, H 2 and ATP, 14CHaSCoM was identified as a product.…”

Section: Catabolism Of Aceo'l-coa By Methanogensmentioning

confidence: 99%

The acetyl-CoA pathway of autotrophic growth

Wood

Ragsdale

Pezacka

1986

FEMS Microbiology Letters

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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%

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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“…Recently, 2 such systems have been described. Baresi [298] found that a particulate fraction of Ms. barkeri strain 227 is able to convert acetate into CH 4 under a N 2 atmosphere in the absence of ATP; H 2 inhibited this reaction. Krzycki et al [296,299] described a soluble system, which was operative only in the presence of H 2 and ATP.…”

Section: Ch3coo-+ H + ~ Ch 4 + Comentioning

confidence: 99%

“…A possible role for H 2 may be in reduction of the bound corrinoid involved in -CH 3 group transfer to HS-CoM, analogous to its role in MT 1 activation (sections 6.2 and 6.6). Baresi [298] included dithiothreitol in his assay mixtures and possibly this compound may be used as a reductant instead of H 2 .…”

Section: Ch3coo-+ H + ~ Ch 4 + Comentioning

confidence: 99%

Electron transfer reactions in methanogens

Keltjens

Drift

1986

FEMS Microbiology Letters

112

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Methanogenic bacteria comprise a specialized group of obligately anaerobic microorganisms able to reduce a limited number of substrates to CH4. The intermediates involved in this reduction process remain bound to a series of typical C1‐carriers. Reducing equivalents are either obtained from the oxidation of H2 or from oxidation of carbon substrates to CO2. Electron transfer reactions thus constitute the very essence of the process of methanogenesis. In recent years much progress has been made in the elucidation of the special metabolic pathways and the nature of the C1‐carriers involved in methanogenic bacteria. The energy generated at the oxidoreduction reactions, notably at the methylreductase step, is conserved by ATP synthesis. The energy is used for cell carbon synthesis and, in catalytic amounts, for the reductive activation of some methanogenic enzymes. Before the condensing reaction resulting in the formation of acetyl‐CoA takes place, 2 C1‐units are reduced or oxidized depending on the substrate to a carbonyl and a ‐CH3 group. Formation of the latter proceeds via the methanogenic route. Intermediary cell carbon synthesis starting from acetyl‐CoA involves reductive carboxylations and oxidoreductions by the participation of the enzymes of the tricarboxylic acid cycle.

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Methanogenic cleavage of acetate by lysates of Methanosarcina barkeri

Cited by 24 publications

References 32 publications

The acetyl-CoA pathway of autotrophic growth

The acetyl-CoA pathway of autotrophic growth

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

Electron transfer reactions in methanogens

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