Oxidation of organic compounds to CO2 with sulfur or thiosulfate as electron acceptor in the anaerobic hyperthermophilic archaea Thermoproteus tenax and Pyrobaculum islandicum proceeds via the citric acid cycle

Selig, Martina; Schönheit, Peter

doi:10.1007/bf00301853

Cited by 56 publications

(20 citation statements)

References 36 publications

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“…From the slope, an activation energy (E A ) of 51 kJ mol -1 was calculated. This is lower than the isocitrate dehydrogenase activation energies reported for crude isocitrate dehydrogenases from Thermoproteus tenax and Pyrobaculum islandicum, which are 72.1 and 84.2 kJ mol -1 , respectively (Selig and Schönheit 1994). The isocitrate dehydrogenase was inactivated following first-order kinetics when incubated at temperatures between 70 and 95°C (Fig.…”

Section: Catalytic Properties and Thermostabilitymentioning

confidence: 49%

Biochemical and phylogenetic characterization of isocitrate dehydrogenase from a hyperthermophilic archaeon, Archaeoglobus fulgidus

Steen

Lien

Birkeland

1997

Archives of Microbiology

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A thermostable homodimeric isocitrate dehydrogenase from the hyperthermophilic sulfate-reducing archaeon Archaeoglobus fulgidus was purified and characterized. The mol. mass of the isocitrate dehydrogenase subunit was 42 kDa as determined by SDS-PAGE. Following separation by SDS-PAGE, A. fulgidus isocitrate dehydrogenase could be renatured and detected in situ by activity staining. The enzyme showed dual coenzyme specificity with a high preference for NADP+. Optimal temperature for activity was 90 degrees C or above, and a half-life of 22 min was found for the enzyme when incubated at 90 degrees C in a 50 mM Tricine-KOH buffer (pH 8.0). Based on the N-terminal amino acid sequence, the gene encoding the isocitrate dehydrogenase was cloned. DNA sequencing identified the icd gene as an open reading frame encoding a protein of 412 amino acids with a molecular mass corresponding to that determined for the purified enzyme. The deduced amino acid sequence closely resembled that of the isocitrate dehydrogenase from the archaeon Caldococcus noboribetus (59% identity) and bacterial isocitrate dehydrogenases, with 57% identity with isocitrate dehydrogenase from Escherichia coli. All the amino acid residues directly contacting substrate and coenzyme (except Ile-320) in E. coli isocitrate dehydrogenase are conserved in the enzyme from A. fulgidus. The primary structure of A. fulgidus isocitrate dehydrogenase confirmes the presence of Bacteria-type isocitrate dehydrogenases among Archaea. Multiple alignment of all the available amino acid sequences of di- and multimeric isocitrate dehydrogenases from the three domains of life shows that they can be divided into three distinct phylogenetic groups.

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Section: Catalytic Properties and Thermostabilitymentioning

confidence: 49%

Biochemical and phylogenetic characterization of isocitrate dehydrogenase from a hyperthermophilic archaeon, Archaeoglobus fulgidus

Steen

Lien

Birkeland

1997

Archives of Microbiology

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“…KD(P)GA catalyzes the reversible cleavage of KDG and KDPG, yielding pyruvate as well as GA and GAP, respectively, and has been detected in all archaeal ED pathway utilizers (40,70,158,227,248,249). Initially, the enzyme from Sul.…”

Section: -Keto-3-deoxy-(6-phospho)gluconate Aldolase [Kd(p)ga]mentioning

confidence: 99%

“…tenax and Sulfolobus spp., crude extract measurements and sequence comparisons indicated the presence of a ferredoxin-dependent aldehyde oxidoreductase for GA oxidation to glycerate (84,158). A molybdate-containing AOR from Sul.…”

Section: Gap Conversionmentioning

confidence: 99%

“…A short electron transport chain via a single iron-nickel hydrogenase and two sulfur reductases, probably mediated by quinones, has been proposed (418). Under heterotrophic growth conditions, glucose was shown to be completely oxidized to CO 2 via the oxidative CAC (158). Energy conservation seems to proceed via a membranebound electron transport chain, and sulfur has been suggested as the final acceptor (sulfur respiration) (418).…”

Section: Thermoproteus Tenaxmentioning

confidence: 99%

“…As a respiring organism (sulfur respiration with S 0 as the terminal electron acceptor), Tpt. tenax oxidizes pyruvate, the product of both the modified EMP pathway as well as the branched ED pathway, to acetyl-CoA via POR and further to CO 2 via the CAC, and the respiratory chain represents the major source of energy in this organism (158,418).…”

Section: Fig 25mentioning

confidence: 99%

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Carbohydrate Metabolism in Archaea: Current Insights into Unusual Enzymes and Pathways and Their Regulation

Bräsen

Esser

Rauch

et al. 2014

Microbiol Mol Biol Rev

265

282

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SUMMARY The metabolism of Archaea , the third domain of life, resembles in its complexity those of Bacteria and lower Eukarya . However, this metabolic complexity in Archaea is accompanied by the absence of many “classical” pathways, particularly in central carbohydrate metabolism. Instead, Archaea are characterized by the presence of unique, modified variants of classical pathways such as the Embden-Meyerhof-Parnas (EMP) pathway and the Entner-Doudoroff (ED) pathway. The pentose phosphate pathway is only partly present (if at all), and pentose degradation also significantly differs from that known for bacterial model organisms. These modifications are accompanied by the invention of “new,” unusual enzymes which cause fundamental consequences for the underlying regulatory principles, and classical allosteric regulation sites well established in Bacteria and Eukarya are lost. The aim of this review is to present the current understanding of central carbohydrate metabolic pathways and their regulation in Archaea . In order to give an overview of their complexity, pathway modifications are discussed with respect to unusual archaeal biocatalysts, their structural and mechanistic characteristics, and their regulatory properties in comparison to their classic counterparts from Bacteria and Eukarya . Furthermore, an overview focusing on hexose metabolic, i.e., glycolytic as well as gluconeogenic, pathways identified in archaeal model organisms is given. Their energy gain is discussed, and new insights into different levels of regulation that have been observed so far, including the transcript and protein levels (e.g., gene regulation, known transcription regulators, and posttranslational modification via reversible protein phosphorylation), are presented.

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Dissimilatory Sulfate- and Sulfur-Reducing Prokaryotes

Rabus¹,

Hansen²,

Widdel³

2006

The Prokaryotes

262

209

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Oxidation of organic compounds to CO2 with sulfur or thiosulfate as electron acceptor in the anaerobic hyperthermophilic archaea Thermoproteus tenax and Pyrobaculum islandicum proceeds via the citric acid cycle

Cited by 56 publications

References 36 publications

Biochemical and phylogenetic characterization of isocitrate dehydrogenase from a hyperthermophilic archaeon, Archaeoglobus fulgidus

Biochemical and phylogenetic characterization of isocitrate dehydrogenase from a hyperthermophilic archaeon, Archaeoglobus fulgidus

Carbohydrate Metabolism in Archaea: Current Insights into Unusual Enzymes and Pathways and Their Regulation

Dissimilatory Sulfate- and Sulfur-Reducing Prokaryotes

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