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Lanz ND, Booker SJ. Auxiliary iron-sulfur cofactors in radical SAM enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1316-34. [PMID: 25597998 DOI: 10.1016/j.bbamcr.2015.01.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 12/15/2014] [Accepted: 01/06/2015] [Indexed: 11/19/2022]
Abstract
A vast number of enzymes are now known to belong to a superfamily known as radical SAM, which all contain a [4Fe-4S] cluster ligated by three cysteine residues. The remaining, unligated, iron ion of the cluster binds in contact with the α-amino and α-carboxylate groups of S-adenosyl-l-methionine (SAM). This binding mode facilitates inner-sphere electron transfer from the reduced form of the cluster into the sulfur atom of SAM, resulting in a reductive cleavage of SAM to methionine and a 5'-deoxyadenosyl radical. The 5'-deoxyadenosyl radical then abstracts a target substrate hydrogen atom, initiating a wide variety of radical-based transformations. A subset of radical SAM enzymes contains one or more additional iron-sulfur clusters that are required for the reactions they catalyze. However, outside of a subset of sulfur insertion reactions, very little is known about the roles of these additional clusters. This review will highlight the most recent advances in the identification and characterization of radical SAM enzymes that harbor auxiliary iron-sulfur clusters. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Nicholas D Lanz
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States
| | - Squire J Booker
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States; Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States.
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Identification of a unique radical S-adenosylmethionine methylase likely involved in methanopterin biosynthesis in Methanocaldococcus jannaschii. J Bacteriol 2014; 196:3315-23. [PMID: 25002541 DOI: 10.1128/jb.01903-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methanopterin (MPT) and its analogs are coenzymes required for methanogenesis and methylotrophy in specialized microorganisms. The methyl groups at C-7 and C-9 of the pterin ring distinguish MPT from all other pterin-containing natural products. However, the enzyme(s) responsible for the addition of these methyl groups has yet to be identified. Here we demonstrate that a putative radical S-adenosyl-L-methionine (SAM) enzyme superfamily member encoded by the MJ0619 gene in the methanogen Methanocaldococcus jannaschii is likely this missing methylase. When MJ0619 was heterologously expressed in Escherichia coli, various methylated pterins were detected, consistent with MJ0619 catalyzing methylation at C-7 and C-9 of 7,8-dihydro-6-hydroxymethylpterin, a common intermediate in both folate and MPT biosynthesis. Site-directed mutagenesis of Cys77 present in the first of two canonical radical SAM CX₃CX₂C motifs present in MJ0619 did not inhibit C-7 methylation, while mutation of Cys102, found in the other radical SAM amino acid motif, resulted in the loss of C-7 methylation, suggesting that the first motif could be involved in C-9 methylation, while the second motif is required for C-7 methylation. Further experiments demonstrated that the C-7 methyl group is not derived from methionine and that methylation does not require cobalamin. When E. coli cells expressing MJ0619 were grown with deuterium-labeled acetate as the sole carbon source, the resulting methyl group on the pterin was predominantly labeled with three deuteriums. Based on these results, we propose that this archaeal radical SAM methylase employs a previously uncharacterized mechanism for methylation, using methylenetetrahydrofolate as a methyl group donor.
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Abstract
Methanogenic archaea of the genus Methanosarcina possess a unique type of metabolism because they use H(2)+CO(2), methylated C(1)-compounds, or acetate as energy and carbon source for growth. The process of methanogenesis is fundamental for the global carbon cycle and represents the terminal step in the anaerobic breakdown of organic matter in freshwater sediments. Moreover, methane is an important greenhouse gas that directly contributes to climate change and global warming. Methanosarcina species convert the aforementioned substrates to CH(4) via the CO(2)-reducing, the methylotrophic, or the aceticlastic pathway. All methanogenic processes finally result in the oxidation of two thiol-containing cofactors (HS-CoM and HS-CoB), leading to the formation of the so-called heterodisulfide (CoM-S-S-CoB) that contains an intermolecular disulfide bridge. This molecule functions as the terminal electron acceptor of a branched respiratory chain. Molecular hydrogen, reduced coenzyme F(420), or reduced ferredoxin are used as electron donors. The key enzymes of the respiratory chain (Ech hydrogenase, F(420)-nonreducing hydrogenase, F(420)H(2) dehydrogenase, and heterodisulfide reductase) couple the redox reactions to proton translocation across the cytoplasmic membrane. The resulting electrochemical proton gradient is the driving force for ATP synthesis. Here, we describe the methods and techniques of how to analyze electron transfer reactions, the process of proton translocation, and the formation of ATP.
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Affiliation(s)
- Cornelia Welte
- Institute of Microbiology and Biotechnology, University of Bonn, Bonn, Germany
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Fischer R, Thauer RK. Ferredoxin-dependent methane formation from acetate in cell extracts ofMethanosarcina barkeri(strain MS). FEBS Lett 2001; 269:368-72. [PMID: 15452975 DOI: 10.1016/0014-5793(90)81195-t] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cell extracts of Methanosarcina barkeri grown on acetate catalyzed the conversion of acetyl-CoA to CO2 and CH4 at a specific rate of 50 nmol min-1 mg-1. When ferredoxin was removed from the extracts by DEAE-Sephacel anion exchange chromatography, the extracts were inactive but full activity was restored upon addition of purified ferredoxin from M. barkeri or from Clostridium pasteurianum. The apparent Km for ferredoxin from M. barkeri was determined to be 2.5 M. A ferredoxin dependence was also found for the formation of CO2, H2 and methylcoenzyme M from acetyl-CoA, when methane formation was inhibited by bromoethanesulfonate. Reduction of methyl-coenzyme M with H2 did not require ferredoxin. These and other data indicate that ferredoxin is involved as electron carrier in methanogenesis from acetate. Methanogenesis from acetyl-CoA in cell extracts was not dependent on the membrane fraction, which contains the cytochromes.
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Affiliation(s)
- R Fischer
- Laboratorium für Mikrobiologie, Fachbereich Biologie, Philipps-Universität, Karl-von-Frisch-Strasse, D-3550 Marburg, FRG
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6
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Abstract
In the late 1970s, on the basis of rRNA phylogeny, Archaea (archaebacteria) was identified as a distinct domain of life besides Bacteria (eubacteria) and Eucarya. Though forming a separate domain, Archaea display an enormous diversity of lifestyles and metabolic capabilities. Many archaeal species are adapted to extreme environments with respect to salinity, temperatures around the boiling point of water, and/or extremely alkaline or acidic pH. This has posed the challenge of studying the molecular and mechanistic bases on which these organisms can cope with such adverse conditions. This review considers our cumulative knowledge on archaeal mechanisms of primary energy conservation, in relationship to those of bacteria and eucarya. Although the universal principle of chemiosmotic energy conservation also holds for Archaea, distinct features have been discovered with respect to novel ion-transducing, membrane-residing protein complexes and the use of novel cofactors in bioenergetics of methanogenesis. From aerobically respiring Archaea, unusual electron-transporting supercomplexes could be isolated and functionally resolved, and a proposal on the organization of archaeal electron transport chains has been presented. The unique functions of archaeal rhodopsins as sensory systems and as proton or chloride pumps have been elucidated on the basis of recent structural information on the atomic scale. Whereas components of methanogenesis and of phototrophic energy transduction in halobacteria appear to be unique to Archaea, respiratory complexes and the ATP synthase exhibit some chimeric features with respect to their evolutionary origin. Nevertheless, archaeal ATP synthases are to be considered distinct members of this family of secondary energy transducers. A major challenge to future investigations is the development of archaeal genetic transformation systems, in order to gain access to the regulation of bioenergetic systems and to overproducers of archaeal membrane proteins as a prerequisite for their crystallization.
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Affiliation(s)
- G Schäfer
- Institut für Biochemie, Medizinische Universität zu Lübeck, Lübeck, Germany.
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Thauer RK. Biochemistry of methanogenesis: a tribute to Marjory Stephenson. 1998 Marjory Stephenson Prize Lecture. MICROBIOLOGY (READING, ENGLAND) 1998; 144 ( Pt 9):2377-2406. [PMID: 9782487 DOI: 10.1099/00221287-144-9-2377] [Citation(s) in RCA: 628] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch-Straße, D-35043 Marburg, and Laboratorium für Mikrobiologie, Fachbereich Biologie, Philipps-Universität, Karl-von-Frisch-Straße, D-35032 Marburg, GermanyIn 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.
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Affiliation(s)
- Rudolf K Thauer
- (Delivered at the 140th Ordinary Meeting of the Society for General Microbiology, 31 March 1998)
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Harms U, Thauer RK. Methylcobalamin: coenzyme M methyltransferase isoenzymes MtaA and MtbA from Methanosarcina barkeri. Cloning, sequencing and differential transcription of the encoding genes, and functional overexpression of the mtaA gene in Escherichia coli. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 235:653-9. [PMID: 8654414 DOI: 10.1111/j.1432-1033.1996.00653.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Methanosarcina barkeri is known to contain two methyltransferase isoenzymes, here designated MtaA and MtbA, which catalyze the formation of methyl-coenzyme M from methylcobalamin and coenzyme M. The genes encoding the two soluble 34-kDa proteins have been cloned and sequenced. mtaA and mtbA wee found to be located in different parts of the genome, each forming a monocystronic transcription unit. Northern blot analysis revealed that mtaA is preferentially transcribed when M. barkeri is grown on methanol and the mtbA gene when the organism is grown on H2/CO2 or trimethylamine. Comparison of the deduced amino acid sequences revealed the sequences of the two isoenzymes to be 37% identical. Both isoenzymes showed sequence similarity to uroporphyrinogen III decarboxylase from Escherichia coli. The mtaA gene was tagged with a sequence encoding six His placed bp before the mtaA start codon, and was functionally overexpressed in E. coli. 25% of the E. coli protein was found to be active methyltransferase which could be purified in two steps to apparent homogeneity with a 70% yield.
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Affiliation(s)
- U Harms
- Max-Planck-Institut für terrestrische Mikrobiologie und Laboratorium für Mikrobiologie des Fachbereichs Biologie der Philipps-Universität, Marburg, Germany
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Gärtner P, Weiss DS, Harms U, Thauer RK. N5-methyltetrahydromethanopterin:coenzyme M methyltransferase from Methanobacterium thermoautotrophicum. Catalytic mechanism and sodium ion dependence. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 226:465-72. [PMID: 8001564 DOI: 10.1111/j.1432-1033.1994.tb20071.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
N5-Methyltetrahydromethanopterin:coenzyme M methyltransferase from methanogenic Archaea is a membrane associated, corrinoid-containing enzyme complex which uses a methyl-transfer reaction to drive an energy-conserving sodium ion pump. The purified methyltransferase from Methanobacterium thermoautotrophicum (strain Marburg) exhibited a rhombic EPR signal indicative of a base-on cob(II)amide. In this form, the enzyme was almost completely inactive. Upon addition of Ti(III)citrate, which is a one-electron reductant known to reduce corrinoids to the cob(I)amide form, the EPR signal was completely quenched. In the reduced form, the enzyme was active. When the purified complex was incubated in the presence of both Ti(III) and N5-methyltetrahydromethanopterin (CH3-H4MPT), enzyme-bound Co-methyl-5'-hydroxybenzimidazolyl cob(III)amide was formed. Upon incubation of the methylated enzyme with either tetrahydromethanopterin or coenzyme M, the enzyme was demethylated with the concomitant formation of CH3-H4MPT and methylcoenzyme M, respectively. Enzyme demethylation, in contrast to enzyme methylation, was not dependent on the presence of Ti(III). Methyl transfer from the methylated enzyme to coenzyme M was essentially irreversible. These results are interpreted to that the purified enzyme complex is active only when the enzyme-bound corrinoid is in the reduced cob(I)amide form, and that methyl transfer from CH3-H4MPT to coenzyme M proceeds via nucleophilic attack of the cobalt(I) on the N5-methyl substituent of CH3-H4MPT, forming an enzyme-bound CH3-corrinoid as intermediate. Methyl-coenzyme M formation from CH3-H4MPT and coenzyme M, as catalyzed by the purified methyltransferase, was stimulated by sodium ions, half-maximal activity being obtained at approximately 50 microM Na+. We therefore infer that the methyltransferase, as isolated, is capable of vectorial sodium ion translocation.
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Affiliation(s)
- P Gärtner
- Max-Planck-Institut für terrestrische Mikrobiologie, Philipps-Universität, Marburg, Germany
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Peer CW, Painter MH, Rasche ME, Ferry JG. Characterization of a CO: heterodisulfide oxidoreductase system from acetate-grown Methanosarcina thermophila. J Bacteriol 1994; 176:6974-9. [PMID: 7961460 PMCID: PMC197069 DOI: 10.1128/jb.176.22.6974-6979.1994] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
During the methanogenic fermentation of acetate by Methanosarcina thermophila, the CO dehydrogenase complex cleaves acetyl coenzyme A and oxidizes the carbonyl group (or CO) to CO2, followed by electron transfer to coenzyme M (CoM)-S-S-coenzyme B (CoB) and reduction of this heterodisulfide to HS-CoM and HS-CoB (A. P. Clements, R. H. White, and J. G. Ferry, Arch. Microbiol. 159:296-300, 1993). The majority of heterodisulfide reductase activity was present in the soluble protein fraction after French pressure cell lysis. A CO:CoM-S-S-CoB oxidoreductase system from acetate-grown cells was reconstituted with purified CO dehydrogenase enzyme complex, ferredoxin, membranes, and partially purified heterodisulfide reductase. Coenzyme F420 (F420) was not required, and CO:F420 oxidoreductase activity was not detected in cell extracts. The membranes contained cytochrome b that was reduced with CO and oxidized with CoM-S-S-CoB. The results suggest that a novel CoM-S-S-CoB reducing system operates during acetate conversion to CH4 and CO2. In this system, ferredoxin transfers electrons from the CO dehydrogenase complex to membrane-bound electron carriers, including cytochrome b, that are required for electron transfer to the heterodisulfide reductase. The cytochrome b was purified from solubilized membrane proteins in a complex with six other polypeptides. The cytochrome was not reduced when the complex was incubated with H2 or CO, and H2 uptake hydrogenase activity was not detected; however, the addition of CO dehydrogenase enzyme complex and ferredoxin enabled the CO-dependent reduction of cytochrome b.
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Affiliation(s)
- C W Peer
- Department of Biochemistry and Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0305
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Abstract
Methanogenic archaea convert a few simple compounds such as H2 + CO2, formate, methanol, methylamines, and acetate to methane. Methanogenesis from all these substrates requires a number of unique coenzymes, some of which are exclusively found in methanogens. H2-dependent CO2 reduction proceeds via carrier-bound C1 intermediates which become stepwise reduced to methane. Methane formation from methanol and methylamines involves the disproportionation of the methyl groups. Part of the methyl groups are oxidized to CO2, and the reducing equivalents thereby gained are subsequently used to reduce other methyl groups to methane. This process involves the same C1 intermediates that are formed during methanogenesis from CO2. Conversion of acetate to methane and carbon dioxide is preceded by its activation to acetyl-CoA. Cleavage of the latter compound yields a coenzyme-bound methyl moiety and an enzyme-bound carbonyl group. The reducing equivalents gained by oxidation of the carbonyl group to carbon dioxide are subsequently used to reduce the methyl moiety to methane. All these processes lead to the generation of transmembrane ion gradients which fuel ATP synthesis via one or two types of ATP synthases. The synthesis of cellular building blocks starts with the central anabolic intermediate acetyl-CoA which, in autotrophic methanogens, is synthesized from two molecules of CO2 in a linear pathway.
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Affiliation(s)
- M Blaut
- Institut für Mikrobiologie, Universität Göttingen, Germany
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Kemner JM, Zeikus JG. Purification and characterization of membrane-bound hydrogenase from Methanosarcina barkeri MS. Arch Microbiol 1994. [DOI: 10.1007/bf00248892] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
Eleven adenosylcorrinoid-dependent rearrangements and elimination reactions have been described during the last four decades of vitamin B12 research. In contrast, only the cobamide-dependent methionine synthase was well established as a corrinoid-dependent methyl transfer reaction. yet, investigations during the last few years revealed nine additional corrinoid-dependent methyltransferases. Many of these reactions are catalyzed by bacteria which possess a distinct C1 metabolism. Notably acetogenic and methanogenic bacteria carry out such methyl transfers in their anabolism and catabolism. Tetrahydrofolate or a similar pterine derivative is a key intermediate in these reactions. It functions as methyl acceptor and the methylated tetrahydrofolate serves as a methyl donor.
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Affiliation(s)
- E Stupperich
- Department of Applied Microbiology, University of Ulm, FRG
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Yeliseev A, Gärtner P, Harms U, Linder D, Thauer RK. Function of methylcobalamin: coenzyme M methyltransferase isoenzyme II in Methanosarcina barkeri. Arch Microbiol 1993; 159:530-6. [PMID: 8352643 DOI: 10.1007/bf00249031] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Methanosarcina barkeri was recently shown to contain two cytoplasmic isoenzymes of methylcobalamin: coenzyme M methyltransferase (methyltransferase 2). Isoenzyme I predominated in methanol-grown cells and isoenzyme II in acetate-grown cells. It was therefore suggested that isoenzyme I functions in methanogenesis from methanol and isoenzyme II in methanogenesis from acetate. We report here that cells of M. barkeri grown on trimethylamine, H2/CO2, or acetate contain mainly isoenzyme II. These cells were found to have in common that they can catalyze the formation of methane from trimethylamine and H2, whereas only acetate-grown cells can mediate the formation of methane from acetate. Methanol-grown cells, which contained only low concentrations of isoenzyme II, were unable to mediate the formation of methane from both trimethylamine and acetate. These and other results suggest that isoenzyme II (i) is employed for methane formation from trimethylamine rather than from acetate, (ii) is constitutively expressed rather than trimethylamine-induced, and (iii) is repressed by methanol. The constitutive expression of isoenzyme II in acetate-grown M. barkeri can explain its presence in these cells. The N-terminal amino acid sequences of isoenzyme I and isoenzyme II were analyzed and found to be only 55% similar.
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Affiliation(s)
- A Yeliseev
- Laboratorium für Mikrobiologie des Fachbereichs Biologie der Philipps-Universität Marburg, Germany
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Gärtner P, Ecker A, Fischer R, Linder D, Fuchs G, Thauer RK. Purification and properties of N5-methyltetrahydromethanopterin:coenzyme M methyltransferase from Methanobacterium thermoautotrophicum. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 213:537-45. [PMID: 8477726 DOI: 10.1111/j.1432-1033.1993.tb17792.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
N5-Methyltetrahydromethanopterin:coenzyme M meth-yltransferase is an integral membrane protein found in methanogenic archaea. It catalyzes an energy-conserving step in methane formation from CO2 and from acetate. The enzyme from Methanobacterium thermoautotrophicum (strain Marburg) has been purified 30-fold to apparent homogeneity. The purified enzyme had an apparent molecular mass of 670 kDa and was composed of seven different polypeptides of 34 kDa, 28 kDa, 24 kDa, 23 kDa, 21 kDa, 13 kDa, and 12 kDa. The N-terminal amino acid sequences of these polypeptides were determined. The native 670-kDa enzyme was found to contain 7.6 mol 5-hydroxybenzimidazolyl cobamide/mol, 37 mol non-heme iron/mol and 34 mol acid-labile sulfur/mol. Cobalt analyses after sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed that the corrinoid was bound to the 23-kDa polypeptide. The apparent molecular masses of the polypeptides given above were determined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis without boiling the samples prior to analysis. When the samples were boiled, as is usually done, the 23-kDa polypeptide changed its apparent molecular mass to 33 kDa and the 21-kDa, 24-kDa, and 28-kDa polypeptides formed aggregates. The specific activity (apparent Vmax) of the purified methyltransferase preparation was 11.6 mumol.min-1.mg protein-1. The apparent Km for N5-methyltetrahydromethanopterin was 260 microM and that for coenzyme M was 60 microM. The preparation was absolutely dependent on the presence of Ti(III) for activity. ATP enhanced the activity 1.5-2-fold.
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Affiliation(s)
- P Gärtner
- Laboratorium für Mikrobiologie des Fachbereichs Biologie, Philipps-Universität Marburg, Germany
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Mukhopadhyay B, Purwantini E, Daniels L. Effect of methanogenic substrates on coenzyme F420-dependent N5,N10-methylene-H4MPT dehydrogenase, N5,N10-methenyl-H4MPT cyclohydrolase and F420-reducing hydrogenase activities in Methanosarcina barkeri. Arch Microbiol 1993. [DOI: 10.1007/bf00250274] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chapter 4 Bioenergetics and transport in methanogens and related thermophilic archaea. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s0167-7306(08)60253-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Jablonski P, Lu W, Ragsdale S, Ferry J. Characterization of the metal centers of the corrinoid/iron-sulfur component of the CO dehydrogenase enzyme complex from Methanosarcina thermophila by EPR spectroscopy and spectroelectrochemistry. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)54153-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Blaut M, Müller V, Gottschalk G. Energetics of methanogenesis studied in vesicular systems. J Bioenerg Biomembr 1992; 24:529-46. [PMID: 1459985 DOI: 10.1007/bf00762346] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Methanogenesis is restricted to a group of prokaryotic microorganisms which thrive in strictly anaerobic habitats where they play an indispensable role in the anaerobic food chain. Methanogenic bacteria possess a number of unique cofactors and coenzymes that play an important role in their specialized metabolism. Methanogenesis from a number of simple substrates such as H2 + CO2, formate, methanol, methylamines, and acetate is associated with the generation of transmembrane electrochemical gradients of protons and sodium ions which serve as driving force for a number of processes such as the synthesis of ATP via an ATP synthase, reverse electron transfer, and solute uptake. Several unique reactions of the methanogenic pathways have been identified that are involved in energy transduction. Their role and importance for the methanogenic metabolism are described.
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Affiliation(s)
- M Blaut
- Institut für Mikrobiologie, Georg-August-Universität Göttingen, Germany
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Abstract
The general features are known for the pathway by which most methane is produced in nature. All acetate-utilizing methanogenic microorganisms contain CODH which catalyzes the cleavage of acetyl-CoA; however, the pathway differs from all other acetate-utilizing anaerobes in that the methyl group is reduced to methane with electrons derived from oxidation of the carbonyl group of acetyl-CoA to CO2. The current understanding of the methanogenic fermentation of acetate provides impressions of nature's novel solutions to problems of methyl transfer, electron transport, and energy conservation. The pathway is now at a level of understanding that will permit productive investigations of these and other interesting questions in the near future.
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Affiliation(s)
- J G Ferry
- Department of Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0305
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Fischer R, Gärtner P, Yeliseev A, Thauer RK. N5-methyltetrahydromethanopterin: coenzyme M methyltransferase in methanogenic archaebacteria is a membrane protein. Arch Microbiol 1992; 158:208-17. [PMID: 1444718 DOI: 10.1007/bf00290817] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An assay is described that allows the direct measurement of the enzyme activity catalyzing the transfer of the methyl group from N5-methyltetrahydromethanopterin (CH3-H4MPT) to coenzyme M (H-S-CoM) in methanogenic archaebacteria. With this method the topology, the partial purification, and the catalytic properties of the methyltransferase in methanol- and acetate-grown Methanosarcina barkeri and in H2/CO(2)-grown Methanobacterium thermoautotrophicum were studied. The enzyme activity was found to be associated almost completely with the membrane fraction and to require detergents for solubilization. The transferase activity in methanol-grown M. barkeri was studied in detail. The membrane fraction exhibited a specific activity of CH3-S-CoM formation from CH3-H4MPT (apparent Km = 50 microM) and H-S-CoM (apparent Km = 250 microM) of approximately 0.6 mumol.min-1.mg protein-1. For activity the presence of Ti(III) citrate (apparent Km = 15 microM) and of ATP (apparent Km = 30 microM) were required in catalytic amounts. Ti(III) could be substituted by reduced ferredoxin. ATP could not be substituted by AMP, CTP, GTP, S-adenosylmethionine, or by ATP analogues. The membrane fraction was methylated by CH3-H4MPT in the absence of H-S-CoM. This methylation was dependent on Ti(III) and ATP. The methylated membrane fraction catalyzed the methyltransfer from CH3-H4MPT to H-S-CoM in the absence of ATP and Ti(III). Demethylation in the presence of H-S-CoM also did not require Ti(III) or ATP. Based on these findings a mechanism for the methyltransfer reaction and for the activation of the enzyme is proposed.
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Affiliation(s)
- R Fischer
- Laboratorium für Mikrobiologie des Fachbereichs Biologie, Philipps-Universität Marburg, Federal Republic of Germany
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Kamlage B, Blaut M. Characterization of cytochromes from Methanosarcina strain Göl and their involvement in electron transport during growth on methanol. J Bacteriol 1992; 174:3921-7. [PMID: 1597414 PMCID: PMC206100 DOI: 10.1128/jb.174.12.3921-3927.1992] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Methanosarcina strain Gö1 was tested for the presence of cytochromes. Low-temperature spectroscopy, hemochrome derivative spectroscopy, and redox titration revealed the presence of two b-type (b559 and b564) and two c-type (c547 and c552) cytochromes in membranes from Methanosarcina strain Gö1. The midpoint potentials determined were Em,7 = -135 +/- 5 and -240 +/- 11 mV (b-type cytochromes) and Em,7 = -140 +/- 10 and -230 +/- 10 mV (c-type cytochromes). The protoheme IX and the heme c contents were 0.21 to 0.24 and 0.09 to 0.28 mumol/g of membrane protein, respectively. No cytochromes were detectable in the cytoplasmic fraction. Of various electron donors and acceptors tested, only the reduced form of coenzyme F420 (coenzyme F420H2) and the heterodisulfide of coenzyme M and 7-mercaptoheptanoylthreonine phosphate (CoM-S-S-HTP) were capable of reducing and oxidizing the cytochromes at a high rate, respectively. Addition of CoM-S-S-HTP to reduced cytochromes and subsequent low-temperature spectroscopy revealed the oxidation of cytochrome b564. On the basis of these results, we suggest that one or several cytochromes participate in the coenzyme F420H2-dependent reduction of the heterodisulfide.
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Affiliation(s)
- B Kamlage
- Institut für Mikrobiologie, Georg-August-Universität Göttingen, Germany
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26
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Jetten MS, Stams AJ, Zehnder AJ. Methanogenesis from acetate: a comparison of the acetate metabolism inMethanothrix soehngeniiandMethanosarcinaspp. FEMS Microbiol Lett 1992. [DOI: 10.1111/j.1574-6968.1992.tb04987.x] [Citation(s) in RCA: 342] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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27
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Abstract
Methane is a product of the energy-yielding pathways of the largest and most phylogenetically diverse group in the Archaea. These organisms have evolved three pathways that entail a novel and remarkable biochemistry. All of the pathways have in common a reduction of the methyl group of methyl-coenzyme M (CH3-S-CoM) to CH4. Seminal studies on the CO2-reduction pathway have revealed new cofactors and enzymes that catalyze the reduction of CO2 to the methyl level (CH3-S-CoM) with electrons from H2 or formate. Most of the methane produced in nature originates from the methyl group of acetate. CO dehydrogenase is a key enzyme catalyzing the decarbonylation of acetyl-CoA; the resulting methyl group is transferred to CH3-S-CoM, followed by reduction to methane using electrons derived from oxidation of the carbonyl group to CO2 by the CO dehydrogenase. Some organisms transfer the methyl group of methanol and methylamines to CH3-S-CoM; electrons for reduction of CH3-S-CoM to CH4 are provided by the oxidation of methyl groups to CO2.
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Affiliation(s)
- J G Ferry
- Department of Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0305
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28
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Grahame D. Catalysis of acetyl-CoA cleavage and tetrahydrosarcinapterin methylation by a carbon monoxide dehydrogenase-corrinoid enzyme complex. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54558-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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29
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Cao XJ, Krzycki JA. Acetate-dependent methylation of two corrinoid proteins in extracts of Methanosarcina barkeri. J Bacteriol 1991; 173:5439-48. [PMID: 1885523 PMCID: PMC208256 DOI: 10.1128/jb.173.17.5439-5448.1991] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Corrinoid proteins have been implicated as methyl carriers in methane formation from acetate, yet specific corrinoid proteins methylated by acetate-derived intermediates have not been identified. In the presence of ATP, H2, and bromoethanesulfonic acid, label from 3H- or 2-14C-labeled acetate was incorporated into the protein fraction of cell extracts of Methanosarcina barkeri. Incorporated label was susceptible to photolysis, yielding labeled methane as the anaerobic photolysis product. Size exclusion high-pressure liquid chromatography (HPLC) demonstrated the presence of at least three labeled proteins with native molecular sizes of 480, 200, and 29 kDa, while electrophoresis indicated that four major labeled proteins were present. Dual-label experiments demonstrated that these four proteins were methylated rather than acetylated. Two of the proteins (480 and 29 kDa) contained the majority of radiolabel and were stably methylated. After labeling with [2-14C]acetate, the stable 14CH3-proteins were partially purified, and 14CH3-cofactors were isolated from each protein. UV-visible spectroscopy and HPLC demonstrated these to be methylated corrinoids. When the 480-kDa corrinoid protein was purified to 70% homogeneity, the preparation was found to have subunits of 40 and 30 kDa. The 480-kDa protein but not the 29-kDa protein was methylated during in vitro methanogenesis from acetate and demethylated as methanogenesis ceased, consistent with the involvement of this protein in methane formation.
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Affiliation(s)
- X J Cao
- Department of Microbiology, Ohio State University, Columbus 43210
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30
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Coenzyme F420 dependent N5, N10-methylenetetrahydromethanopterin dehydrogenase in methanol grown Methanosarcina barkeri. Arch Microbiol 1991. [DOI: 10.1007/bf00244966] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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31
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Jablonski PE, Ferry JG. Purification and properties of methyl coenzyme M methylreductase from acetate-grown Methanosarcina thermophila. J Bacteriol 1991; 173:2481-7. [PMID: 2013570 PMCID: PMC207811 DOI: 10.1128/jb.173.8.2481-2487.1991] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Methyl coenzyme M methylreductase from acetate-grown Methanosarcina thermophila TM-1 was purified 16-fold from a cell extract to apparent homogeneity as determined by native polyacrylamide gel electrophoresis. Ninety-four percent of the methylreductase activity was recovered in the soluble fraction of cell extracts. The estimated native molecular weight of the enzyme was between 132,000 (standard deviation [SD], 1,200) and 141,000 (SD, 1,200). Denaturing polyacrylamide gel electrophoresis revealed three protein bands corresponding to molecular weights of 69,000 (SD, 1,200), 42,000 (SD, 1,200), and 33,000 (SD, 1,200) and indicated a subunit configuration of alpha 1 beta 1 gamma 1. As isolated, the enzyme was inactive but could be reductively reactivated with titanium (III) citrate or reduced ferredoxin. ATP stimulated enzyme reactivation and was postulated to be involved in a conformational change of the inactive enzyme from an unready state to a ready state that could be reductively reactivated. The temperature and pH optima for enzyme activity were 60 degrees C and between 6.5 and 7.0, respectively. The active enzyme contained 1 mol of coenzyme F430 per mol of enzyme (Mr, 144,000). The Kms for 2-(methylthio)ethane-sulfonate and 7-mercaptoheptanoylthreonine phosphate were 3.3 mM and 59 microM, respectively.
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Affiliation(s)
- P E Jablonski
- Department of Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0305
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32
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Activities of formylmethanofuran dehydrogenase, methylenetetrahydromethanopterin dehydrogenase, methylenetetrahydromethanopterin reductase, and heterodisulfide reductase in methanogenic bacteria. Arch Microbiol 1991. [DOI: 10.1007/bf00244962] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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33
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Abstract
We know of three routes that organisms have evolved to synthesize complex organic molecules from CO2: the Calvin cycle, the reverse tricarboxylic acid cycle, and the reductive acetyl-CoA pathway. This review describes the enzymatic steps involved in the acetyl-CoA pathway, also called the Wood pathway, which is the major mechanism of CO2 fixation under anaerobic conditions. The acetyl-CoA pathway is also able to form acetyl-CoA from carbon monoxide. There are two parts to the acetyl-CoA pathway: (1) reduction of CO2 to methyltetrahydrofolate (methyl-H4folate) and (2) synthesis of acetyl-CoA from methyl-H4folate, a carboxyl donor such as CO or CO2, and CoA. This pathway is unique in that the major intermediates are enzyme-bound and are often organometallic complexes. Our current understanding of the pathway is based on radioactive and stable isotope tracer studies, purification of the component enzymes (some extremely oxygen sensitive), and identification of the enzyme-bound intermediates by chromatographic, spectroscopic, and electrochemical techniques. This review describes the remarkable series of enzymatic steps involved in acetyl-CoA formation by this pathway that is a key component of the global carbon cycle.
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Affiliation(s)
- S W Ragsdale
- Department of Chemistry, University of Wisconsin-Milwaukee
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34
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Karrasch M, Börner G, Enssle M, Thauer RK. The molybdoenzyme formylmethanofuran dehydrogenase from Methanosarcina barkeri contains a pterin cofactor. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 194:367-72. [PMID: 2125267 DOI: 10.1111/j.1432-1033.1990.tb15627.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Recently formylmethanofuran dehydrogenase from the archaebacterium Methanosarcina barkeri has been shown to be a novel molybdo-iron-sulfur protein. We report here that the enzyme contains one mol of a bound pterin cofactor/mol molybdenum, similar but not identical to the molybdopterin of milk xanthine oxidase. The two pterins, after oxidation with I2 at pH 2.5, showed identical fluorescence spectra and, after oxidation with permanganate at pH 13, yielded pterin 6-carboxylic acid. They differed, however, in their apparent molecular mass: the pterin of formylmethanofuran dehydrogenase was 400 Da larger than that of milk xanthine oxidase, a property also exhibited by the pterin cofactor of eubacterial molybdoenzymes. A homogeneous formylmethanofuran dehydrogenase preparation was used for these investigations. The enzyme, with a molecular mass of 220 kDa, contained 0.5-0.8 mol molybdenum, 0.6-0.9 mol pterin, 28 +/- 2 mol non-heme iron and 28 +/- 2 mol acid-labile sulfur/mol based on a protein determination with bicinchoninic acid. The specific activity was 175 mumol.min-1.mg-1 (kcat = 640 s-1) assayed with methylviologen (app. Km = 0.02 mM) as artificial electron acceptor. The apparent Km for formylmethanofuran was 0.02 mM.
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Affiliation(s)
- M Karrasch
- Laboratorium für Mikrobiologie, Philipps-Universität Marburg, FRG
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Keltjens JT, Brömmelstroet BW, Kengen S, Drift C, Vogels GD. 5,6,7,8-Tetrahydromethanopterin-dependent enzymes involved in methanogenesis. FEMS Microbiol Lett 1990. [DOI: 10.1111/j.1574-6968.1990.tb04932.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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36
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Ma K, Thauer RK. Purification and properties of N5, N10-methylenetetrahydromethanopterin reductase from Methanobacterium thermoautotrophicum (strain Marburg). EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 191:187-93. [PMID: 2379499 DOI: 10.1111/j.1432-1033.1990.tb19109.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The reduction of N5,N10-methylenetrahydromethanopterin (CH2 = H4MPT) to N5-methyltetrahydromethanopterin (CH3-H4MPT) is an intermediate step in methanogenesis from CO2 and H2. The reaction is catalyzed by CH2 = H4MPT reductase. The enzyme from Methanobacterium thermoautotrophicum (strain Marburg) was found to be specific for reduced coenzyme F420 as electron donor; neither NADH or NADPH nor reduced viologen dyes could substitute for the reduced 5-deazaflavin. The reductase was purified over 100-fold to apparent homogeneity. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed only one protein band at the 36-kDa position. The apparent molecular mass of the native enzyme was determined by gel filtration to be in the order of 150 kDa. The purified enzyme was colourless. It did not contain flavin or iron. The ultraviolet visible spectrum was almost identical to that of albumin, suggesting the absence of a chromophoric prosthetic group. Reciprocal plots of the enzyme activity versus the substrate concentration at different constant concentrations of the second substrate yielded straight lines intersecting at one point on the abscissa to the left of the vertical axis. This intersecting pattern is characteristic of a ternary complex catalytic mechanism. The Km for CH2 = H4MPT and for the reduced coenzyme F420 were determined to be 0.3 mM and 3 microM, respectively. Vmax was 6000 mumol.min-1.mg protein-1 (kcat = 3600 s-1). The CH2 = H4MPT reductase was stable in the presence of air; at 4 C less than 10% activity was lost within 24 h.
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Affiliation(s)
- K Ma
- Laboratorium für Mikrobiologie, Fachbereich Biologie, Philipps-Universität, Marburg, Federal Republic of Germany
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37
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38
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M�ller-Zinkhan D, Thauer RK. Anaerobic lactate oxidation to 3 CO2 by Archaeoglobus fulgidus via the carbon monoxide dehydrogenase pathway: demonstration of the acetyl-CoA carbon-carbon cleavage reaction in cell extracts. Arch Microbiol 1990. [DOI: 10.1007/bf00249070] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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39
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Methanogenesis from acetate in cell extracts of Methanosarcina barkeri: Isotope exchange between CO2 and the carbonyl group of acetyl-CoA, and the role of H2. Arch Microbiol 1990. [DOI: 10.1007/bf00247814] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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40
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Jetten MS, Stams AJ, Zehnder AJ. Purification and some properties of the methyl-CoM reductase ofMethanothrix soehngenii. FEMS Microbiol Lett 1990. [DOI: 10.1111/j.1574-6968.1990.tb03993.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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41
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Kaesler B, Schönheit P. The sodium cycle in methanogenesis. CO2 reduction to the formaldehyde level in methanogenic bacteria is driven by a primary electrochemical potential of Na+ generated by formaldehyde reduction to CH4. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 186:309-16. [PMID: 2557210 DOI: 10.1111/j.1432-1033.1989.tb15210.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
CH4 formation from CO2 and H2 rather than from formaldehyde and H2 in methanogenic bacteria is inhibited by uncouplers, indicating that CO2 reduction to the formaldehyde level is energy-driven. We report here that in Methanosarcina barkeri the driving force is a primary electrochemical sodium potential (delta mu Na+) generated by formaldehyde reduction to CH4. This is concluded from the following findings. 1. CO2 reduction to CH4 was insensitive towards protonophores, when the Na+/H+ antiporter was inhibited; under these conditions delta mu Na+ was 120 mV (inside negative), whereas both delta mu H+ and the cellular ATP content were low. 2. CO2 reduction to CH4, rather than formaldehyde reduction, was sensitive towards Na+ ionophores, which dissipated delta mu Na+. 3. CO2 reduction to CH4, in the presence of protonophores and Na+/H+ antiport inhibitors, was coupled with the extrusion of 1-2 mol Na+/mol CH4, and formaldehyde reduction to CH4 was coupled with the extrusion of 3-4 mol Na+/mol CH4. Thus during CO2 reduction to the formaldehyde level 2-3 mol Na+ were consumed.
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Affiliation(s)
- B Kaesler
- Fachbereich Biologie-Mikrobiologie, Philipps-Universität Marburg, FRG
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42
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Kaesler B, Schönheit P. The role of sodium ions in methanogenesis. Formaldehyde oxidation to CO2 and 2H2 in methanogenic bacteria is coupled with primary electrogenic Na+ translocation at a stoichiometry of 2-3 Na+/CO2. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 184:223-32. [PMID: 2550228 DOI: 10.1111/j.1432-1033.1989.tb15010.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cell suspensions of Methanosarcina barkeri were found to oxidize formaldehyde to CO2 and 2H2 (delta G0' = -27 kJ/mol CO2), when methanogenesis was inhibited by 2-bromoethanesulfonate. We report here that this reaction is coupled with (a) primary electrogenic Na+ translocation at a stoichiometry of 2-3 Na+/CO2, (b) with secondary H+ translocation via a Na+/H+ antiporter and (c) with ATP synthesis driven by an electrochemical proton potential. This is concluded from the following findings. Formaldehyde oxidation to CO2 and 2H2 was dependent on Na+ ions, 2-3 mol Na+/mol formaldehyde oxidized were extruded. Na+ translocation was inhibited by Na+ ionophores, but not affected by protonophores of Na+/H+ antiport inhibitors. Formaldehyde oxidation was associated with the build up of a membrane potential in the order of 100 mV (inside negative), which could be dissipated by sodium ionophores rather than by protonophores. Formaldehyde oxidation was coupled with ATP synthesis, which could be inhibited by Na+ ionophores, Na+/H+ antiport inhibitors, by protonophores and by the H+-translocating-ATP-synthase inhibitor, dicyclohexylcarbodiimide. With cell suspensions of Methanobacterium thermoautotrophicum similar results were obtained.
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Affiliation(s)
- B Kaesler
- Fachbereich Biologie-Mikrobiologie, Philipps-Universität Marburg
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43
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Function of methanofuran, tetrahydromethanopterin, and coenzyme F420 in Archaeoglobus fulgidus. Arch Microbiol 1989. [DOI: 10.1007/bf00425174] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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44
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Karrasch M, Börner G, Enssle M, Thauer RK. Formylmethanofuran dehydrogenase from methanogenic bacteria, a molybdoenzyme. FEBS Lett 1989; 253:226-30. [PMID: 2759240 DOI: 10.1016/0014-5793(89)80964-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Formylmethanofuran dehydrogenase, a key enzyme of methanogenesis, was purified 100-fold from methanol grown Methanosarcina barkeri to apparent homogeneity and a specific activity of 34 mumol.min-1.mg protein-1. Molybdenum was found to co-migrate with the enzyme activity. The molybdenum content of purified preparations was 3-4 nmol per mg protein equal to 0.6-0.8 mol molybdenum per mol enzyme of apparent molecular mass 200 kDa. Evidence is presented that also formylmethanofuran dehydrogenase from H2/CO2 grown Methanobacterium thermoautotrophicum (strain Marburg) is a molybdoenzyme.
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Affiliation(s)
- M Karrasch
- Laboratorium für Mikrobiologie, Fachbereich Biologie, Philipps-Universität, Marburg, FRG
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