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G D Vogels

Publications and source records attributed to G D Vogels.

At least 73 records · Page 4Linked to original sources
PubMed1989

Structural characterization of tatiopterin, a novel pterin isolated from Methanogenium tationis.

Cofactor extracts of Methanogenium tationis were screened for the presence of pterin-derivatives. Methanopterin, sarcinapterin and 7-methylpterin were absent, while 2-amino-4-hydroxy-pteridine and another blue fluorescent compound with a pterin spectrum were detected. The latter pterin was purified by ion exchange and reversed-phase column chromatography. The structure of this compound was elucidated by combining spectrophotometry, amino acid analysis and 1H-NMR spectroscopy. The pterin, which we named tatiopterin, was identified as an aspartyl derivative of sarcinapterin with a 7-proton instead of a 7-methyl group in the pterin moiety. The IUPAC name is: N-[-1'-(2''-amino-4''-hydroxy-7''-proton-6''-pteridinyl)ethyl]-4- [2',3',4',5'-tetrahydroxypent-1'-yl(5'----1'')O-alpha- ribofuranosyl-5''-phosphoric acid]aniline, in which the phosphate group is esterified with alpha-hydroxyglutarylglutamylaspartic acid.

Amino Acids↗
PubMed1988

Inorganic pyrophosphate synthesis during methanogenesis from methylcoenzyme M by cell-free extracts of Methanobacterium thermoautotrophicum (strain delta H).

Cell-free extracts of Methanobacterium thermoautotrophicum (strain delta H) were found to contain high concentrations of inorganic pyrophosphate (up to 40 mM). The compound was accumulated by the organism despite high activity of inorganic pyrophosphatase which was found to be present in the cell extracts (1-2 mumol min-1 mg protein-1). This activity was strongly inhibited at [PPi] greater than 1.0 mM. It was demonstrated that PPi synthesis occurred during methylcoenzyme M reduction under hydrogen atmosphere: in the first stage of the reaction for each mole of methane formed one mole of PPi was produced. Inhibition of the methylcoenzyme M reduction by 2-bromoethanesulfonic acid or by high concentrations (greater than 3 microM) of tetrachlorosalicylanilide also inhibited PPi synthesis. In contrast, low concentrations (1.3 microM) of tetrachlorosalicylanilide only inhibited PPi synthesis to the same extent as the methylcoenzyme M reduction was affected. In a later stage of the methylcoenzyme M reduction, PPi synthesis dropped and a second, as yet unidentified, unstable compound was formed. Synthesis of this compound also paralleled methane formation in a stoichiometric way and was affected by the inhibiting substances in a similar way as PPi synthesis.

Adenosine Triphosphatases↗
PubMed1988

Interconversion of F430 derivatives of methanogenic bacteria.

F430 is the prosthetic group of the methylcoenzyme M reductase of methanogenic bacteria. The compound isolated from Methanosarcina barkeri appears to be identical to the one obtained from the only distinctly related Methanobacterium thermoautotrophicum. F430 is thermolabile and in the presence of acetonitrile or C10-4 two epimerization products are obtained upon heating; in the absence of these compounds F430 is oxidized to 12,13-didehydro-F430. The latter is stereoselectively reduced under H2 atmosphere to F430 by cell-free extracts of M. barkeri or M. thermoautotrophicum. H2 may be replaced by the reduced methanogenic electron carrier coenzyme F420.

Chromatography, High Pressure Liquid↗
PubMed1988

Relationship between Methanogenic Cofactor Content and Maximum Specific Methanogenic Activity of Anaerobic Granular Sludges.

In this study we investigated whether a relationship exists between the methanogenic activity and the content of specific methanogenic cofactors of granular sludges cultured on different combinations of volatile fatty acids in upflow anaerobic sludge blanket or fluidized-bed reactors. Significant correlations were measured in both cases between the contents of coenzyme F(420)-2 or methanopterin and the maximum specific methanogenic activities on propionate, butyrate, and hydrogen, but not acetate. For both sludges the content of sarcinapterin appeared to be correlated with methanogenic activities on propionate, butyrate, and acetate, but not hydrogen. Similar correlations were measured with regard to the total content of coenzyme F(420)-4 and F(420)-5 in sludges from fluidized-bed reactors. The results indicate that the contents of specific methanogenic cofactors measured in anaerobic granular sludges can be used to estimate the hydrogenotrophic or acetotrophic methanogenic potential of these sludges.

Journal Article↗
PubMed1988

Methanopterin and methanogenic bacteria.

Methanogenic bacteria comprise a selected group of microorganisms that derive their energy for growth from the hydrogen-dependent reduction of CO2 to methane or the disproportionation of reduced one-carbon compounds and acetate to CO2 and methane. In the reduction and oxidation steps at the formyl, hydroxymethyl and methyl level the one-carbon unit remains bound to the reduced form of methanopterin, a pterin derivative typical of methanogenic bacteria. In addition, the reduced methanopterin, 5,6,7,8-tetrahydromethanopterin, is involved in a number of anabolic reactions. Methanopterin is structurally and functionally the counterpart of folic acid found in other organisms. In this review the occurrence and properties of methanopterin and its derivatives, as well as the biosynthesis and the role in the different catabolic and anabolic reactions are discussed against the background of folic acid biochemistry.

Euryarchaeota↗
PubMed1988

7-methylpterin derivatives in extracts of methanogens characterized by a relatively low methanopterin content.

Cofactor extracts of five hydrogenotrophic methanogenic bacteria which contain relatively low amounts of methanopterin were screened for the presence of 7-methylpterin derivatives. Extracts of Methanospirillum hungatei, Methanobrevibacter smithii and Methanoplanus endosymbiosus were found to contain 7-methylpterin and methanopterin. These compounds were absent in extracts of Methanogenium thermophilicum and Methanogenium tatii. An unidentified methanopterin-like compound was detected in extracts of these two species and of Msp. hungatei, while a 7-methylpterin-like compound was found in extracts of Mp. endosymbiosus. A possible physiological role of the latter two compounds is discussed.

Biological Factors↗
PubMed1984

Derivatives of methanopterin, a coenzyme involved in methanogenesis.

Degradational studies of methanopterin, a coenzyme involved in methanogenesis, are reported. The results of these studies are in full accordance with the proposed structure of methanopterin as N-[1'-(2''-amino-4''-hydroxy-7'' -methyl-6''-pteridinyl)ethyl]-4-[2', 3', 4', 5'-tetrahydroxypent-1'-yl(5'-1'' )O-alpha-ribofuranosyl-5''-phosphoric acid] aniline in which the phosphate group is esterified with alpha-hydroxyglutaric acid. Acid hydrolysis of methanopterin cleaved the 5'----1'' glycosidic bond and yielded a 'hydrolytic product' which was identified as N-[1'-(2''-amino-4''-hydroxy-7'' -methyl-6''-pteridinyl)ethyl]-4-[2', 3', 4', 5'-tetrahydroxypent-1'-yl]aniline. Alkaline permanganate oxidation of methanopterin yielded 7-methylpterin-6-carboxylic acid. Catalytic (or enzymatic) hydrogenation of methanopterin gave a mixture of 6-ethyl-7-methyl-7,8-dihydropterin, 6-ethyl-7-methylpterin and a third compound, named methaniline which was identified as 4-[2', 3', 4', 5'-tetrahydroxypent-1'-yl(5'----1'')O-alpha -ribofuranosyl-5''-phosphoric acid]aniline, in which the phosphate group is esterified with alpha-hydroxyglutaric acid. Methanosarcina barkeri contains a closely related coenzyme called sarcinapterin, which was identified as a L-glutamyl derivative of methanopterin, where the glutamate moiety is attached to the alpha-carboxylic acid group of the alpha-hydroxyglutaric acid moiety of methanopterin via an amide linkage.

Chemical Phenomena↗
PubMed1984

Reductive activation of methanol: 5-hydroxybenzimidazolylcobamide methyltransferase of Methanosarcina barkeri.

Methanol: 5-hydroxybenzimidazolylcobamide methyltransferase (MT1) from Methanosarcina barkeri, which is one of the enzymes responsible for the transmethylation from methanol to coenzyme M, was found to be activated in the presence of hydrogenase and ferredoxin. This activation was shown to involve a reduction of the bound corrinoid to the Co (I) level, and was demonstrated by spectrophotometry and chemical conversion of reduced MT1 to its methylated form. The reducing system of hydrogenase and ferredoxin was able to reduce dithiols, like dithiodiethanesulfonate and cystine to their monomers, in the presence of a corrinoid, which acts as an electron carrier. The ferredoxin was purified 133-fold and was tentatively identified on the basis of spectral properties and iron content of 3.8-4.0 atoms iron per molecule ferredoxin (12,000 daltons).

Corrinoids↗
PubMed1984

Elucidation of the structure of methanopterin, a coenzyme from Methanobacterium thermoautotrophicum, using two-dimensional nuclear-magnetic-resonance techniques.

Methanopterin is a coenzyme involved in methanogenesis. From 2 kg wet cells of Methanobacterium thermoautotrophicum about 35 mumol methanopterin were isolated. The structure of this compound was elucidated by various two-dimensional nuclear-magnetic-resonance techniques. Methanopterin was identified as N-[1'-(2"-amino-4"-hydroxy-7" - methyl-6"- pteridinyl) ethyl]-4-[2',3',4',5'- tetrahydroxypent-1'- yl (5' leads to 1") O-alpha-ribofuranosyl-5"-phosphoric acid] aniline, in which the phosphate group is esterified with alpha-hydroxyglutaric acid. The molecular formula of the sodium salt of methanopterin at pH 7.0 is C30H38O16N6PNa3 X chiH2O (chi is about 4). The anhydrous sodium salt of methanopterin has a molecular mass of 838.60 Da and the molar absorption coefficient at 342 nm is 7.4 mM-1 cm-1 at pH 7.0.

Chemical Phenomena↗
PubMed1984

Stimulation of growth of Bacillus fastidiosus by amino acids.

Growth of Bacillus fastidiosus on allantoin is stimulated by components of rich media as was evident from a decreased generation time and an increased maximal growth yield in the presence of such media. Such a stimulation must involve various transport systems. Energy-dependent transport systems for some amino acids were demonstrated besides those for urate, allantoin and allantoate.

Amino Acids↗
PubMed1984

Methanogenesis: surprising molecules, microorganisms and ecosystems.

Methanogenesis involves a novel set of coenzymes as one-carbon and electron carriers. Consequently, metabolic processes of methanogens deviate from those present in non-methanogenic bacteria. Methanogenic bacteria can be classified on the basis of substrate utilization. Group I (24 species) grows at the expense of hydrogen plus CO2 and/or formate and group II (7 species) uses methanol and/or acetate. Hydrogen-consuming methanogens are found as epi- or endosymbionts of anaerobic ciliates.

Acetates↗
PubMed1984

Identification of 6-acetyl-7-methyl-7,8-dihydropterin as a degradation product of 5,10-methenyl-5,6,7,8-tetrahydromethanopterin.

During purification procedures and upon aerobic heating with alkali a green-yellow degradation fluorescent product (GY) was formed from 5,10-methenyl-5,6,7,8-tetrahydromethanopterin, an intermediate in the reduction of CO2 to methane [J. T. Keltjens, L. Daniels, H. G. Janssen, and G. D. Vogels (1983) Eur. J. Biochem. 130, 545-552]. GY was suggested to be a 6-(1-oxo)-7,8-dihydropterin. On the basis of the spectral properties and the results of degradation studies, it was now shown that the structure of GY is 6-acetyl-7-methyl-7,8-dihydropterin. This structure was confirmed by synthesis of the compound and other reference substances.

Chemical Phenomena↗
PubMed1984

Purification and properties of methanol:5-hydroxybenzimidazolylcobamide methyltransferase from Methanosarcina barkeri.

Methanol:5-hydroxybenzimidazolylcobamide methyltransferase from Methanosarcina barkeri has been purified to approximately 90% homogeneity by ion-exchange chromatography on DEAE-cellulose and QAE-A50 Sephadex columns. The molecular weight, estimated by gel electrophoresis, was found to be 122,000, and the enzyme contained two different subunits with molecular weights of 34,000 and 53,000, which indicates an alpha 2 beta structure. The enzyme contains three or four molecules of 5-hydroxybenzimidazolylcobamide, which could be removed by treatment of the enzyme with 2-mercaptoethanol or sodium dodecyl sulfate. In both cases the enzyme dissociated into its subunits. For stability, the enzyme required the presence of divalent cations such as Mg2+, Mn2+, Sr2+, Ca2+, or Ba2+. ATP, GTP, or CTP was needed in a reductive activation process of the enzyme. This activation was brought about by a mixture of H2, ferredoxin, and hydrogenase, but also by CO, which is thought to reduce the corrinoid chemically. The CO dehydrogenase-like activity of the methyltransferase is discussed.

Carbon Monoxide↗
PubMed1983

Structural elements of methanopterin, a novel pterin present in Methanobacterium thermoautotrophicum.

During short-time labeling experiments, cells of Methanobacterium thermoautotrophicum incorporate a substantial part of 14CO2 in a yellow fluorescent compound (called YFC) [Daniels, L. & Zeikus, J. G. (1978) J. Bacteriol. 136, 75-84]. As the compound was present only in small amounts, its more abundant, metabolic precursor was identified, extracted and purified by column chromatography. The chromophore of this compound is 2-amino-4-hydroxypteridine (pterin) as indicated by its ultraviolet-visible-light absorption and fluorescence properties. Decomposition studies revealed the presence of a number of structural elements, viz. glutamic acid, phosphate and a hexosamine. 1H-NMR and 13C-NMR spectra pointed to the presence of additional, as yet unidentified, elements. The compound is a complex, novel pterin derivative, which we have called methanopterin.

Chemical Phenomena↗
PubMed1983

A novel one-carbon carrier (carboxy-5,6,7,8-tetrahydromethanopterin) isolated from Methanobacterium thermoautotrophicum and derived from methanopterin.

During short-term labeling experiments, cells of Methanobacterium thermoautotrophicum incorporated a substantial part of 14CO2 in a compound with a bright yellow fluorescence on dry thin-layer chromatography plates and called yellow fluorescent compound (YFC) [Daniels, L. and Zeikus, J.G. (1978) J. Bacteriol. 136, 75-84]. This compound was extracted and purified by ion-exchange column chromatography with formic acid gradients up to 0.3 M. Out of 325 g wet cells of M. thermoautotrophicum about 4 mg of the compound were isolated. This material and some degradation products obtained from it were studied by means of chemical decomposition, ultraviolet-visible-light spectroscopy and preliminary 1H-NMR spectroscopy. It has structural elements in common with methanopterin (see preceding paper in this journal); these elements are a pterin group, glutamate, a hexosamine. The pterin in this compound is present in a reduced form, presumably as 5,6,7,8-tetrahydromethanopterin, and the additional one-carbon unit is probably present as a carboxy group. Probably the first step of methanogenesis implies a carboxylation of methanopterin and a concomitant reduction of the pterin. The trivial name carboxy-5,6,7,8-tetrahydromethanopterin is introduced for the compound.

Carbon↗
PubMed1983

Methyltransferases involved in methanol conversion by Methanosarcina barkeri.

2-(Methylthio)ethanesulfonate (CH3S-CoM) is formed as an intermediate in methanogenesis from methanol by cell-free extracts of Methanosarcina barkeri. The enzyme system involved in the methyl transfer from methanol to 2-mercaptoethanesulfonate (HS-CoM) was resolved into two enzyme fractions. One enzyme (methanol:5-hydroxy-benzimidazolylcobamide methyltransferase) appears to be a cobalamin-containing protein, which is oxygen sensitive. The other enzyme (Co-methyl-5-hydroxybenzimidazolylcobamide: HS-CoM methyltransferase) was purified. It is insensitive to oxygen and it transfers also the methylgroup from Co-methyl-5,6-dimethylbenzimidazolylcobamide to HS-CoM.

Chromatography, Ion Exchange↗
PubMed1983

Quantification of coenzymes and related compounds from methanogenic bacteria by high-performance liquid chromatography.

Quantification of coenzymes and related compounds from methanogens was performed in extracts obtained from whole cells with aqueous ethanol at 80 degrees C. By means of high-performance liquid chromatography the following compounds could be detected and quantified in extracts from Methanobacterium thermoautotrophicum: coenzyme MF430, the prosthetic group of methylcoenzyme M reductase, F560, an oxidation product of this compound, coenzyme F420, F342, methanopterin, and carboxytetrahydromethanopterin, previously known as YFC. Coenzyme MF430, coenzyme F420, and methanopterin could be determined in extracts from Methanosarcina barkeri. Structural differences were noticed between the coenzymes from the methanogenic bacteria studied.

Chromatography, High Pressure Liquid↗