Glucose-6-phosphate dehydrogenase from the hyperthermophilic bacterium<i>Thermotoga maritima</i>: expression of the<i>g6pd</i>gene and characterization of an extremely thermophilic enzyme

Hansen, Thomas; Schlichting, Bettina; Schönheit, Peter

doi:10.1111/j.1574-6968.2002.tb11443.x

Cited by 44 publications

(22 citation statements)

References 22 publications

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“…Attempts were made in Fig. 6 to plot the rate constants compiled from literature sources for several thermophilic enzymes (Raybuck et al 1991;Ro et al 1996;Breitung et al 1992 ;Bharadwaj & Maheshwari 1999 ;Chiba et al 1999;Duewel et al 1999;Doyle et al 2000;Manco et al 2001;Yasugi et al 2001;Hansen et al 2002a, b ;Nguyen et al 2002). The rate constants (k cat ) of thermophilic enzymes are in the range 2r10 0 -3.5r10 4 s x1 and do not largely differ from those of enzymes from mesophiles; however, the trend that the values of k cat /K m are in a narrow range was not clearly observed.…”

Section: The Formation Of Phosphodiester Bonds At High Temperaturesmentioning

confidence: 93%

“…The reaction rates with modern enzymes at temperatures of 25-90 xC are in a relatively narrow range compared with the range of the background reaction rates. Naturally, the enzymatic reaction rates for thermophilic organisms should be much greater than the reaction (Steyaert et al 1991 ;Schultz et al 1998) and RNA polymerase (Maslak & Martin 1993) ; closed triangles at 50-90 xC (within the upper-right box): the rate constants with several types of thermophilic enzymes (Raybuck et al 1991;Breitung et al 1992 ;Ro et al 1996 ;Bharadwaj & Maheshwari 1999 ;Chiba et al 1999 ;Duewel et al 1999 ;Doyle et al 2000;Manco et al 2001 ;Yasugi et al 2001 ;Hansen et al 2002a, b;Nguyen et al 2002) (Kawamura 2000(Kawamura , 2003a; open triangles: the cyclization of 5k-GCGCGrC .…”

Section: The Formation Of Phosphodiester Bonds At High Temperaturesmentioning

confidence: 99%

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Behaviour of RNA under hydrothermal conditions and the origins of life

Kawamura¹

2004

International Journal of Astrobiology

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The RNA world hypothesis and the hydrothermal origin of life hypothesis are contradictory to each other. Although it is considered that RNA molecules are too labile to maintain life-like systems at high temperatures and there is extensive literature on nucleic acid hydrolysis, the stability and the chemical evolution of RNA have not been sufficiently analysed from the viewpoint of hydrothermal reactions. Based on our experimental data concerning the stability and the prebiotic formation of RNA at high temperatures, two different aspects seem to be important for evaluating whether RNA molecules are too labile. First, the stability of RNA molecules should be evaluated from the comparison of the rate of formation and the rate of degradation of RNA in open systems. Our prebiotic reaction models of phosphodiester bond formation suggest that at high temperatures the accumulation of RNA may be possible. However, an RNA world entirely consisting of RNA molecules is unlikely to occur because the biologically important interactions are not effective for the bare RNA molecules at high temperatures. Second, since enzymes presently mediate most biological reactions, evaluation of the accumulation of RNA should be based on the comparison between the enzymatic and non-enzymatic reaction rates. Hence, the evaluation of the primitive enzymatic reaction rates at high temperatures has been attempted. There is a large difference between the present enzymatic reaction rates at 25-90 xC and the non-enzymatic reaction rates at high temperatures of 200-300 xC. It is thus possible that prebiotic enzyme-like assemblies could have facilitated the accumulation of RNA molecules at hydrothermal vent temperatures.

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Section: The Formation Of Phosphodiester Bonds At High Temperaturesmentioning

confidence: 93%

Section: The Formation Of Phosphodiester Bonds At High Temperaturesmentioning

confidence: 99%

Behaviour of RNA under hydrothermal conditions and the origins of life

Kawamura¹

2004

International Journal of Astrobiology

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“…G6PDH has been characterized, e.g., for Tmt. maritima (279), and the crystal structure has been reported, e.g., for the enzyme from Leuconostoc mesenteroides (280) (Fig. 13B).…”

Section: Bacteria Eukaryamentioning

confidence: 99%

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

Bräsen

Esser

Rauch

et al. 2014

Microbiol Mol Biol Rev

271

294

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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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“…PGI activity (G6P 7 F6P) was determined in both directions. The formation of glucose 6-phosphate (G6P) was investigated by coupling it to the reduction of NADP ϩ either via yeast (20 -50°C) or via hyperthermophilic Thermotoga maritima glucose 6-phosphate dehydrogenase (50 -95°C) (41). The standard assay I contained 100 mM Tris/HCl, 0.5 mM NADP ϩ , 5 mM fructose 6-phosphate (F6P), and 1.1 units of glucose 6-phosphate dehydrogenase.…”

Section: Methodsmentioning

confidence: 99%

Bifunctional Phosphoglucose/Phosphomannose Isomerases from the Archaea Aeropyrum pernix and Thermoplasma acidophilum Constitute a Novel Enzyme Family within the Phosphoglucose Isomerase Superfamily

Hansen

Wendorff

Schönheit

2004

Journal of Biological Chemistry

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The hyperthermophilic crenarchaeon Aeropyrum pernix contains phosphoglucose isomerase (PGI) activity. However, obvious homologs with significant identity to known PGIs could not be identified in the sequenced genome of this organism. The PGI activity from A. pernix was purified and characterized. Kinetic analysis revealed that, unlike all known PGIs, the enzyme catalyzed reversible isomerization not only of glucose 6-phosphate but also of epimeric mannose 6-phosphate at similar catalytic efficiency, thus defining the protein as bifunctional phosphoglucose/phosphomannose isomerase (PGI/PMI). The gene pgi/pmi encoding PGI/PMI (open reading frame APE0768) was identified by matrixassisted laser desorption ionization time-of-flight analyses; the gene was overexpressed in Escherichia coli as functional PGI/PMI. Putative PGI/PMI homologs were identified in several (hyper)thermophilic archaea and two bacteria. The homolog from Thermoplasma acidophilum (Ta1419) was overexpressed in E. coli, and the recombinant enzyme was characterized as bifunctional PGI/PMI. PGI/PMIs showed low sequence identity to the PGI superfamily and formed a distinct phylogenetic cluster. However, secondary structure predictions and the presence of several conserved amino acids potentially involved in catalysis indicate some structural and functional similarity to the PGI superfamily. Thus, we propose that bifunctional PGI/PMI constitutes a novel protein family within the PGI superfamily.Phosphoglucose isomerase (PGI 1 ; EC 5.3.1.9) catalyzes the reversible isomerization of glucose 6-phosphate to fructose 6-phosphate. PGI plays a central role in sugar metabolism of eukarya, bacteria, and Archaea both in glycolysis via the Embden-Meyerhof pathway in eukarya and bacteria and in its modified versions found in Archaea. PGI is also involved in gluconeogenesis where the enzyme operates in the reverse direction (for the literature see Refs. 1-3). PGIs from the domains of eukarya and bacteria are well studied enzymes. A variety of PGIs have been purified and biochemically characterized, and the encoding genes have been cloned and sequenced (e.g. Refs. 4 -11). Crystal structures have been determined for the eukaryotic PGIs from pig, rabbit, human, and from the bacterium Bacillus stearothermophilus, and conserved amino acids proposed to be involved in substrate binding and/or catalysis have been identified (12-15, 17, 18, 20 -25). The eukaryal and bacterial PGIs belong to the PGI superfamily defined by its two conserved signature patternsTo date this superfamily includes more than 300 PGI sequences (see www.sanger.ac.uk/cgi-bin/Pfam/getacc?PF00342) (26) from bacteria and eukarya but only three from the archaeal domain. These include the PGI from the hyperthermophilic euryarchaeon Methanococcus jannaschii (MjPGI). This PGI has recently been characterized as the first archaeal member of the PGI superfamily. 2 So far little is known about other archaeal PGIs. Recently, two other euryarchaeal PGIs have been characterized, one from the hyperthermophilic euryarch...

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Glucose-6-phosphate dehydrogenase from the hyperthermophilic bacteriumThermotoga maritima: expression of theg6pdgene and characterization of an extremely thermophilic enzyme

Cited by 44 publications

References 22 publications

Behaviour of RNA under hydrothermal conditions and the origins of life

Behaviour of RNA under hydrothermal conditions and the origins of life

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

Bifunctional Phosphoglucose/Phosphomannose Isomerases from the Archaea Aeropyrum pernix and Thermoplasma acidophilum Constitute a Novel Enzyme Family within the Phosphoglucose Isomerase Superfamily

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