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Liu H, Wang X, Shen P, Ni Y, Han X. The basic functions of phosphoglycerate kinase 1 and its roles in cancer and other diseases. Eur J Pharmacol 2022; 920:174835. [DOI: 10.1016/j.ejphar.2022.174835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/15/2022] [Indexed: 01/17/2023]
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Rojas-Pirela M, Andrade-Alviárez D, Rojas V, Kemmerling U, Cáceres AJ, Michels PA, Concepción JL, Quiñones W. Phosphoglycerate kinase: structural aspects and functions, with special emphasis on the enzyme from Kinetoplastea. Open Biol 2020; 10:200302. [PMID: 33234025 PMCID: PMC7729029 DOI: 10.1098/rsob.200302] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Phosphoglycerate kinase (PGK) is a glycolytic enzyme that is well conserved among the three domains of life. PGK is usually a monomeric enzyme of about 45 kDa that catalyses one of the two ATP-producing reactions in the glycolytic pathway, through the conversion of 1,3-bisphosphoglycerate (1,3BPGA) to 3-phosphoglycerate (3PGA). It also participates in gluconeogenesis, catalysing the opposite reaction to produce 1,3BPGA and ADP. Like most other glycolytic enzymes, PGK has also been catalogued as a moonlighting protein, due to its involvement in different functions not associated with energy metabolism, which include pathogenesis, interaction with nucleic acids, tumorigenesis progression, cell death and viral replication. In this review, we have highlighted the overall aspects of this enzyme, such as its structure, reaction kinetics, activity regulation and possible moonlighting functions in different protistan organisms, especially both free-living and parasitic Kinetoplastea. Our analysis of the genomes of different kinetoplastids revealed the presence of open-reading frames (ORFs) for multiple PGK isoforms in several species. Some of these ORFs code for unusually large PGKs. The products appear to contain additional structural domains fused to the PGK domain. A striking aspect is that some of these PGK isoforms are predicted to be catalytically inactive enzymes or ‘dead’ enzymes. The roles of PGKs in kinetoplastid parasites are analysed, and the apparent significance of the PGK gene duplication that gave rise to the different isoforms and their expression in Trypanosoma cruzi is discussed.
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Affiliation(s)
- Maura Rojas-Pirela
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaiso, Valparaiso 2373223, Chile
| | - Diego Andrade-Alviárez
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Verónica Rojas
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaiso, Valparaiso 2373223, Chile
| | - Ulrike Kemmerling
- Instituto de Ciencias Biomédicas, Universidad de Chile, Facultad de Medicina, Santiago de Chile 8380453, Santigo de Chile
| | - Ana J Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Paul A Michels
- Centre for Immunity, Infection and Evolution, The King's Buildings, Edinburgh EH9 3FL, UK.,Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3FL, UK
| | - Juan Luis Concepción
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
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Mandelman D, Ballut L, Wolff DA, Feller G, Gerday C, Haser R, Aghajari N. Structural determinants increasing flexibility confer cold adaptation in psychrophilic phosphoglycerate kinase. Extremophiles 2019; 23:495-506. [DOI: 10.1007/s00792-019-01102-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 05/21/2019] [Indexed: 11/30/2022]
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Tästensen JB, Schönheit P. Two distinct glyceraldehyde-3-phosphate dehydrogenases in glycolysis and gluconeogenesis in the archaeon Haloferax volcanii. FEBS Lett 2018; 592:1524-1534. [PMID: 29572819 DOI: 10.1002/1873-3468.13037] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/06/2018] [Accepted: 03/09/2018] [Indexed: 11/06/2022]
Abstract
The halophilic archaeon Haloferax volcanii degrades glucose via the semiphosphorylative Entner-Doudoroff pathway and can also grow on gluconeogenic substrates. Here, the enzymes catalysing the conversion of glyceraldehyde-3-phosphate (GAP) to 3-phosphoglycerate were analysed. The genome contains the genes gapI and gapII encoding two putative GAP dehydrogenases, and pgk encoding phosphoglycerate kinase (PGK). We show that gapI is functionally involved in sugar catabolism, whereas gapII is involved in gluconeogenesis. For pgk, an amphibolic function is indicated. This is the first report of the functional involvement of a phosphorylating glyceraldehyde-3-phosphate dehydrogenase and PGK in sugar catabolism in archaea. Phylogenetic analyses indicate that the catabolic gapI from H. volcanii is acquired from bacteria via lateral genetransfer, whereas the anabolic gapII as well as pgk are of archaeal origin.
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Affiliation(s)
- Julia-Beate Tästensen
- Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Germany
| | - Peter Schönheit
- Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Germany
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Kumar S, Prakash S, Gupta K, Dongre A, Balaram P, Balaram H. Unexpected functional implication of a stable succinimide in the structural stability of Methanocaldococcus jannaschii glutaminase. Nat Commun 2016; 7:12798. [PMID: 27677693 PMCID: PMC5052720 DOI: 10.1038/ncomms12798] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 08/01/2016] [Indexed: 11/16/2022] Open
Abstract
Protein ageing is often mediated by the formation of succinimide intermediates. These short-lived intermediates derive from asparaginyl deamidation and aspartyl dehydration and are rapidly converted into β-aspartyl or D-aspartyl residues. Here we report the presence of a highly stable succinimide intermediate in the glutaminase subunit of GMP synthetase from the hyperthermophile Methanocaldoccocus jannaschii. By comparing the biophysical properties of the wild-type protein and of several mutants, we show that the presence of succinimide increases the structural stability of the glutaminase subunit. The protein bearing this modification in fact remains folded at 100 °C and in 8 M guanidinium chloride. Mutation of the residue following the reactive asparagine provides insight into the factors that contribute to the hydrolytic stability of the succinimide. Our findings suggest that sequences that stabilize succinimides from hydrolysis may be evolutionarily selected to confer extreme thermal stability. Succinimide is a post-translational modification susceptible to rapid hydrolysis and generally associated with protein destabilisation. Here, the authors use mass spectroscopy to identify a stable succinimide intermediate that is responsible for the high thermostability of a thermophilic enzyme.
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Affiliation(s)
- Sanjeev Kumar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Sunita Prakash
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Kallol Gupta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Aparna Dongre
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Padmanabhan Balaram
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Hemalatha Balaram
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
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Carbohydrate metabolism in Archaea: current insights into unusual enzymes and pathways and their regulation. Microbiol Mol Biol Rev 2014; 78:89-175. [PMID: 24600042 DOI: 10.1128/mmbr.00041-13] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
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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Reddy GK, Wendisch VF. Characterization of 3-phosphoglycerate kinase from Corynebacterium glutamicum and its impact on amino acid production. BMC Microbiol 2014; 14:54. [PMID: 24593686 PMCID: PMC3996851 DOI: 10.1186/1471-2180-14-54] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 02/26/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Corynebacterium glutamicum cg1790/pgk encodes an enzyme active as a 3-phosphoglycerate kinase (PGK) (EC 2.7.2.3) catalyzing phosphoryl transfer from 1,3-biphosphoglycerate (bPG) to ADP to yield 3-phosphoglycerate (3-PG) and ATP in substrate chain phosphorylation. RESULTS C. glutamicum 3-phosphoglycerate kinase was purified to homogeneity from the soluble fraction of recombinant E. coli. PGK(His) was found to be active as a homodimer with molecular weight of 104 kDa. The enzyme preferred conditions of pH 7.0 to 7.4 and required Mg²⁺ for its activity. PGK(His) is thermo labile and it has shown maximal activity at 50-65°C. The maximal activity of PGK(His) was estimated to be 220 and 150 U mg-1 with KM values of 0.26 and 0.11 mM for 3-phosphoglycerate and ATP, respectively. A 3-phosphoglycerate kinase negative C. glutamicum strain ∆pgk was constructed and shown to lack the ability to grow under glycolytic or gluconeogenic conditions unless PGK was expressed from a plasmid to restore growth. When pgk was overexpressed in L-arginine and L-ornithine production strains the production increased by 8% and by 17.5%, respectively. CONCLUSION Unlike many bacterial PGKs, C. glutamicum PGK is active as a homodimer. PGK is essential for growth of C. glutamicum with carbon sources requiring glycolysis and gluconeogenesis. Competitive inhibition by ADP reveals the critical role of PGK in gluconeogenesis by energy charge. Pgk overexpression improved the productivity in L-arginine and L-ornithine production strains.
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Affiliation(s)
| | - Volker F Wendisch
- Genetics of Prokaryotes, Faculty of Biology & CeBiTec, University of Bielefeld, Bielefeld 33615, Germany.
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Kouril T, Esser D, Kort J, Westerhoff HV, Siebers B, Snoep JL. Intermediate instability at high temperature leads to low pathway efficiency for an in vitro reconstituted system of gluconeogenesis in Sulfolobus solfataricus. FEBS J 2013; 280:4666-80. [PMID: 23865479 DOI: 10.1111/febs.12438] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 07/04/2013] [Accepted: 07/11/2013] [Indexed: 01/22/2023]
Abstract
Four enzymes of the gluconeogenic pathway in Sulfolobus solfataricus were purified and kinetically characterized. The enzymes were reconstituted in vitro to quantify the contribution of temperature instability of the pathway intermediates to carbon loss from the system. The reconstituted system, consisting of phosphoglycerate kinase, glyceraldehyde 3-phosphate dehydrogenase, triose phosphate isomerase and the fructose 1,6-bisphosphate aldolase/phosphatase, maintained a constant consumption rate of 3-phosphoglycerate and production of fructose 6-phosphate over a 1-h period. Cofactors ATP and NADPH were regenerated via pyruvate kinase and glucose dehydrogenase. A mathematical model was constructed on the basis of the kinetics of the purified enzymes and the measured half-life times of the pathway intermediates. The model quantitatively predicted the system fluxes and metabolite concentrations. Relative enzyme concentrations were chosen such that half the carbon in the system was lost due to degradation of the thermolabile intermediates dihydroxyacetone phosphate, glyceraldehyde 3-phosphate and 1,3-bisphosphoglycerate, indicating that intermediate instability at high temperature can significantly affect pathway efficiency.
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Affiliation(s)
- Theresa Kouril
- Molecular Enzyme Technology and Biochemistry, Biofilm Centre, Faculty of Chemistry, University of Duisburg-Essen, Germany
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Conservation of functionally important global motions in an enzyme superfamily across varying quaternary structures. J Mol Biol 2012; 423:831-46. [PMID: 22935436 DOI: 10.1016/j.jmb.2012.08.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 08/16/2012] [Accepted: 08/17/2012] [Indexed: 11/21/2022]
Abstract
The α-d-phosphohexomutase superfamily comprises enzymes involved in carbohydrate metabolism that are found in all kingdoms of life. Recent biophysical studies have shown for the first time that several of these enzymes exist as dimers in solution, prompting an examination of the oligomeric state of all proteins of known structure in the superfamily (11 different proteins; 31 crystal structures) via computational and experimental analyses. We find that these proteins range in quaternary structure from monomers to tetramers, with 6 of the 11 known structures being likely oligomers. The oligomeric state of these proteins not only is associated in some cases with enzyme subgroup (i.e., substrate specificity) but also appears to depend on domain of life, with the two archaeal proteins existing as higher-order oligomers. Within the oligomers, three distinct interfaces are observed, one of which is found in both archaeal and bacterial proteins. Normal mode analysis shows that the topological arrangement of the oligomers permits domain 4 of each protomer to move independently as required for catalysis. Our analysis suggests that the advantages associated with protein flexibility in this enzyme family are of sufficient importance to be maintained during the evolution of multiple independent oligomers. This study is one of the first showing that global motions may be conserved not only within protein families but also across members of a superfamily with varying oligomeric structures.
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Matsubara K, Yokooji Y, Atomi H, Imanaka T. Biochemical and genetic characterization of the three metabolic routes in Thermococcus kodakarensis linking glyceraldehyde 3-phosphate and 3-phosphoglycerate. Mol Microbiol 2011; 81:1300-12. [PMID: 21736643 DOI: 10.1111/j.1365-2958.2011.07762.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In the classical Embden-Meyerhof (EM) pathway for glycolysis, the conversion between glyceraldehyde 3-phosphate (GAP) and 3-phosphoglycerate (3-PGA) is reversibly catalysed by phosphorylating GAP dehydrogenase (GAPDH) and phosphoglycerate kinase (PGK). In the Euryarchaeota Thermococcus kodakarensis and Pyrococcus furiosus, an additional gene encoding GAP:ferredoxin oxidoreductase (GAPOR) and a gene similar to non-phosphorylating GAP dehydrogenase (GAPN) are present. In order to determine the physiological roles of the three routes that link GAP and 3-PGA, we individually disrupted the GAPOR, GAPN, GAPDH and PGK genes (gor, gapN, gapDH and pgk respectively) of T. kodakarensis. The Δgor strain displayed no growth under glycolytic conditions, confirming its proposed function to generate reduced ferredoxin for energy generation in glycolysis. Surprisingly, ΔgapN cells also did not grow under glycolytic conditions, suggesting that GAPN plays a key role in providing NADPH under these conditions. Disruption of gor and gapN had no effect on gluconeogenic growth. Growth experiments with the ΔgapDH and Δpgk strains indicated that, unlike their counterparts in the classical EM pathway, GAPDH/PGK play a major role only in gluconeogenesis. Biochemical analyses indicated that T. kodakarensis GAPN did not recognize aldehyde substrates other than d-GAP, preferred NADP(+) as cofactor and was dramatically activated with glucose 1-phosphate.
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Affiliation(s)
- Kohei Matsubara
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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11
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Bao L, Chatterjee S, Lohmer S, Schomburg D. An irreversible and kinetically controlled process: thermal induced denaturation of L-2-hydroxyisocaproate dehydrogenase from Lactobacillus confusus. Protein J 2007; 26:143-51. [PMID: 17205397 DOI: 10.1007/s10930-006-9055-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The thermal denaturation of Lactobacillus confusus L-2-Hydroxyisocaproate Dehydrogenase (L-HicDH) has been studied by Differential Scanning Calorimetry (DSC). The stability of this enzyme has been investigated at different pH conditions. The results of this study indicate that the thermal denaturation of this enzyme is irreversible and the T(m) is dependent on the scan-rate, which suggests that the denaturation process of L-HicDH is kinetically determined. The heat capacity function of L-HicDH shows a single peak with the T(m) values between 52.14 degrees C and 55.89 degrees C at pH 7.0 at different scan rates. These results indicate that the whole L-HicDH could unfold as a single cooperative unit, and intersubunit interactions of this homotetrameric enzyme must play a significant role in the stabilization of the whole enzyme. The rate constant of the unfolding is analyzed as a first order kinetic constant with the Arrhenius equation, and the activation energy has been calculated. The variation of the activation energy values obtained with different methods does not support the validity of the one-step irreversible model. The denaturation pathway was described by a three-state model, N --> U --> F, in which the dissociation of the tetramer takes place as an irreversible step before the irreversible unfolding of the monomers. The calorimetric enthalpy associated with the irreversible dissociation and the calorimetric enthalpy associated with the unfolding of the monomer were obtained from the best fitting procedure. Thermal unfolding of L-HicDH was also studied using Circular Dichroism (CD) spectroscopy. Both methods yielded comparable values.
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Affiliation(s)
- Lide Bao
- Institute for Biochemistry, University of Cologne, Zuelpicher Strasse 47, 50674 Cologne, Germany.
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12
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Brouns SJJ, Walther J, Snijders APL, van de Werken HJG, Willemen HLDM, Worm P, de Vos MGJ, Andersson A, Lundgren M, Mazon HFM, van den Heuvel RHH, Nilsson P, Salmon L, de Vos WM, Wright PC, Bernander R, van der Oost J. Identification of the Missing Links in Prokaryotic Pentose Oxidation Pathways. J Biol Chem 2006; 281:27378-88. [PMID: 16849334 DOI: 10.1074/jbc.m605549200] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The pentose metabolism of Archaea is largely unknown. Here, we have employed an integrated genomics approach including DNA microarray and proteomics analyses to elucidate the catabolic pathway for D-arabinose in Sulfolobus solfataricus. During growth on this sugar, a small set of genes appeared to be differentially expressed compared with growth on D-glucose. These genes were heterologously overexpressed in Escherichia coli, and the recombinant proteins were purified and biochemically studied. This showed that D-arabinose is oxidized to 2-oxoglutarate by the consecutive action of a number of previously uncharacterized enzymes, including a D-arabinose dehydrogenase, a D-arabinonate dehydratase, a novel 2-keto-3-deoxy-D-arabinonate dehydratase, and a 2,5-dioxopentanoate dehydrogenase. Promoter analysis of these genes revealed a palindromic sequence upstream of the TATA box, which is likely to be involved in their concerted transcriptional control. Integration of the obtained biochemical data with genomic context analysis strongly suggests the occurrence of pentose oxidation pathways in both Archaea and Bacteria, and predicts the involvement of additional enzyme components. Moreover, it revealed striking genetic similarities between the catabolic pathways for pentoses, hexaric acids, and hydroxyproline degradation, which support the theory of metabolic pathway genesis by enzyme recruitment.
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Affiliation(s)
- Stan J J Brouns
- Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Hesselink van Suchtelenweg 4, 6703 CT Wageningen, the Netherlands.
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Snijders APL, Walther J, Peter S, Kinnman I, de Vos MGJ, van de Werken HJG, Brouns SJJ, van der Oost J, Wright PC. Reconstruction of central carbon metabolism inSulfolobus solfataricus using a two-dimensional gel electrophoresis map, stable isotope labelling and DNA microarray analysis. Proteomics 2006; 6:1518-29. [PMID: 16447154 DOI: 10.1002/pmic.200402070] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the last decade, an increasing number of sequenced archaeal genomes have become available, opening up the possibility for functional genomic analyses. Here, we reconstructed the central carbon metabolism in the hyperthermophilic crenarchaeon Sulfolobus solfataricus (glycolysis, gluconeogenesis and tricarboxylic acid cycle) on the basis of genomic, proteomic, transcriptomic and biochemical data. A 2-DE reference map of S. solfataricus grown on glucose, consisting of 325 unique ORFs in 255 protein spots, was created to facilitate this study. The map was then used for a differential expression study based on (15)N metabolic labelling (yeast extract + tryptone-grown cells (YT) vs. glucose-grown cells (G)). In addition, the expression ratio of the genes involved in carbon metabolism was studied using DNA microarrays. Surprisingly, only 3 and 14% of the genes and proteins, respectively, involved in central carbon metabolism showed a greater than two-fold change in expression level. All results are discussed in the light of the current understanding of central carbon metabolism in S. solfataricus and will help to obtain a system-wide understanding of this organism.
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Affiliation(s)
- Ambrosius P L Snijders
- Biological and Environmental Systems Group, Department of Chemical and Process Engineering, University of Sheffield, Sheffield, UK
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Zhang Y, Porcelli M, Cacciapuoti G, Ealick SE. The Crystal Structure of 5′-Deoxy-5′-methylthioadenosine Phosphorylase II from Sulfolobus solfataricus, a Thermophilic Enzyme Stabilized by Intramolecular Disulfide Bonds. J Mol Biol 2006; 357:252-62. [PMID: 16414070 DOI: 10.1016/j.jmb.2005.12.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 12/08/2005] [Accepted: 12/11/2005] [Indexed: 11/25/2022]
Abstract
The crystal structure of Sulfolobus solfataricus 5'-deoxy-5'-methylthioadenosine phosphorylase II (SsMTAPII) in complex with 5'-deoxy-5'-methylthioadenosine (MTA) and sulfate was determined to 1.45A resolution. The hexameric structure of SsMTAPII is a dimer-of-trimers with one active site per monomer. The oligomeric assembly of the trimer and the monomer topology of SsMTAPII are almost identical with trimeric human 5'-deoxy-5'-methylthioadenosine phosphorylase (hMTAP). SsMTAPII is the first reported hexameric member in the trimeric class of purine nucleoside phosphorylase (PNP) from Archaea. Unlike hMTAP, which is highly specific for MTA, SsMTAPII also accepts adenosine as a substrate. The residues at the active sites of SsMTAPII and hMTAP are almost identical. The broad substrate specificity of SsMTAPII may be due to the flexibility of the C-terminal loop. SsMTAPII is extremely thermoactive and thermostable. The three-dimensional structure of SsMTAPII suggests that the unique dimer-of-trimers quaternary structure, a CXC motif at the C terminus, and two pairs of intrasubunit disulfide bridges may play an important role in its thermal stability.
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Affiliation(s)
- Yan Zhang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-1301, USA
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15
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Hamilton-Brehm SD, Schut GJ, Adams MWW. Metabolic and evolutionary relationships among Pyrococcus Species: genetic exchange within a hydrothermal vent environment. J Bacteriol 2005; 187:7492-9. [PMID: 16237032 PMCID: PMC1272969 DOI: 10.1128/jb.187.21.7492-7499.2005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pyrococcus furiosus and Pyrococcus woesei grow optimally at temperatures near 100 degrees C and were isolated from the same shallow marine volcanic vent system. Hybridization of genomic DNA from P. woesei to a DNA microarray containing all 2,065 open reading frames (ORFs) annotated in the P. furiosus genome, in combination with PCR analysis, indicated that homologs of 105 ORFs present in P. furiosus are absent from the uncharacterized genome of P. woesei. Pulsed-field electrophoresis indicated that the sizes of the two genomes are comparable, and the results were consistent with the hypothesis that P. woesei lacks the 105 ORFs found in P. furiosus. The missing ORFs are present in P. furiosus mainly in clusters. These clusters include one cluster (Mal I, PF1737 to PF1751) involved in maltose metabolism and another cluster (PF0691 to PF0695) whose products are thought to remove toxic reactive nitrogen species. Accordingly, it was found that P. woesei, in contrast to P. furiosus, is unable to utilize maltose as a carbon source for growth, and the growth of P. woesei on starch was inhibited by addition of a nitric oxide generator. In P. furiosus the ORF clusters not present in P. woesei are bracketed by or are in the vicinity of insertion sequences or long clusters of tandem repeats (LCTRs). While the role of LCTRs in lateral gene transfer is not known, the Mal I cluster in P. furiosus is a composite transposon that undergoes replicative transposition. The same locus in P. woesei lacks any evidence of insertion activity, indicating that P. woesei is a sister or even the parent of P. furiosus. P. woesei may have acquired by lateral gene transfer more than 100 ORFs from other organisms living in the same thermophilic environment to produce the type strain of P. furiosus.
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Affiliation(s)
- Scott D Hamilton-Brehm
- Department of Biochemistry and Molecular Biology, Davison Life Sciences Complex, University of Georgia, Athens, GA 30602-7229, USA
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Saavedra E, Encalada R, Pineda E, Jasso-Chávez R, Moreno-Sánchez R. Glycolysis in Entamoeba histolytica. Biochemical characterization of recombinant glycolytic enzymes and flux control analysis. FEBS J 2005; 272:1767-83. [PMID: 15794763 DOI: 10.1111/j.1742-4658.2005.04610.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The synthesis of ATP in the human parasite Entamoeba histolytica is carried out solely by the glycolytic pathway. Little kinetic and structural information is available for most of the pathway enzymes. We report here the gene cloning, overexpression and purification of hexokinase, hexose-6-phosphate isomerase, inorganic pyrophosphate-dependent phosphofructokinase, fructose-1,6 bisphosphate aldolase (ALDO), triosephosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate kinase, phosphoglycerate mutase (PGAM), enolase, and pyruvate phosphate dikinase (PPDK) enzymes from E. histolytica. Kinetic characterization of these 10 recombinant enzymes was made, establishing the kinetic constants at optimal and physiological pH values, analyzing the effect of activators and inhibitors, and investigating the storage stability and oligomeric state. Determination of the catalytic efficiencies at the pH optimum and at pH values that resemble those of the amoebal trophozoites was performed for each enzyme to identify possible controlling steps. This analysis suggested that PGAM, ALDO, GAPDH, and PPDK might be flux control steps, as they showed the lowest catalytic efficiencies. An in vitro reconstruction of the final stages of glycolysis was made to determine their flux control coefficients. Our results indicate that PGAM and PPDK exhibit high control coefficient values at physiological pH.
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Affiliation(s)
- Emma Saavedra
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Tlalpan, México DF, México.
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17
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Ronimus RS, Morgan HW. Distribution and phylogenies of enzymes of the Embden-Meyerhof-Parnas pathway from archaea and hyperthermophilic bacteria support a gluconeogenic origin of metabolism. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2005; 1:199-221. [PMID: 15803666 PMCID: PMC2685568 DOI: 10.1155/2003/162593] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Enzymes of the gluconeogenic/glycolytic pathway (the Embden-Meyerhof-Parnas (EMP) pathway), the reductive tricarboxylic acid cycle, the reductive pentose phosphate cycle and the Entner-Doudoroff pathway are widely distributed and are often considered to be central to the origins of metabolism. In particular, several enzymes of the lower portion of the EMP pathway (the so-called trunk pathway), including triosephosphate isomerase (TPI; EC 5.3.1.1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12/13), phosphoglycerate kinase (PGK; EC 2.7.2.3) and enolase (EC 4.2.1.11), are extremely well conserved and universally distributed among the three domains of life. In this paper, the distribution of enzymes of gluconeogenesis/glycolysis in hyperthermophiles--microorganisms that many believe represent the least evolved organisms on the planet--is reviewed. In addition, the phylogenies of the trunk pathway enzymes (TPIs, GAPDHs, PGKs and enolases) are examined. The enzymes catalyzing each of the six-carbon transformations in the upper portion of the EMP pathway, with the possible exception of aldolase, are all derived from multiple gene sequence families. In contrast, single sequence families can account for the archaeal and hyperthermophilic bacterial enzyme activities of the lower portion of the EMP pathway. The universal distribution of the trunk pathway enzymes, in combination with their phylogenies, supports the notion that the EMP pathway evolved in the direction of gluconeogenesis, i.e., from the bottom up.
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Affiliation(s)
- Ron S Ronimus
- Thermophile Research Unit, Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, New Zealand.
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18
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Walden H, Taylor GL, Lorentzen E, Pohl E, Lilie H, Schramm A, Knura T, Stubbe K, Tjaden B, Hensel R. Structure and Function of a Regulated Archaeal Triosephosphate Isomerase Adapted to High Temperature. J Mol Biol 2004; 342:861-75. [PMID: 15342242 DOI: 10.1016/j.jmb.2004.07.067] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Revised: 06/28/2004] [Accepted: 07/08/2004] [Indexed: 11/19/2022]
Abstract
Triosephophate isomerase (TIM) is a dimeric enzyme in eucarya, bacteria and mesophilic archaea. In hyperthermophilic archaea, however, TIM exists as a tetramer composed of monomers that are about 10% shorter than other eucaryal and bacterial TIM monomers. We report here the crystal structure of TIM from Thermoproteus tenax, a hyperthermophilic archaeon that has an optimum growth temperature of 86 degrees C. The structure was determined from both a hexagonal and an orthorhombic crystal form to resolutions of 2.5A and 2.3A, and refined to R-factors of 19.7% and 21.5%, respectively. In both crystal forms, T.tenax TIM exists as a tetramer of the familiar (betaalpha)(8)-barrel. In solution, however, and unlike other hyperthermophilic TIMs, the T.tenax enzyme exhibits an equilibrium between inactive dimers and active tetramers, which is shifted to the tetramer state through a specific interaction with glycerol-1-phosphate dehydrogenase of T.tenax. This observation is interpreted in physiological terms as a need to reduce the build-up of thermolabile metabolic intermediates that would be susceptible to destruction by heat. A detailed structural comparison with TIMs from organisms with growth optima ranging from 15 degrees C to 100 degrees C emphasizes the importance in hyperthermophilic proteins of the specific location of ionic interactions for thermal stability rather than their numbers, and shows a clear correlation between the reduction of heat-labile, surface-exposed Asn and Gln residues with thermoadaptation. The comparison confirms the increase in charged surface-exposed residues at the expense of polar residues.
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Affiliation(s)
- Helen Walden
- Centre for Biomolecular Sciences, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK
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19
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Yu J, Yu X, Liu J. A thermostable manganese-containing superoxide dismutase from pathogenChlamydia pneumoniae. FEBS Lett 2004; 562:22-6. [PMID: 15043996 DOI: 10.1016/s0014-5793(04)00170-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Revised: 02/02/2004] [Accepted: 02/02/2004] [Indexed: 11/26/2022]
Abstract
The gene CP0718 encoding a putative manganese-containing superoxide dismutase of Chlamydia pneumoniae AR39 was cloned and expressed in Escherichia coli. Characterization showed that the expressed protein with a monomeric molecular mass of 23.1 kDa had superoxide dismutase (SOD) activity and the cofactor of CpSOD was a bivalent manganese cation. It is unexpected that this enzyme was hyperthermostable, and maintained about 90% activity after incubation at 70 degrees C for 60 min. Manganese binding residues found in the SOD sequences from different species are conserved in CpSOD. Bioinformatics analysis compared with Propionibacterium shermanii MnSOD was performed to elucidate the CpSOD hyperthermostability based on amino acid sequences.
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Affiliation(s)
- Jing Yu
- College of Life Sciences and Technology, Shanghai Jiaotong University, 1954 Hua-shan Road, Shanghai 200030, PR China
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20
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Vieille C, Krishnamurthy H, Hyun HH, Savchenko A, Yan H, Zeikus JG. Thermotoga neapolitana adenylate kinase is highly active at 30 degrees C. Biochem J 2003; 372:577-85. [PMID: 12625835 PMCID: PMC1223421 DOI: 10.1042/bj20021377] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2002] [Revised: 02/18/2003] [Accepted: 03/07/2003] [Indexed: 11/17/2022]
Abstract
The adenylate kinase (AK) gene from Thermotoga neapolitana, a hyperthermophilic bacterium, was cloned and overexpressed in Escherichia coli, and the recombinant enzyme was biochemically characterized. The T. neapolitana AK (TNAK) sequence indicates that this enzyme belongs to the long bacterial AKs. TNAK contains the four cysteine residues that bind Zn(2+) in all Gram-positive AKs and in a few other Zn(2+)-containing bacterial AKs. Atomic emission spectroscopy and titration data indicate a content of 1 mol of Zn(2+)/mol of recombinant TNAK. The EDTA-treated enzyme has a melting temperature (T (m)=93.5 degrees C) 6.2 degrees C below that of the holoenzyme (99.7 degrees C), identifying Zn(2+) as a stabilizing feature in TNAK. TNAK is a monomeric enzyme with a molecular mass of approx. 25 kDa. TNAK displays V (max) and K (m) values at 30 degrees C identical with those of the E. coli AK at 30 degrees C, and displays very high activity at 80 degrees C, with a specific activity above 8000 units/mg. The unusually high activity of TNAK at 30 degrees C makes it an interesting model to test the role of enzyme flexibility in activity.
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Affiliation(s)
- Claire Vieille
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing 48824, USA.
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21
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Purification and characterization of the 3-phosphoglycerate kinase from the thermophile Lactobacillus delbrueckii subsp. lactis. Int Dairy J 2002. [DOI: 10.1016/s0958-6946(02)00069-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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22
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Schramm A, Kohlhoff M, Hensel R. Triose-phosphate isomerase from Pyrococcus woesei and Methanothermus fervidus. Methods Enzymol 2001; 331:62-77. [PMID: 11265484 DOI: 10.1016/s0076-6879(01)31047-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- A Schramm
- Universität Essen, Essen 45117, Germany
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23
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Affiliation(s)
- G Crowhurst
- Schools of Chemistry and Biological Sciences, University of Exeter, Exeter EX4 4QD, United Kingdom
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24
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Ogasahara K, Khechinashvili NN, Nakamura M, Yoshimoto T, Yutani K. Thermal stability of pyrrolidone carboxyl peptidases from the hyperthermophilic Archaeon, Pyrococcus furiosus. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:3233-42. [PMID: 11389725 DOI: 10.1046/j.1432-1327.2001.02220.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The temperature adaptation of pyrrolidone carboxyl peptidase (PCP) from a hyperthermophile, Pyrococcus furiosus (Pf PCP), was characterized in the context of an assembly form of the protein which is a homotetramer at neutral pH. The Pf PCP exhibited maximal catalytic activity at 90-95 degrees C and its activity was higher in the temperature range 30-100 degrees C than its counterpart from the mesophilic Bacillus amyloliquefaciens (BaPCP). Thermal stability was monitored by differential scanning calorimetry (DSC). Two clearly separated peaks appeared on the DSC curves for Pf PCP at alkaline and acidic pH. Using the oxidized Pf PCP and two mutant proteins (Pf C188S and Pf C142/188S), it was found that the peaks on the high and low temperature sides of the DSC curve of Pf PCP were produced by the forms with an intersubunit disulfide bridge between the two subunits and without the bridge, respectively, indicating the stabilization effect of intersubunit disulfide bridges. The denaturation temperature (Td) of Pf PCP with intersubunit disulfide bridges was higher by 53 degrees C at pH 9.0 than that of BaPCP. An analysis of the equilibrium ultracentrifugation patterns showed that the tetrameric Pf C142/188S dissociated into dimers with decreasing pH in the acidic region and became monomer subunits at pH 2.5. The heat denaturation of Pf PCP and its two Cys mutants was highly reversible in the dimeric forms, but completely irreversible in the tetrameric form. The Td of Pf C142/188S decreased as the enzyme became dissociated, but the monomeric form of the protein was still folded at pH 2.5, although BaPCP was completely denatured at acidic pH. These results indicate that subunit interaction plays an important role in stabilizing PCP from P. furiosus in addition to the intrinsic enhanced stability of its monomer.
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Affiliation(s)
- K Ogasahara
- Institute for Protein Research, Osaka University, Suita City, Osaka, Japan
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25
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Walden H, Bell GS, Russell RJ, Siebers B, Hensel R, Taylor GL. Tiny TIM: a small, tetrameric, hyperthermostable triosephosphate isomerase. J Mol Biol 2001; 306:745-57. [PMID: 11243785 DOI: 10.1006/jmbi.2000.4433] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Comparative structural studies on proteins derived from organisms with growth optima ranging from 15 to 100 degrees C are beginning to shed light on the mechanisms of protein thermoadaptation. One means of sustaining hyperthermostability is for proteins to exist in higher oligomeric forms than their mesophilic homologues. Triosephosphate isomerase (TIM) is one of the most studied enzymes, whose fold represents one of nature's most common protein architectures. Most TIMs are dimers of approximately 250 amino acid residues per monomer. Here, we report the 2.7 A resolution crystal structure of the extremely thermostable TIM from Pyrococcus woesei, a hyperthermophilic archaeon growing optimally at 100 degrees C, representing the first archaeal TIM structure. P. woesei TIM exists as a tetramer comprising monomers of only 228 amino acid residues. Structural comparisons with other less thermostable TIMs show that although the central beta-barrel is largely conserved, severe pruning of several helices and truncation of some loops give rise to a much more compact monomer in the small hyperthermophilic TIM. The classical TIM dimer formation is conserved in P. woesei TIM. The extreme thermostability of PwTIM appears to be achieved by the creation of a compact tetramer where two classical TIM dimers interact via an extensive hydrophobic interface. The tetramer is formed through largely hydrophobic interactions between some of the pruned helical regions. The equivalent helical regions in less thermostable dimeric TIMs represent regions of high average temperature factor. The PwTIM seems to have removed these regions of potential instability in the formation of the tetramer. This study of PwTIM provides further support for the role of higher oligomerisation states in extreme thermal stabilisation.
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Affiliation(s)
- H Walden
- Centre for Biomolecular Sciences, The University of St Andrews, Fife, KY16 9ST, Scotland
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26
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Vieille C, Zeikus GJ. Hyperthermophilic enzymes: sources, uses, and molecular mechanisms for thermostability. Microbiol Mol Biol Rev 2001; 65:1-43. [PMID: 11238984 PMCID: PMC99017 DOI: 10.1128/mmbr.65.1.1-43.2001] [Citation(s) in RCA: 1392] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enzymes synthesized by hyperthermophiles (bacteria and archaea with optimal growth temperatures of > 80 degrees C), also called hyperthermophilic enzymes, are typically thermostable (i.e., resistant to irreversible inactivation at high temperatures) and are optimally active at high temperatures. These enzymes share the same catalytic mechanisms with their mesophilic counterparts. When cloned and expressed in mesophilic hosts, hyperthermophilic enzymes usually retain their thermal properties, indicating that these properties are genetically encoded. Sequence alignments, amino acid content comparisons, crystal structure comparisons, and mutagenesis experiments indicate that hyperthermophilic enzymes are, indeed, very similar to their mesophilic homologues. No single mechanism is responsible for the remarkable stability of hyperthermophilic enzymes. Increased thermostability must be found, instead, in a small number of highly specific alterations that often do not obey any obvious traffic rules. After briefly discussing the diversity of hyperthermophilic organisms, this review concentrates on the remarkable thermostability of their enzymes. The biochemical and molecular properties of hyperthermophilic enzymes are described. Mechanisms responsible for protein inactivation are reviewed. The molecular mechanisms involved in protein thermostabilization are discussed, including ion pairs, hydrogen bonds, hydrophobic interactions, disulfide bridges, packing, decrease of the entropy of unfolding, and intersubunit interactions. Finally, current uses and potential applications of thermophilic and hyperthermophilic enzymes as research reagents and as catalysts for industrial processes are described.
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Affiliation(s)
- C Vieille
- Biochemistry Department, Michigan State University, East Lansing, Michigan 48824, USA
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27
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Hutchins AM, Holden JF, Adams MW. Phosphoenolpyruvate synthetase from the hyperthermophilic archaeon Pyrococcus furiosus. J Bacteriol 2001; 183:709-15. [PMID: 11133966 PMCID: PMC94928 DOI: 10.1128/jb.183.2.709-715.2001] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Phosphoenolpyruvate synthetase (PpsA) was purified from the hyperthermophilic archaeon Pyrococcus furiosus. This enzyme catalyzes the conversion of pyruvate and ATP to phosphoenolpyruvate (PEP), AMP, and phosphate and is thought to function in gluconeogenesis. PpsA has a subunit molecular mass of 92 kDa and contains one calcium and one phosphorus atom per subunit. The active form has a molecular mass of 690+/-20 kDa and is assumed to be octomeric, while approximately 30% of the protein is purified as a large ( approximately 1.6 MDa) complex that is not active. The apparent K(m) values and catalytic efficiencies for the substrates pyruvate and ATP (at 80 degrees C, pH 8.4) were 0.11 mM and 1.43 x 10(4) mM(-1). s(-1) and 0.39 mM and 3.40 x 10(3) mM(-1) x s(-1), respectively. Maximal activity was measured at pH 9.0 (at 80 degrees C) and at 90 degrees C (at pH 8.4). The enzyme also catalyzed the reverse reaction, but the catalytic efficiency with PEP was very low [k(cat)/K(m) = 32 (mM. s(-1)]. 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 ( approximately 5% 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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Affiliation(s)
- A M Hutchins
- Department of Biochemistry and Molecular Biology and Center for Metalloenzyme Studies, University of Georgia, Athens, Georgia 30602, USA
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28
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Shima S, Thauer RK, Ermler U, Durchschlag H, Tziatzios C, Schubert D. A mutation affecting the association equilibrium of formyltransferase from the hyperthermophilic Methanopyrus kandleri and its influence on the enzyme's activity and thermostability. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:6619-23. [PMID: 11054114 DOI: 10.1046/j.1432-1327.2000.01756.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Formyltransferase from Methanopyrus kandleri is composed of only one type of subunit of molecular mass 32 kDa. The enzyme is in a monomer/dimer/tetramer association equilibrium, the association constant being affected by lyotropic salts. Oligomerization is required for enzyme activity and thermostability. We report here on a subunit interface mutation (R261E) which affects the dimer/tetramer part of the association equilibrium of formyltransferase. With the mutant protein it was shown that tetramerization is not required for activity but is necessary for high thermostability.
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Affiliation(s)
- S Shima
- Max-Planck-Institut für terrestrische Mikrobiologie and Laboratorium für Mikrobiologie des Fachbereichs Biologie der Philipps-Universität, Marburg, Germany.
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29
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Bentahir M, Feller G, Aittaleb M, Lamotte-Brasseur J, Himri T, Chessa JP, Gerday C. Structural, kinetic, and calorimetric characterization of the cold-active phosphoglycerate kinase from the antarctic Pseudomonas sp. TACII18. J Biol Chem 2000; 275:11147-53. [PMID: 10753921 DOI: 10.1074/jbc.275.15.11147] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The gene encoding the phosphoglycerate kinase (PGK) from the Antarctic Pseudomonas sp. TACII18 has been cloned and found to be inserted between the genes encoding for glyceraldhyde-3-phosphate dehydrogenase and fructose aldolase. The His-tagged and the native recombinant PGK from the psychrophilic Pseudomonas were expressed in Escherichia coli. The wild-type and the native recombinant enzymes displayed identical properties, such as a decreased thermostability and a 2-fold higher catalytic efficiency at 25 degrees C when compared with the mesophilic PGK from yeast. These properties, which reflect typical features of cold-adapted enzymes, were strongly altered in the His-tagged recombinant PGK. The structural model of the psychrophilic PGK indicated that a key determinant of its low stability is the reduced number of salt bridges, surface charges, and aromatic interactions when compared with mesophilic and thermophilic PGK. Differential scanning calorimetry of the psychrophilic PGK revealed unusual variations in its conformational stability for the free and substrate-bound forms. In the free form, a heat-labile and a thermostable domain unfold independently. It is proposed that the heat-labile domain acts as a destabilizing domain, providing the required flexibility around the active site for catalysis at low temperatures.
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Affiliation(s)
- M Bentahir
- Laboratoire de Biochimie, Institut de Chimie B6, Université de Liège, Sart-Tilman, B-4000 Liège, Belgium
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30
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Thoma R, Hennig M, Sterner R, Kirschner K. Structure and function of mutationally generated monomers of dimeric phosphoribosylanthranilate isomerase from Thermotoga maritima. Structure 2000; 8:265-76. [PMID: 10745009 DOI: 10.1016/s0969-2126(00)00106-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND Oligomeric proteins may have been selected for in hyperthermophiles because subunit association provides extra stabilization. Phosphoribosylanthranilate isomerase (PRAI) is monomeric and labile in most mesophilic microorganisms, but dimeric and stable in the hyperthermophile Thermotoga maritima (tPRAI). The two subunits of tPRAI are associated back-to-back and are locked together by a hydrophobic loop. The hypothesis that dimerization is important for thermostability has been tested by rationally designing monomeric variants of tPRAI. RESULTS The comparison of tPRAI and PRAI from Escherichia coli (ePRAI) suggested that levelling the nonplanar dimer interface would weaken the association. The deletion of two residues in the loop loosened the dimer. Subsequent filling of the adjacent pocket and the exchange of polar for apolar residues yielded a weakly associating and a nonassociating monomeric variant. Both variants are as active as the parental dimer but far more thermolabile. The thermostability of the weakly associating monomer increased significantly with increasing protein concentration. The X-ray structure of the nonassociating monomer differed from that of the parental subunit only in the restructured interface. The orientation of the original subunits was maintained in a crystal contact between two monomers. CONCLUSIONS tPRAI is dimeric for reasons of stability. The clearly separated responsibilities of the betaalpha loops, which are involved in activity, and the alphabeta loops, which are involved in protein stability, has permitted the evolution of dimers without compromising their activity. The preserved interaction in the crystal contacts suggests the most likely model for dimer evolution.
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Affiliation(s)
- R Thoma
- Abteilung für Biophysikalische Chemie, Biozentrum der Universität Basel, Basel, CH-4056, Switzerland
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31
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Cheng TC, Ramakrishnan V, Chan SI. Purification and characterization of a cobalt-activated carboxypeptidase from the hyperthermophilic archaeon Pyrococcus furiosus. Protein Sci 1999; 8:2474-86. [PMID: 10595552 PMCID: PMC2144183 DOI: 10.1110/ps.8.11.2474] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A novel metallocarboxypeptidase (PfuCP) has been purified to homogeneity from the hyperthermophilic archaeon, Pyrococcus furiosus, with its intended use in C-terminal ladder sequencing of proteins and peptides at elevated temperatures. PfuCP was purified in its inactive state by the addition of ethylenediaminetetraacetic acid (EDTA) and dithiothreitol (DTT) to purification buffers, and the activity was restored by the addition of divalent cobalt (K, = 24 +/- 4 microM at 80 degrees C). The serine protease inhibitor phenylmethylsulfonyl fluoride (PMSF) had no effect on the activity. The molecular mass of monomeric PfuCP is 59 kDa as determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 58 kDa by SDS-PAGE analysis. In solution, PfuCP exists as a homodimer of approximately 128 kDa as determined by gel filtration chromatography. The activity of PfuCP exhibits a temperature optimum exceeding 90 degrees C under ambient pressure, and a narrow pH optimum of 6.2-6.6. Addition of Co2+ to the apoPfuCP at room temperature does not alter its far-UV circular dichroism (CD) or its intrinsic fluorescence spectrum. Even when the CoPfuCP is heated to 80 degrees C, its far-UV CD shows a minimal change in the global conformation and the intrinsic fluorescence of aromatic residues shows only a partial quenching. Changes in the intrinsic fluorescence appear essentially reversible with temperature. Finally, the far-UV CD and intrinsic fluorescence data suggest that the overall structure of the holoenzyme is extremely thermostable. However, the activities of both the apo and holo enzyme exhibit a similar second-order decay over time, with 50% activity remaining after approximately 40 min at 80 degrees C. The N-blocked synthetic dipeptide, N-carbobenzoxy-Ala-Arg (ZAR), was used in the purification assay. The kinetic parameters at 80 degrees C with 0.4 mM CoCl2 were: Km, 0.9 +/- 0.1 mM; Vmax, 2,300 +/- 70 U mg(-1); and turn over number, 600 +/- 20 s(-1). Activity against other ZAX substrates (X = V, L, I, M, W, Y, F, N, A, S, H, K) revealed a broad specificity for neutral, aromatic, polar, and basic C-terminal residues. This broad specificity was confirmed by the C-terminal ladder sequencing of several synthetic and natural peptides, including porcine N-acetyl-renin substrate, for which we have observed (by MALDI-TOF MS) stepwise hydrolysis by PfuCP of up to seven residues from the C-terminus: Ac-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser.
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Affiliation(s)
- T C Cheng
- Noyes Laboratories, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA
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32
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McHarg J, Kelly SM, Price NC, Cooper A, Littlechild JA. Site-directed mutagenesis of proline 204 in the 'hinge' region of yeast phosphoglycerate kinase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 259:939-45. [PMID: 10092885 DOI: 10.1046/j.1432-1327.1999.00133.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Site-specific mutants have been produced in order to investigate the role of proline 204 in the 'hinge' region of yeast phosphoglycerate kinase (PGK). This totally conserved proline has been shown to be the only cis-proline in the high resolution crystal structures of yeast, B. stearothermophilus, T. brucei and T. maritima PGK, and may therefore have a role in the independent folding of the two domains or in the 'hinge' bending of the molecule during catalysis. The residue was replaced by a histidine (Pro204His) and a phenylalanine (Pro204Phe), and the resulting proteins characterised by differential scanning calorimetry (DSC), circular dichroism (CD), tryptophan fluorescence emission and kinetic analysis. Although the secondary and tertiary structure of the Pro204His protein is generally similar to that of the wild-type enzyme as assessed by CD, the enzyme is less stable to heat and guanidinium chloride denaturation than the wild-type. In the denaturation experiments two transitions were observed for both the wild-type and the Pro204His mutant, as have been previously reported for yeast PGK [Missiakas, D., Betton, J.M., Minard, P. & Yon, J.M. (1990) Biochemistry 29, 8683-8689]. The first transition is accompanied by an increase in fluorescence intensity leading to a hyperfluorescent state, followed by the second, corresponding to a decrease in fluorescence intensity. However, for the Pro204His mutant, the first transition proceeded at lower concentrations of guanidinium chloride and the second transition proceeded to the same extent as for the wild-type protein, suggesting that sequence-distant interactions are more rapidly disrupted in this mutant enzyme than in the wild-type enzyme, while sequence-local interactions are disrupted in a similar way. The Michaelis constants (K(m)) for both 3-phospho-D-glycerate and ATP are increased only by three or fourfold, which confirms that, as expected, the substrate binding sites are largely unaffected by the mutation. However, the turnover and efficiency of the Pro204His mutant is severely impaired, indicating that the mechanism of 'hinge' bending is hindered. The Pro204Phe enzyme was shown to be significantly less well folded than the wild-type and Pro204His enzymes, with considerable loss of both secondary and tertiary structure. It is proposed that the proline residue at 204 in the 'hinge' region of PGK plays a role in the stability and catalytic mechanism of the enzyme.
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Affiliation(s)
- J McHarg
- School of Chemistry, University of Exeter, UK
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33
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Abstract
Three complete genome sequences of thermophilic bacteria provide a wealth of information challenging current ideas concerning phylogeny and evolution, as well as the determinants of protein stability. Considering known protein structures from extremophiles, it becomes clear that no general conclusions can be drawn regarding adaptive mechanisms to extremes of physical conditions. Proteins are individuals that accumulate increments of stabilization; in thermophiles these come from charge clusters, networks of hydrogen bonds, optimization of packing and hydrophobic interactions, each in its own way. Recent examples indicate ways for the rational design of ultrastable proteins.
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Affiliation(s)
- R Jaenicke
- Institute of Biophysics and Physical Biochemistry University of Regensburg D-93040 Regensburg Germany. rainer.jaenicke@biologie. uni-regensburg.de
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34
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Matussek K, Moritz P, Brunner N, Eckerskorn C, Hensel R. Cloning, sequencing, and expression of the gene encoding cyclic 2, 3-diphosphoglycerate synthetase, the key enzyme of cyclic 2, 3-diphosphoglycerate metabolism in Methanothermus fervidus. J Bacteriol 1998; 180:5997-6004. [PMID: 9811660 PMCID: PMC107676 DOI: 10.1128/jb.180.22.5997-6004.1998] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cyclic 2,3-diphosphoglycerate synthetase (cDPGS) catalyzes the synthesis of cyclic 2,3-diphosphoglycerate (cDPG) by formation of an intramolecular phosphoanhydride bond in 2,3-diphosphoglycerate. cDPG is known to be accumulated to high intracellular concentrations (>300 mM) as a putative thermoadapter in some hyperthermophilic methanogens. For the first time, we have purified active cDPGS from a methanogen, the hyperthermophilic archaeon Methanothermus fervidus, sequenced the coding gene, and expressed it in Escherichia coli. cDPGS purification resulted in enzyme preparations containing two isoforms differing in their electrophoretic mobility under denaturing conditions. Since both polypeptides showed the same N-terminal amino acid sequence and Southern analyses indicate the presence of only one gene coding for cDPGS in M. fervidus, the two polypeptides originate from the same gene but differ by a not yet identified modification. The native cDPGS represents a dimer with an apparent molecular mass of 112 kDa and catalyzes the reversible formation of the intramolecular phosphoanhydride bond at the expense of ATP. The enzyme shows a clear preference for the synthetic reaction: the substrate affinity and the Vmax of the synthetic reaction are a factor of 8 to 10 higher than the corresponding values for the reverse reaction. Comparison with the kinetic properties of the electrophoretically homogeneous, apparently unmodified recombinant enzyme from E. coli revealed a twofold-higher Vmax of the enzyme from M. fervidus in the synthesizing direction.
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Affiliation(s)
- K Matussek
- FB 9 Mikrobiologie, Universität GH Essen, D-45117 Essen, Germany
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35
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Hess JM, Tchernajenko V, Vieille C, Zeikus JG, Kelly RM. Thermotoga neapolitana homotetrameric xylose isomerase is expressed as a catalytically active and thermostable dimer in Escherichia coli. Appl Environ Microbiol 1998; 64:2357-60. [PMID: 9647799 PMCID: PMC106395 DOI: 10.1128/aem.64.7.2357-2360.1998] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The xylA gene from Thermotoga neapolitana 5068 was expressed in Escherichia coli. Gel filtration chromatography showed that the recombinant enzyme was both a homodimer and a homotetramer, with the dimer being the more abundant form. The purified native enzyme, however, has been shown to be exclusively tetrameric. The two enzyme forms had comparable stabilities when they were thermoinactivated at 95 degrees C. Differential scanning calorimetry revealed thermal transitions at 99 and 109.5 degrees C for both forms, with an additional shoulder at 91 degrees C for the tetramer. These results suggest that the association of the subunits into the tetrameric form may have little impact on the stability and biocatalytic properties of the enzyme.
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Affiliation(s)
- J M Hess
- Department of Chemical Engineering, North Carolina State University, Raleigh 27695-7905, USA
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36
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Brunner NA, Brinkmann H, Siebers B, Hensel R. NAD+-dependent glyceraldehyde-3-phosphate dehydrogenase from Thermoproteus tenax. The first identified archaeal member of the aldehyde dehydrogenase superfamily is a glycolytic enzyme with unusual regulatory properties. J Biol Chem 1998; 273:6149-56. [PMID: 9497334 DOI: 10.1074/jbc.273.11.6149] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hyperthermophilic archaeum Thermoproteus tenax possesses two glyceraldehyde-3-phosphate dehydrogenases differing in cosubstrate specificity and phosphate dependence of the catalyzed reaction. NAD+-dependent glyceraldehyde-3-phosphate dehydrogenase catalyzes the phosphate-independent irreversible oxidation of D-glyceraldehyde 3-phosphate to 3-phosphoglycerate. The coding gene was cloned, sequenced, and expressed in Escherichia coli. Sequence comparisons showed no similarity to phosphorylating glyceraldehyde-3-phosphate dehydrogenases but revealed a relationship to aldehyde dehydrogenases, with the highest similarity to the subgroup of nonphosphorylating glyceraldehyde-3-phosphate dehydrogenases. The activity of the enzyme is affected by a series of metabolites. All effectors tested influence the affinity of the enzyme for its cosubstrate NAD+. Whereas NADP(H), NADH, and ATP reduce the affinity for the cosubstrate, AMP, ADP, glucose 1-phosphate, and fructose 6-phosphate increase the affinity for NAD+. Additionally, most of the effectors investigated induce cooperativity of NAD+ binding. The irreversible catabolic oxidation of glyceraldehyde 3-phosphate, the control of the enzyme by energy charge of the cell, and the regulation by intermediates of glycolysis and glucan degradation identify the NAD+-dependent glyceraldehyde-3-phosphate dehydrogenase as an integral constituent of glycolysis in T. tenax. Its regulatory properties substitute for those lacking in the reversible nonregulated pyrophosphate-dependent phosphofructokinase in this variant of the Embden-Meyerhof-Parnas pathway.
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Affiliation(s)
- N A Brunner
- Department of Microbiology, FB 9, Universit¿t-GH Essen, Universit¿tsstrasse 5, 45117 Essen, Germany
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37
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Van den Burg B, Vriend G, Veltman OR, Venema G, Eijsink VG. Engineering an enzyme to resist boiling. Proc Natl Acad Sci U S A 1998; 95:2056-60. [PMID: 9482837 PMCID: PMC19247 DOI: 10.1073/pnas.95.5.2056] [Citation(s) in RCA: 222] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In recent years, many efforts have been made to isolate enzymes from extremophilic organisms in the hope to unravel the structural basis for hyperstability and to obtain hyperstable biocatalysts. Here we show how a moderately stable enzyme (a thermolysin-like protease from Bacillus stearothermophilus, TLP-ste) can be made hyperstable by a limited number of mutations. The mutational strategy included replacing residues in TLP-ste by residues found at equivalent positions in naturally occurring, more thermostable variants, as well as rationally designed mutations. Thus, an extremely stable 8-fold mutant enzyme was obtained that was able to function at 100 degrees C and in the presence of denaturing agents. This 8-fold mutant contained a relatively large number of mutations whose stabilizing effect is generally considered to result from a reduction of the entropy of the unfolded state ("rigidifying" mutations such as Gly --> Ala, Ala --> Pro, and the introduction of a disulfide bridge). Remarkably, whereas hyperstable enzymes isolated from natural sources often have reduced activity at low temperatures, the 8-fold mutant displayed wild-type-like activity at 37 degrees C.
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Affiliation(s)
- B Van den Burg
- Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren The Netherlands.
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38
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Beaucamp N, Hofmann A, Kellerer B, Jaenicke R. Dissection of the gene of the bifunctional PGK-TIM fusion protein from the hyperthermophilic bacterium Thermotoga maritima: design and characterization of the separate triosephosphate isomerase. Protein Sci 1997; 6:2159-65. [PMID: 9336838 PMCID: PMC2143554 DOI: 10.1002/pro.5560061010] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Triosephosphate isomerase (TIM), from the hyperthermophilic bacterium Thermotoga maritima, has been shown to be covalently linked to phosphoglycerate kinase (PGK) forming a bifunctional fusion protein with TIM as the C-terminal portion of the subunits of the tetrameric protein (Schurig et al., EMBO J 14:442-451, 1995). To study the effect of the anomalous state of association on the structure, stability, and function of Thermotoga TIM, the isolated enzyme was cloned and expressed in Escherichia coli, and compared with its wild-type structure in the PGK-TIM fusion protein. After introducing a start codon at the beginning of the tpi open reading frame, the gene was expressed in E.c.BL21(DE3)/ pNBTIM. The nucleotide sequence was confirmed and the protein purified as a functional dimer of 56.5 kDa molecular mass. Spectral analysis, using absorption, fluorescence emission, near- and far-UV circular dichroism spectroscopy were used to compare the separated Thermotoga enzyme with its homologs from mesophiles. The catalytic properties of the enzyme at approximately 80 degrees C are similar to those of its mesophilic counterparts at their respective physiological temperatures, in accordance with the idea that under in vivo conditions enzymes occupy corresponding states. As taken from chaotropic and thermal denaturation transitions, the separated enzyme exhibits high intrinsic stability, with a half-concentration of guanidinium-chloride at 3.8 M, and a denaturation half-time at 80 degrees C of 2 h. Comparing the properties of the TIM portion of the PGK-TIM fusion protein with those of the isolated recombinant TIM, it is found that the fusion of the two enzymes not only enhances the intrinsic stability of TIM but also its catalytic efficiency.
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Affiliation(s)
- N Beaucamp
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany
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39
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Meier B, Parak F, Desideri A, Rotilio G. Comparative stability studies on the iron and manganese forms of the cambialistic superoxide dismutase from Propionibacterium shermanii. FEBS Lett 1997; 414:122-4. [PMID: 9305744 DOI: 10.1016/s0014-5793(97)00960-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The superoxide dismutase of Propionibacterium shermanii shows similar activity with iron and manganese bound at the active site of the protein. On the other hand, the iron form, in comparison to the manganese form, exhibits higher stability towards thermal- and pH-dependent inactivation. Upon inactivation the metal ions are released from the active site. Thus, in comparison to the manganese form, a higher stability of the iron-protein complex might be the triggering reason for this behavior.
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Affiliation(s)
- B Meier
- Fakultät für Physik E17, Technische Universität München, Garching, Germany
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40
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Than ME, Hof P, Huber R, Bourenkov GP, Bartunik HD, Buse G, Soulimane T. Thermus thermophilus cytochrome-c552: A new highly thermostable cytochrome-c structure obtained by MAD phasing. J Mol Biol 1997; 271:629-44. [PMID: 9281430 DOI: 10.1006/jmbi.1997.1181] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The three-dimensional structure of cytochrome-c552 from Thermus thermophilus has been determined by the multiple anomalous dispersion technique using synchrotron radiation and refined to a resolution of 1.28 A. Data collection at 90 K and the recording of three data sets (f'-minimum: 7125 eV, f"-maximum: 7138 eV and reference for scaling: 10,077 eV) resulted in an initial electron density of very high quality at 2.1 A, which was readily interpretable for model building. The model was refined to an R value of 19.1% (Rfree=22.4%) at 1.28 A resolution using a fourth data set collected at a photon energy of 11,810 eV. Comparison of this thermophilic cytochrome with its mesophilic mitochondrial or bacterial counterparts reveals significant structural differences which are discussed with respect to their importance for thermostability and binding between this cytochrome and its corresponding ba3-oxidase. Amino acid sequence similarities to other class I cytochromes are very weak and entirely limited to the region around the CXXCH motif close to the N terminus. The N-terminal two-thirds of cytochrome-c552 cover spatial regions around the heme prosthetic group that are similar to those observed for other cytochromes. The actual secondary structural elements that are responsible for that shielding do not, however, correlate well to other structures. Only the N-terminal helix (containing the heme binding cysteine residues) aligns reasonably well with other class I cytochromes. The most striking differences that distinguish the present structure from all other class I cytochromes is the C-terminal one-third of the molecule that wraps around the remainder of the structure as a stabilizing clamp, the existence of an extended beta-sheet covering one edge of the heme and the lack of any internal water molecule.
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Affiliation(s)
- M E Than
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18 A, Martinsried, 82152, Germany
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41
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Sterner R, Kleemann GR, Szadkowski H, Lustig A, Hennig M, Kirschner K. Phosphoribosyl anthranilate isomerase from Thermotoga maritima is an extremely stable and active homodimer. Protein Sci 1996; 5:2000-8. [PMID: 8897600 PMCID: PMC2143258 DOI: 10.1002/pro.5560051006] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The metabolism of hyperthermophilic microorganisms can function properly at temperatures close to 100 degrees C. It follows that they are equipped with both thermostable enzymes and mechanisms that handle labile metabolites. We wanted to understand how stable and active phosphoribosyl anthranilate isomerase (tPRAI) from the hyperthermophile Thermotoga maritima is at its optimum growth temperature of 80 degrees C, and how its thermolabile substrate, N-(5'-phosphoribosyl)-anthranilate (PRA), is protected from rapid decomposition. To this end, the trpF gene of T. maritima was expressed heterologously in Escherichia coli and tPRAI was purified. In contrast to most PRAIs from mesophiles, which are monomers with the eightfold beta alpha (or TIM) barrel fold, tPRAI is a homodimer. It is strongly resistant toward inactivation by temperatures up to 95 degrees C, by acidification to pH 3.2, and by proteases in the presence and absence of detergents. tPRAI is about 35-fold more active at its physiologic temperature than is the enzyme from E. coli (ePRAI) at 37 degrees C. This high catalytic efficiency of tPRAI is likely to complete successfully with the rapid spontaneous hydrolysis of PRA at 80 degrees C. Thus, with respect to both stability and function, tPRAI appears well adapted to the extreme habitat of T. maritima. Single crystals of tPRAI have been obtained that are suitable for X-ray analysis at high resolution.
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Affiliation(s)
- R Sterner
- Abteilung für Biophysikalische Chemie, Biozentrum der Universität Basel, Switzerland.
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42
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Dams T, Ostendorp R, Ott M, Rutkat K, Jaenicke R. Tetrameric and octameric lactate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima. Structure and stability of the two active forms. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 240:274-9. [PMID: 8925837 DOI: 10.1111/j.1432-1033.1996.0274h.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Lactate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima has been functionally expressed in Escherichia coli. As shown by gel-permeation chromatography, dynamic light scattering, and ultracentrifugation, the recombinant protein forms homotetrameric and homooctameric assemblies with identical spectral properties and a common subunit molecular mass (35 kDa). Dynamic light scattering and sedimentation equilibrium experiments proved that both species are monodisperse, thus excluding their interconversion in the given ranges of concentration (0.02-50 mg/ml) and temperature (20-80 degrees C). Rechromatography confirms this finding: the octamer does not dissociate at low enzyme concentrations, nor do tetramers dimerize at the given upper limit of concentration. Renaturation of pure tetramers or octamers after preceding guanidine denaturation leads to redistribution of the two species; increased temperature favors octamer formation. Thermal analysis and denaturation by chaotropic agents do not allow the free energies of stabilization of the two forms to be quantified, because heat coagulation and kinetic partitioning between reconstitution and aggregation causes irreversible side reactions. Guanidine denaturation of the octamer leads to a highly cooperative dissociation to tetramers which subsequently dissociate and unfold to yield metastable dimers and, finally, fully unfolded monomers. Evidently, there is no tight coupling of the two tetramers within the stable octameric quaternary structure. Electron microscopy clearly corroborates this conclusion: image processing shows that the dumb-bell-shaped octamer is made up of two tetramers connected via surface contacts without significant changes in the dimensions of the constituent parts.
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Affiliation(s)
- T Dams
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany
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43
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Abstract
Triosephosphate isomerase (TIM) of the hyperthermophilic Archaea Pyrococcus woesei and Methanothermus fervidus have been purified to homogeneity. The enzymes from the two hyperthermophiles represent homo-tetramers of 100 kDa, contrary to all known bacterial and eukaryotic TIMs, which are dimers of 48-60 kDa. Molecular size determination of the TIM from the mesophilic methanogen Methanobacterium bryantii yielded the usual molecular mass of only 57 kDa, indicating that the tetrameric aggregation state does not represent an archaeal feature but rather correlates with thermoadaptation. A similar preference for higher protein aggregates in hyperthermophilic Archaea has previously been demonstrated for 3-phosphoglycerate kinases. The gene of the P. woesei TIM was cloned and sequenced. The archaeal TIM proved to be homologous to its bacterial and eukaryotic pendants. Most strikingly, the deduced protein sequence comprises only 224 residues and thus represents the shortest TIM sequence known as yet. Taking the three-dimensional structure of the eucaryal TIM as a basis, from the shortenings of the chain considerable rearrangements at the bottom of the alpha/beta barrel and at its functionally inactive flank are expected, which are interpreted in terms of the formation of new subunit contacts.
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Affiliation(s)
- M Kohlhoff
- FB 9 Mikrobiologie, Universität Essen, Germany
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44
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Three Extremely Thermostable Proteins fromSulfolobusand a Reappraisal off he ‘Traffic Rules’. ACTA ACUST UNITED AC 1996. [DOI: 10.1515/bchm3.1996.377.7-8.505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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