Publications

• Elucidation of methanogenic coenzyme biosyntheses: from spectroscopy to genomics.

  Graham D.E., White R.H.

  Methanogenesis, the anaerobic production of methane from CO2 or simple carbon compounds, requires seven organic coenzymes. This review describes pathways for the biosynthesis of methanofuran, 5,6,7,8-tetrahydromethanopterin, coenzyme F420, coenzyme M (2-mercaptoethanesulfonic acid) and coenzyme B ... >> More

  Methanogenesis, the anaerobic production of methane from CO2 or simple carbon compounds, requires seven organic coenzymes. This review describes pathways for the biosynthesis of methanofuran, 5,6,7,8-tetrahydromethanopterin, coenzyme F420, coenzyme M (2-mercaptoethanesulfonic acid) and coenzyme B (7-mercaptoheptanoyl-L-threonine phosphate). Spectroscopic evidence for the pathways is reviewed and recent efforts are described to identify and characterize the biosynthetic enzymes from methanogenic archaea. The literature from 1971 to September 2001 is reviewed, and 169 references are cited. << Less

  Nat Prod Rep 19:133-147(2002) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Identification of an archaeal 2-hydroxy acid dehydrogenase catalyzing reactions involved in coenzyme biosynthesis in methanoarchaea.

  Graupner M., Xu H., White R.H.

  Two putative malate dehydrogenase genes, MJ1425 and MJ0490, from Methanococcus jannaschii and one from Methanothermus fervidus were cloned and overexpressed in Escherichia coli, and their gene products were tested for the ability to catalyze pyridine nucleotide-dependent oxidation and reduction re ... >> More

  Two putative malate dehydrogenase genes, MJ1425 and MJ0490, from Methanococcus jannaschii and one from Methanothermus fervidus were cloned and overexpressed in Escherichia coli, and their gene products were tested for the ability to catalyze pyridine nucleotide-dependent oxidation and reduction reactions of the following alpha-hydroxy-alpha-keto acid pairs: (S)-sulfolactic acid and sulfopyruvic acid; (S)-alpha-hydroxyglutaric acid and alpha-ketoglutaric acid; (S)-lactic acid and pyruvic acid; and 1-hydroxy-1,3,4,6-hexanetetracarboxylic acid and 1-oxo-1,3,4, 6-hexanetetracarboxylic acid. Each of these reactions is involved in the formation of coenzyme M, methanopterin, coenzyme F(420), and methanofuran, respectively. Both the MJ1425-encoded enzyme and the MJ0490-encoded enzyme were found to function to different degrees as malate dehydrogenases, reducing oxalacetate to (S)-malate using either NADH or NADPH as a reductant. Both enzymes were found to use either NADH or NADPH to reduce sulfopyruvate to (S)-sulfolactate, but the V(max)/K(m) value for the reduction of sulfopyruvate by NADH using the MJ1425-encoded enzyme was 20 times greater than any other combination of enzymes and pyridine nucleotides. Both the M. fervidus and the MJ1425-encoded enzyme catalyzed the NAD(+)-dependent oxidation of (S)-sulfolactate to sulfopyruvate. The MJ1425-encoded enzyme also catalyzed the NADH-dependent reduction of alpha-ketoglutaric acid to (S)-hydroxyglutaric acid, a component of methanopterin. Neither of the enzymes reduced pyruvate to (S)-lactate, a component of coenzyme F(420). Only the MJ1425-encoded enzyme was found to reduce 1-oxo-1,3,4,6-hexanetetracarboxylic acid, and this reduction occurred only to a small extent and produced an isomer of 1-hydroxy-1,3,4,6-hexanetetracarboxylic acid that is not involved in the biosynthesis of methanofuran c. We conclude that the MJ1425-encoded enzyme is likely to be involved in the biosynthesis of both coenzyme M and methanopterin. << Less

  J. Bacteriol. 182:3688-3692(2000) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• The putative L-lactate dehydrogenase from Methanococcus jannaschii is an NADPH-dependent L-malate dehydrogenase.

  Madern D.

  The enzyme encoded by Methanococcus jannaschii open reading frame (ORF) 0490 was purified and characterized. It was shown to be an NADPH-dependent [lactate dehydrogenase (LDH)-like] L-malate dehydrogenase (MalDH) and not an L-lactate dehydrogenase, as had been suggested previously on the basis of ... >> More

  The enzyme encoded by Methanococcus jannaschii open reading frame (ORF) 0490 was purified and characterized. It was shown to be an NADPH-dependent [lactate dehydrogenase (LDH)-like] L-malate dehydrogenase (MalDH) and not an L-lactate dehydrogenase, as had been suggested previously on the basis of amino acid sequence similarity. The results show the importance of biochemical data in the assignment of ORF function in genomic sequences and have implications for the phylogenetic distribution of members of the MalDH/LDH enzyme superfamilies within the prokaryotic kingdom. << Less

  Mol. Microbiol. 37:1515-1520(2000) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• The first examples of (S)-2-hydroxyacid dehydrogenases catalyzing the transfer of the pro-4S hydrogen of NADH are found in the archaea.

  Graupner M., White R.H.

  Reduction of 2-oxoacids to the corresponding (S)-2-hydroxyacids is an important transformation in biochemistry. To date all (S)-2-hydroxyacid dehydrogenases belonging to the L-lactate/L-malate dehydrogenase family have been found to transfer the pro-4R hydrogen of either NADH or NADPH to C-2 of th ... >> More

  Reduction of 2-oxoacids to the corresponding (S)-2-hydroxyacids is an important transformation in biochemistry. To date all (S)-2-hydroxyacid dehydrogenases belonging to the L-lactate/L-malate dehydrogenase family have been found to transfer the pro-4R hydrogen of either NADH or NADPH to C-2 of the 2-oxoacid substrates during their reduction. Here, we report that recombinantly generated (S)-2-hydroxyacid dehydrogenases present in the methanoarchaea Methanococcus jannaschii and Methanothermus fervidus use the pro-4S hydrogen of NADH to reduce a series of 2-oxoacids to the corresponding (S)-2-hydroxyacids. This information as well as the low sequence identity between these archaeal enzymes and the L-lactate/L-malate family of enzymes indicate that these enzymes are not evolutionary related and therefore constitute a new class of (S)-2-hydroxyacid dehydrogenases. << Less

  Biochim Biophys Acta 1548:169-173(2001) [PubMed] [EuropePMC]

• Dissimilation of cysteate via 3-sulfolactate sulfo-lyase and a sulfate exporter in Paracoccus pantotrophus NKNCYSA.

  Rein U., Gueta R., Denger K., Ruff J., Hollemeyer K., Cook A.M.

  Paracoccus pantotrophus NKNCYSA utilizes (R)-cysteate (2-amino-3-sulfopropionate) as a sole source of carbon and energy for growth, with either nitrate or molecular oxygen as terminal electron acceptor, and the specific utilization rate of cysteate is about 2 mkat (kg protein)(-1). The initial deg ... >> More

  Paracoccus pantotrophus NKNCYSA utilizes (R)-cysteate (2-amino-3-sulfopropionate) as a sole source of carbon and energy for growth, with either nitrate or molecular oxygen as terminal electron acceptor, and the specific utilization rate of cysteate is about 2 mkat (kg protein)(-1). The initial degradative reaction is catalysed by an (R)-cysteate : 2-oxoglutarate aminotransferase, which yields 3-sulfopyruvate. The latter was reduced to 3-sulfolactate by an NAD-linked sulfolactate dehydrogenase [3.3 mkat (kg protein)(-1)]. The inducible desulfonation reaction was not detected initially in cell extracts. However, a strongly induced protein with subunits of 8 kDa (alpha) and 42 kDa (beta) was found and purified. The corresponding genes had similarities to those encoding altronate dehydratases, which often require iron for activity. The purified enzyme could then be shown to convert 3-sulfolactate to sulfite and pyruvate and it was termed sulfolactate sulfo-lyase (Suy). A high level of sulfite dehydrogenase was also induced during growth with cysteate, and the organism excreted sulfate. A putative regulator, OrfR, was encoded upstream of suyAB on the reverse strand. Downstream of suyAB was suyZ, which was cotranscribed with suyB. The gene, an allele of tauZ, encoded a putative membrane protein with transmembrane helices (COG2855), and is a candidate to encode the sulfate exporter needed to maintain homeostasis during desulfonation. suyAB-like genes are widespread in sequenced genomes and environmental samples where, in contrast to the current annotation, several presumably encode the desulfonation of 3-sulfolactate, a component of bacterial spores. << Less

  Microbiology 151:737-747(2005) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Refolding, characterization and crystal structure of (S)-malate dehydrogenase from the hyperthermophilic archaeon Aeropyrum pernix.

  Kawakami R., Sakuraba H., Goda S., Tsuge H., Ohshima T.

  Tartrate oxidation activity was found in the crude extract of an aerobic hyperthermophilic archaeon Aeropyrum pernix, and the enzyme was identified as (S)-malate dehydrogenase (MDH), which, when produced in Escherichia coli, was mainly obtained as an inactive inclusion body. The inclusion body was ... >> More

  Tartrate oxidation activity was found in the crude extract of an aerobic hyperthermophilic archaeon Aeropyrum pernix, and the enzyme was identified as (S)-malate dehydrogenase (MDH), which, when produced in Escherichia coli, was mainly obtained as an inactive inclusion body. The inclusion body was dissolved in 6 M guanidine-HCl and gradually refolded to the active enzyme through dilution of the denaturant. The purified recombinant enzyme consisted of four identical subunits with a molecular mass of about 110 kDa. NADP was preferred as a coenzyme over NAD for (S)-malate oxidation and, unlike MDHs from other sources, this enzyme readily catalyzed the oxidation of (2S,3S)-tartrate and (2S,3R)-tartrate. The tartrate oxidation activity was also observed in MDHs from the hyperthermophilic archaea Methanocaldococcus jannaschii and Archaeoglobus fulgidus, suggesting these hyperthermophilic MDHs loosely bind their substrates. The refolded A. pernix MDH was also crystallized, and the structure was determined at a resolution of 2.9 A. Its overall structure was similar to those of the M. jannaschii, Chloroflexus aurantiacus, Chlorobium vibrioforme and Cryptosporidium parvum [lactate dehydrogenase-like] MDHs with root-mean-square-deviation values between 1.4 and 2.1 A. Consistent with earlier reports, Ala at position 53 was responsible for coenzyme specificity, and the next residue, Arg, was important for NADP binding. Structural comparison revealed that the hyperthermostability of the A. pernix MDH is likely attributable to its smaller cavity volume and larger numbers of ion pairs and ion-pair networks, but the molecular strategy for thermostability may be specific for each enzyme. << Less

  Biochim. Biophys. Acta 1794:1496-1504(2009) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.