Structural Studies on the 2.25-MDa Homomultimeric Phosphoenolpyruvate Synthase fromStaphylothermus marinus

Harauz, George; Cicicopol, Christiana; Hegerl, R.; Cejka, Zdenka; Goldie, Kenneth N.; Santarius, Ute; Engel, Andréas; Baumeister, Wolfgang

doi:10.1006/jsbi.1996.0044

Cited by 9 publications

(9 citation statements)

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“…The P. furiosus cells used in the current study were grown in a medium with a high maltose concentration (6), so the cells could well experience the metabolic imbalance that makes energy spilling advantageous. However, futile cycling between PEP and pyruvate a Data for the enzymes from E. coli (11,32,34), M. thermoautotrophicum (14,46), and S. marinus (8,17) were taken from the indicated references.…”

Section: Discussionmentioning

confidence: 99%

“…It is a cofactorless homodimer with a molecular mass of 150 kDa and catalyzes the phosphorylation of pyruvate by using ATP to generate PEP, AMP, and phosphate. Only two other PEP synthetases have been purified and examined to any extent, and both are from archaea, the moderately thermophilic methanogen Methanobacterium thermoautotrophicum (14) and the heterotrophic hyperthermophile Staphylothermus marinus (8,9,16,17). The quaternary structure of the former enzyme was not reported, but S. marinus PEP synthetase exists as a large homomultimeric complex containing 24 subunits (17).…”

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confidence: 99%

“…Only two other PEP synthetases have been purified and examined to any extent, and both are from archaea, the moderately thermophilic methanogen Methanobacterium thermoautotrophicum (14) and the heterotrophic hyperthermophile Staphylothermus marinus (8,9,16,17). The quaternary structure of the former enzyme was not reported, but S. marinus PEP synthetase exists as a large homomultimeric complex containing 24 subunits (17). Conversely, while the kinetic properties of the latter enzyme are unknown, those of the M. thermoautotrophicum enzyme are similar to those of E. coli PEP synthetase (14).…”

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confidence: 99%

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Phosphoenolpyruvate Synthetase from the Hyperthermophilic Archaeon Pyrococcus furiosus

2001

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]. In contrast to several other nucleotide-dependent enzymes from P. furiosus, PpsA has an absolute specificity for ATP as the phosphate-donating substrate. This is the first PpsA from a nonmethanogenic archaeon to be biochemically characterized. Its kinetic properties are consistent with a role in gluconeogenesis, although its relatively high cellular concentration (ϳ5% of the cytoplasmic protein) suggests an additional function possibly related to energy spilling. It is not known whether interconversion between the smaller, active and larger, inactive forms of the enzyme has any functional role.

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Section: Discussionmentioning

confidence: 99%

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Phosphoenolpyruvate Synthetase from the Hyperthermophilic Archaeon Pyrococcus furiosus

2001

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“…hospitalis and Metallosphaera sedula, respectively (316,317). An unusual multimeric form of PEPS has been identified in Staphylothermus marinus but was not functionally characterized in detail (318,319). From information on the thermodynamic, kinetic, and regulatory properties gained from detailed biochemical characterizations of archaeal PEPSs from Mba.…”

Section: Phosphoenolpyruvate Synthetasementioning

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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“…A set of 1157 images of negatively stained proteasomes were aligned and averaged using the single particle procedures of the EM software package (33).…”

Section: Image Processingmentioning

confidence: 99%

Architecture and Molecular Mechanism of PAN, the Archaeal Proteasome Regulatory ATPase

Medalia

Beer

Zwickl

et al. 2009

Journal of Biological Chemistry

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In Archaea, an hexameric ATPase complex termed PAN promotes proteins unfolding and translocation into the 20 S proteasome. PAN is highly homologous to the six ATPases of the eukaryotic 19 S proteasome regulatory complex. Thus, insight into the mechanism of PAN function may reveal a general mode of action mutual to the eukaryotic 19 S proteasome regulatory complex. In this study we generated a three-dimensional model of PAN from tomographic reconstruction of negatively stained particles. Surprisingly, this reconstruction indicated that the hexameric complex assumes a two-ring structure enclosing a large cavity. Assessment of distinct three-dimensional functional states of PAN in the presence of adenosine 5-O-(thiotriphosphate) and ADP and in the absence of nucleotides outlined a possible mechanism linking nucleotide binding and hydrolysis to substrate recognition, unfolding, and translocation. A novel feature of the ATPase complex revealed in this study is a gate controlling the "exit port" of the regulatory complex and, presumably, translocation into the 20 S proteasome. Based on our structural and biochemical findings, we propose a possible model in which substrate binding and unfolding are linked to structural transitions driven by nucleotide binding and hydrolysis, whereas translocation into the proteasome only depends upon the presence of an unfolded substrate and binding but not hydrolysis of nucleotide.In eukaryotic cells most protein breakdown in the cytosol and nucleus is catalyzed by the 26 S proteasome. This ϳ2.5-MDa (1) complex degrades ubiquitin-conjugated and certain non-ubiquitinated proteins in an ATP-dependent manner (2, 3). The 26 S complex is composed of one or two 19 S regulatory particles situated at the ends of the cylindrical 20 S proteasome. Within the 26 S complex, proteins are hydrolyzed in the 20 S proteasome. Tagged substrates, however, first bind to the 19 S regulatory particle, which catalyzes their unfolding and translocation into the 20 S subcomplex (4, 5). The 19 S regulatory particle consists of at least 17 different subunits (1, 6). Nine of these subunits form a "lid," whereas the other eight subunits, including six ATPases, comprise the base of the 19 S particle. Electron microscopy (7-10) as well as cross-linking experiments (11,12) have demonstrated that the six homologous ATPases are associated with the ␣ rings of the 20 S particle.Unlike eukaryotes, Archaea and certain eubacteria contain homologous 20 S particles but lack ubiquitin. Their proteasomes degrade proteins in association with a hexameric ATPase ring complex termed PAN (13). PAN appears to be the evolutionary precursor of the 19 S base, predating the coupling of ubiquitination and proteolysis in eukaryotes (14). In addition, PAN recognizes the bacterial targeting sequence ssrA (in analogy to the polyubiquitin conjugates in eukaryotes) and efficiently unfolds and translocates globular substrates, like green fluorescent protein, when tagged with ssrA (15). In both PAN and the 19 S proteasome regulatory complexes, AT...

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Structural Studies on the 2.25-MDa Homomultimeric Phosphoenolpyruvate Synthase fromStaphylothermus marinus

Cited by 9 publications

References 0 publications

Phosphoenolpyruvate Synthetase from the Hyperthermophilic Archaeon Pyrococcus furiosus

Phosphoenolpyruvate Synthetase from the Hyperthermophilic Archaeon Pyrococcus furiosus

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

Architecture and Molecular Mechanism of PAN, the Archaeal Proteasome Regulatory ATPase

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