1
|
Fujino Y, Goda S, Suematsu Y, Doi K. Development of a new gene expression vector for Thermus thermophilus using a silica-inducible promoter. Microb Cell Fact 2020; 19:126. [PMID: 32513169 PMCID: PMC7282064 DOI: 10.1186/s12934-020-01385-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/01/2020] [Indexed: 01/30/2023] Open
Abstract
Background Thermostable enzymes are commonly produced in mesophilic hosts for research and bioengineering purposes. However, these hosts do not overexpress the active forms of some biologically functional thermoenzymes. Therefore, an efficient thermophilic expression system is needed. Thermus thermophilus contains an easily manipulable genome and is therefore among the best candidate microbes for a “hot” expression system. We previously identified a strong and inducible promoter that was active in T. thermophilus under supersaturated silica conditions. Here, we report a new heterologous gene expression system based on a silica-inducible promoter in T. thermophilus. Results A Thermus sp. A4 gene encoding thermostable β-galactosidase was cloned as a reporter gene into the expression vector pSix1, which contains a selection marker that confers thermostable resistance to hygromycin and a 600 bp DNA region containing a putative silica-inducible promoter. β-galactosidase activity was 11-fold higher in the presence than in the absence of 10 mM silicic acid. SDS-PAGE revealed a prominent band corresponding to 73 kDa of β-galactosidase, and this enzyme was expressed as an active and soluble protein (yield: 27 mg/L) in Thermus but as an inclusion body in Escherichia coli. Truncation of the putative silica-inducible promoter region in Thermus expression vector improved the yield of the target protein, possibly by avoiding plasmid instability due to homologous recombination. Finally, we developed an expression vector containing the pSix1 backbone and a 100 bp DNA region corresponding to the silica-inducible promoter. We used this vector to successfully express the active form of glutamate dehydrogenase from Pyrobaculum islandicum (PisGDH) without additional treatment (yield: 9.5 mg/L), whereas the expression of active PisGDH in E. coli required heat treatment. Conclusion We successfully expressed the thermostable β-galactosidase and PisGDH in T. thermophilus as active and soluble forms and achieved with our system the highest known protein expression levels in this species. These thermoenzymes were expressed in active and soluble forms. Our results validate the use of our silica-inducible expression system as a novel strategy for the intracellular overexpression of thermostable proteins.
Collapse
Affiliation(s)
- Yasuhiro Fujino
- Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Shuichiro Goda
- Graduate School of Science and Engineering, Soka University, 1-236, Tangi-cho, Hachioji-shi, Tokyo, 192-8577, Japan
| | - Yuri Suematsu
- Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Katsumi Doi
- Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
| |
Collapse
|
2
|
Brzezinski K, Czyrko J, Sliwiak J, Nalewajko-Sieliwoniuk E, Jaskolski M, Nocek B, Dauter Z. S-adenosyl-L-homocysteine hydrolase from a hyperthermophile (Thermotoga maritima) is expressed in Escherichia coli in inactive form - Biochemical and structural studies. Int J Biol Macromol 2017; 104:584-596. [PMID: 28629859 PMCID: PMC7888557 DOI: 10.1016/j.ijbiomac.2017.06.065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/12/2017] [Accepted: 06/13/2017] [Indexed: 11/26/2022]
Abstract
Thermotoga maritima is a hyperthermophilic bacterium but its genome encodes a number of archaeal proteins including S-adenosyl-L-homocysteine hydrolase (SAHase), which regulates cellular methylation reactions. The question of proper folding and activity of proteins of extremophilic origin is an intriguing problem. When expressed in E.coli and purified (as a homotetramer) at room temperature, the hyperthermophilic SAHase from T.maritima was inactive. ITC study indicated that the protein undergoes heat-induced conformational changes, and enzymatic activity assays demonstrated that these changes are required to attain enzymatic activity. To explain the mechanism of thermal activation, two crystal structures of the inactive form of T. maritima SAHase (iTmSAHase) were determined for an incomplete binary complex with the reduced cofactor (NADH), and in a mixture of binary complexes with NADH and with adenosine. In contrast to active SAHases, in iTmSAHase only two of the four subunits contain a bound cofactor, predominantly in its non-reactive, reduced state. Moreover, the closed-like conformation of the cofactor-containing subunits precludes substrate delivery to the active site. The two other subunits cannot be involved in the enzymatic reaction either; although they have an open-like conformation, they do not contain the cofactor, whose binding site may be occupied by an adenosine molecule. The results suggest that this enzyme, when expressed in mesophilic cells, is arrested in the activity-incompatible conformation revealed by its crystal structures.
Collapse
Affiliation(s)
- Krzysztof Brzezinski
- Institute of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok, Poland.
| | - Justyna Czyrko
- Institute of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok, Poland
| | - Joanna Sliwiak
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | | | - Mariusz Jaskolski
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland; Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Umultowska 89b, 61-614 Poznan, Poland
| | - Boguslaw Nocek
- Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Zbigniew Dauter
- Synchrotron Radiation Research Section, MCL, National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439, USA
| |
Collapse
|
3
|
Stark H, Wolf J, Albersmeier A, Pham TK, Hofmann JD, Siebers B, Kalinowski J, Wright PC, Neumann-Schaal M, Schomburg D. Oxidative Stickland reactions in an obligate aerobic organism - amino acid catabolism in the Crenarchaeon Sulfolobus solfataricus. FEBS J 2017; 284:2078-2095. [PMID: 28497654 DOI: 10.1111/febs.14105] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/27/2017] [Accepted: 05/08/2017] [Indexed: 11/28/2022]
Abstract
The thermoacidophilic Crenarchaeon Sulfolobus solfataricus is a model organism for archaeal adaptation to extreme environments and renowned for its ability to degrade a broad variety of substrates. It has been well characterised concerning the utilisation of numerous carbohydrates as carbon source. However, its amino acid metabolism, especially the degradation of single amino acids, is not as well understood. In this work, we performed metabolic modelling as well as metabolome, transcriptome and proteome analysis on cells grown on caseinhydrolysate as carbon source in order to draw a comprehensive picture of amino acid metabolism in S. solfataricus P2. We found that 10 out of 16 detectable amino acids are imported from the growth medium. Overall, uptake of glutamate, methionine, leucine, phenylalanine and isoleucine was the highest of all observed amino acids. Our simulations predict an incomplete degradation of leucine and tyrosine to organic acids, and in accordance with this, we detected the export of branched-chain and aromatic organic acids as well as amino acids, ammonium and trehalose into the culture supernatants. The branched-chain amino acids as well as phenylalanine and tyrosine are degraded to organic acids via oxidative Stickland reactions. Such reactions are known for prokaryotes capable of anaerobic growth, but so far have never been observed in an obligate aerobe. Also, 3-methyl-2-butenoate and 2-methyl-2-butenoate are for the first time found as products of modified Stickland reactions for the degradation of branched-chain amino acids. This work presents the first detailed description of branched-chain and aromatic amino acid catabolism in S. solfataricus.
Collapse
Affiliation(s)
- Helge Stark
- Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Germany
| | - Jacqueline Wolf
- Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Germany
| | | | - Trong K Pham
- Departement of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, UK
| | - Julia D Hofmann
- Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Germany
| | - Bettina Siebers
- Molecular Enzyme Technology and Biochemistry, Biofilm Centre, Universität Duisburg-Essen, Germany
| | - Jörn Kalinowski
- Center for Biotechnology - CeBiTec, Universität Bielefeld, Germany
| | - Phillip C Wright
- Departement of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, UK
| | - Meina Neumann-Schaal
- Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Germany
| | - Dietmar Schomburg
- Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Germany
| |
Collapse
|
4
|
Fifteen novel immunoreactive proteins of Chinese virulent Haemophilus parasuis serotype 5 verified by an immunoproteomic assay. Folia Microbiol (Praha) 2014; 60:81-7. [PMID: 25200063 DOI: 10.1007/s12223-014-0343-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 08/25/2014] [Indexed: 11/27/2022]
Abstract
Haemophilus parasuis (H. parasuis) is associated with meningitis, polyserositis, polyarthritis and bacterial pneumonia. At present, its prevention and control is difficult because of the lack of suitable subunit vaccines. Nowadays, high-throughput methods, immunoproteomics, are available to screen for more vaccine candidates. A protein extraction method for H. parasuis and two-dimensional electrophoresis (2-DE) were optimized to provide high-resolution profiles covering pH 3 to 10. Twenty immunoreactive spots were excised from gels after strict comparison between 2-DE Western blot membranes and the relevant gels. Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and MALDI-TOF-TOF-MS successfully identified 16 different proteins. Fifteen of them were reported as immunoreactive proteins in H. parasuis for the first time. In addition, recombinant HP5-7 (ABC transporter, periplasmic-binding protein) showed immunoreactivity both with hyperimmune rabbit serum and convalescent swine serum. Four recombinants of the 14 successfully expressed genes showed immunoreactivity with hyperimmune rabbit serum.
Collapse
|
5
|
Yi Z, Su X, Revindran V, Mackie RI, Cann I. Molecular and biochemical analyses of CbCel9A/Cel48A, a highly secreted multi-modular cellulase by Caldicellulosiruptor bescii during growth on crystalline cellulose. PLoS One 2013; 8:e84172. [PMID: 24358340 PMCID: PMC3865294 DOI: 10.1371/journal.pone.0084172] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 11/20/2013] [Indexed: 01/24/2023] Open
Abstract
During growth on crystalline cellulose, the thermophilic bacterium Caldicellulosiruptor bescii secretes several cellulose-degrading enzymes. Among these enzymes is CelA (CbCel9A/Cel48A), which is reported as the most highly secreted cellulolytic enzyme in this bacterium. CbCel9A/Cel48A is a large multi-modular polypeptide, composed of an N-terminal catalytic glycoside hydrolase family 9 (GH9) module and a C-terminal GH48 catalytic module that are separated by a family 3c carbohydrate-binding module (CBM3c) and two identical CBM3bs. The wild-type CbCel9A/Cel48A and its truncational mutants were expressed in Bacillus megaterium and Escherichia coli, respectively. The wild-type polypeptide released twice the amount of glucose equivalents from Avicel than its truncational mutant that lacks the GH48 catalytic module. The truncational mutant harboring the GH9 module and the CBM3c was more thermostable than the wild-type protein, likely due to its compact structure. The main hydrolytic activity was present in the GH9 catalytic module, while the truncational mutant containing the GH48 module and the three CBMs was ineffective in degradation of either crystalline or amorphous cellulose. Interestingly, the GH9 and/or GH48 catalytic modules containing the CBM3bs form low-density particles during hydrolysis of crystalline cellulose. Moreover, TM3 (GH9/CBM3c) and TM2 (GH48 with three CBM3 modules) synergistically hydrolyze crystalline cellulose. Deletion of the CBM3bs or mutations that compromised their binding activity suggested that these CBMs are important during hydrolysis of crystalline cellulose. In agreement with this observation, seven of nine genes in a C. bescii gene cluster predicted to encode cellulose-degrading enzymes harbor CBM3bs. Based on our results, we hypothesize that C. bescii uses the GH48 module and the CBM3bs in CbCel9A/Cel48A to destabilize certain regions of crystalline cellulose for attack by the highly active GH9 module and other endoglucanases produced by this hyperthermophilic bacterium.
Collapse
Affiliation(s)
- Zhuolin Yi
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Xiaoyun Su
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Vanessa Revindran
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Roderick I. Mackie
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Isaac Cann
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
| |
Collapse
|
6
|
Polysaccharide-degrading thermophiles generated by heterologous gene expression in Geobacillus kaustophilus HTA426. Appl Environ Microbiol 2013; 79:5151-8. [PMID: 23793634 DOI: 10.1128/aem.01506-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Thermophiles have important advantages over mesophiles as host organisms for high-temperature bioprocesses, functional production of thermostable enzymes, and efficient expression of enzymatic activities in vivo. To capitalize on these advantages of thermophiles, we describe here a new inducible gene expression system in the thermophile Geobacillus kaustophilus HTA426. Six promoter regions in the HTA426 genome were identified and analyzed for expression profiles using β-galactosidase reporter assay. This analysis identified a promoter region upstream of a putative amylose-metabolizing gene cluster that directed high-level expression of the reporter gene. The expression was >280-fold that without a promoter and was further enhanced 12-fold by maltose addition. In association with a multicopy plasmid, this promoter region was used to express heterologous genes. Several genes, including a gene whose product was insoluble when expressed in Escherichia coli, were successfully expressed as soluble proteins, with yields of 0.16 to 59 mg/liter, and conferred new functions to G. kaustophilus strains. Remarkably, cellulase and α-amylase genes conferred the ability to degrade cellulose paper and insoluble starch at high temperatures, respectively, generating thermophiles with the potential to degrade plant biomass. Our results demonstrate that this novel expression system expands the potential applications of G. kaustophilus.
Collapse
|
7
|
Ohtani N, Tomita M, Itaya M. Identification of a replication initiation protein of the pVV8 plasmid from Thermus thermophilus HB8. Extremophiles 2012; 17:15-28. [PMID: 23114983 DOI: 10.1007/s00792-012-0489-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 10/09/2012] [Indexed: 11/29/2022]
Abstract
Recently, the extremely thermophilic bacterium Thermus thermophilus HB8 has been demonstrated to harbor a circular plasmid designated by pVV8 in addition to two well-known plasmids, pTT8 and pTT27, and its entire sequence has been determined. The absence of any obvious replication initiation gene in the 81.2 kb plasmid prompted us to isolate its minimum replicon. By in vivo replication assays with fragments deleted in a stepwise manner, a minimum replicon containing a single ORF, TTHV001, was identified. A protein encoded by TTHV001 showed no amino acid sequence similarity to other function-known proteins. As the results of in vivo and in vitro experiments strongly suggested that the TTHV001 protein was involved in the replication initiation of pVV8, the protein and the gene were referred to as RepV and repV, respectively. The RepV protein binds to an inverted repeat sequence within its own repV gene and then triggers the unwinding of the DNA duplex in an A + T-rich region located just downstream from the inverted repeat. The in vivo replication assays with minimum replicon mutants in the RepV binding site or the unwinding region demonstrated that the unwinding in the region by the RepV binding was essential for pVV8 replication initiation.
Collapse
Affiliation(s)
- Naoto Ohtani
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan.
| | | | | |
Collapse
|
8
|
Structural characteristics of active and inactive glutamate dehydrogenases from the hyperthermophile Pyrobaculum islandicum. Biosci Biotechnol Biochem 2012; 76:1601-10. [PMID: 22972344 DOI: 10.1271/bbb.120367] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The enzymes from hyperthermophiles are generally extremely thermostable and lose little or no activity during long periods under a variety conditions. This high stability is very attractive, in that it gives the enzymes potential for use in numerous bioprocesses. My research group has investigated this high stability from the viewpoint of the relationship between function and structure. In this review, I describe the molecular mechanism underlying the extreme stability of unboiled NAD-dependent glutamate dehydrogenase from the hyperthermophile Pyrobaculum islandicum. I also describe the activation of the inactive recombinant enzyme produced in mesophilic Escherichia coli from the viewpoint of the relationship between structure and activity.
Collapse
|
9
|
Ozawa Y, Siddiqui MA, Takahashi Y, Urushiyama A, Ohmori D, Yamakura F, Arisaka F, Imai T. Indolepyruvate ferredoxin oxidoreductase: An oxygen-sensitive iron-sulfur enzyme from the hyperthermophilic archaeon Thermococcus profundus. J Biosci Bioeng 2012; 114:23-7. [PMID: 22608551 DOI: 10.1016/j.jbiosc.2012.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 02/08/2012] [Accepted: 02/15/2012] [Indexed: 10/28/2022]
Abstract
Thermococcus profundus is a strictly anaerobic sulfur-dependent archaeon that grows optimally at 80°C by peptide fermentation. Indolepyruvate ferredoxin oxidoreductase (IOR), an enzyme involved in the peptide fermentation pathway, was purified to homogeneity from the archaeon under strictly anaerobic conditions. The maximal activity was obtained above the boiling temperature of water (105°C), with a half-life of 62min at 100°C and 20min at 105°C. IOR was oxygen-sensitive with a half-life of 7h at 25°C under aerobic conditions. The specific activity of T. profundus IOR was found to be dependent on the number of [4Fe-4S] clusters in the enzyme.
Collapse
Affiliation(s)
- Yukiko Ozawa
- Department of Life Science and Graduate School of Life Science, Rikkyo (St. Paul's) University, Toshima-ku, Tokyo 171-8501, Japan
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Genetic analysis of the upper phenylacetate catabolic pathway in the production of tropodithietic acid by Phaeobacter gallaeciensis. Appl Environ Microbiol 2012; 78:3539-51. [PMID: 22407685 DOI: 10.1128/aem.07657-11] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Production of the antibiotic tropodithietic acid (TDA) depends on the central phenylacetate catabolic pathway, specifically on the oxygenase PaaABCDE, which catalyzes epoxidation of phenylacetyl-coenzyme A (CoA). Our study was focused on genes of the upper part of this pathway leading to phenylacetyl-CoA as precursor for TDA. Phaeobacter gallaeciensis DSM 17395 encodes two genes with homology to phenylacetyl-CoA ligases (paaK1 and paaK2), which were shown to be essential for phenylacetate catabolism but not for TDA biosynthesis and phenylalanine degradation. Thus, in P. gallaeciensis another enzyme must produce phenylacetyl-CoA from phenylalanine. Using random transposon insertion mutagenesis of a paaK1-paaK2 double mutant we identified a gene (ior1) with similarity to iorA and iorB in archaea, encoding an indolepyruvate:ferredoxin oxidoreductase (IOR). The ior1 mutant was unable to grow on phenylalanine, and production of TDA was significantly reduced compared to the wild-type level (60%). Nuclear magnetic resonance (NMR) spectroscopic investigations using (13)C-labeled phenylalanine isotopomers demonstrated that phenylalanine is transformed into phenylacetyl-CoA by Ior1. Using quantitative real-time PCR, we could show that expression of ior1 depends on the adjacent regulator IorR. Growth on phenylalanine promotes production of TDA, induces expression of ior1 (27-fold) and paaK1 (61-fold), and regulates the production of TDA. Phylogenetic analysis showed that the aerobic type of IOR as found in many roseobacters is common within a number of different phylogenetic groups of aerobic bacteria such as Burkholderia, Cupriavidis, and Rhizobia, where it may also contribute to the degradation of phenylalanine.
Collapse
|
11
|
Nguyen PQ, Silberg JJ. A selection that reports on protein-protein interactions within a thermophilic bacterium. Protein Eng Des Sel 2010; 23:529-36. [PMID: 20418388 DOI: 10.1093/protein/gzq024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many proteins can be split into fragments that exhibit enhanced function upon fusion to interacting proteins. While this strategy has been widely used to create protein-fragment complementation assays (PCAs) for discovering protein-protein interactions within mesophilic organisms, similar assays have not yet been developed for studying natural and engineered protein complexes at the temperatures where thermophilic microbes grow. We describe the development of a selection for protein-protein interactions within Thermus thermophilus that is based upon growth complementation by fragments of Thermotoga neapolitana adenylate kinase (AK(Tn)). Complementation studies with an engineered thermophile (PQN1) that is not viable above 75 degrees C because its adk gene has been replaced by a Geobacillus stearothermophilus ortholog revealed that growth could be restored at 78 degrees C by a vector that coexpresses polypeptides corresponding to residues 1-79 and 80-220 of AK(Tn). In contrast, PQN1 growth was not complemented by AK(Tn) fragments harboring a C156A mutation within the zinc-binding tetracysteine motif unless these fragments were fused to Thermotoga maritima chemotaxis proteins that heterodimerize (CheA and CheY) or homodimerize (CheX). This enhanced complementation is interpreted as arising from chemotaxis protein-protein interactions, since AK(Tn)-C156A fragments having only one polypeptide fused to a chemotaxis protein did not complement PQN1 to the same extent. This selection increases the maximum temperature where a PCA can be used to engineer thermostable protein complexes and to map protein-protein interactions.
Collapse
Affiliation(s)
- Peter Q Nguyen
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251, USA
| | | |
Collapse
|
12
|
Expression Profiles and Physiological Roles of Two Types of Prefoldins from the Hyperthermophilic Archaeon Thermococcus kodakaraensis. J Mol Biol 2008; 382:298-311. [DOI: 10.1016/j.jmb.2008.07.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 07/11/2008] [Accepted: 07/14/2008] [Indexed: 11/21/2022]
|
13
|
Lee MH, Yang SJ, Kim JW, Lee HS, Kim JW, Park KH. Characterization of a thermostable cyclodextrin glucanotransferase from Pyrococcus furiosus DSM3638. Extremophiles 2007; 11:537-41. [PMID: 17308866 DOI: 10.1007/s00792-007-0061-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2006] [Accepted: 12/10/2006] [Indexed: 10/23/2022]
Abstract
A gene that encodes the enzyme Pyrococcus furiosus cyclodextrin glucanotransferase (PFCGT) was cloned in Escherichia coli. PFCGT was highly expressed in recombinant E. coli after compensation for codon usage bias using the pRARE plasmid. Purified PFCGT was extremely thermostable with an optimal temperature and pH of 95 degrees C and 5.0, respectively, retaining 97% of its activity at 100 degrees C. Incubation at 60 degrees C for 20 min during the purification process led to a 1.5-fold increase in enzymatic activity. A time course assay of the PFCGT reaction with starch indicated that cyclic alpha-1,4-glucans with DPs greater than 20 were produced at the beginning of the incubation followed by an increase in beta-CD. The major final product of PFCGT cyclization was beta-CD, and thus the enzyme is a beta-CGTase.
Collapse
Affiliation(s)
- Myoung-Hee Lee
- Center for Agricultural Biomaterials, and Department of Food Science and Biotechnology, School of Agricultural Biotechnology, Seoul National University, Seoul, 151-921, South Korea
| | | | | | | | | | | |
Collapse
|
14
|
Goda S, Kojima M, Nishikawa Y, Kujo C, Kawakami R, Kuramitsu S, Sakuraba H, Hiragi Y, Ohshima T. Intersubunit interaction induced by subunit rearrangement is essential for the catalytic activity of the hyperthermophilic glutamate dehydrogenase from Pyrobaculum islandicum. Biochemistry 2006; 44:15304-13. [PMID: 16285734 DOI: 10.1021/bi050478l] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The specific activity of recombinant Pyrobaculum islandicum glutamate dehydrogenase (pis-GDH) expressed in Escherichia coli is much lower than that of the native enzyme. However, when the recombinant enzyme is heated at 90 degrees C or exposed to 5 M urea, the activity increases to a level comparable to that of the native enzyme. Small-angle X-ray scattering measurements revealed that the radius of gyration (R(g,z)) of the hexameric recombinant enzyme was reduced to 47 A from 55 A by either heat or urea, and that the final structure of the active enzyme is the same irrespective of the mechanism of activation. Activation was accompanied by a shift in the peaks of the Kratky plot, though the molecular mass of the enzyme was unchanged. The activation-induced decline in R(g,z) followed first-order kinetics, indicating that activation of the enzyme involved a transition between two states, which was confirmed by singular-value decomposition analysis. When the low-resolution structure of the recombinant enzyme was restored using ab initio modeling, we found it to possess no point symmetry, whereas the heat-activated enzyme possessed 32-point symmetry. In addition, a marked increase in the fluorescence emission was observed with addition of ANS to the inactive recombinant enzyme but not the active forms, indicating that upon activation hydrophobic residues on the surface of the recombinant protein moved to the interior. Taken together, these data strongly suggest that subunit rearrangement, i.e., a change in the quaternary structure of the hexameric recombinant pis-GDH, is essential for activation of the enzyme.
Collapse
Affiliation(s)
- Shuichiro Goda
- Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, Minamijosanjimacho, Tokushima 770-8506, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Nishikori S, Shiraki K, Fujiwara S, Imanaka T, Takagi M. Unfolding mechanism of a hyperthermophilic protein O6-methylguanine-DNA methyltransferase. Biophys Chem 2005; 116:97-104. [PMID: 15950821 DOI: 10.1016/j.bpc.2005.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Revised: 03/02/2005] [Accepted: 03/07/2005] [Indexed: 10/25/2022]
Abstract
Unfolding intermediates have been found only rarely in earlier studies, and how a protein unfolds is therefore poorly understood. In this paper, we show experimental evidence for multiple pathways and multiple intermediates during unfolding reaction of O(6)-methylguanine-DNA methyltransferase from hyperthermophile Thermococcus kodakaraensis (Tk-MGMT). The unfolding profiles monitored by far-UV CD and tryptophan fluorescence were both biphasic, and unfolding monitored by fluorescence was faster than that monitored by CD. GdnHCl-induced titration curves indicate that the intermediates with significant alpha-helical structure accumulate during unfolding. Dependence of kinetic phases on initial GdnHCl concentrations and cysteine reactivity of Tk-MGMT were investigated, suggesting that the heterogeneity of native conformations and parallel unfolding pathways.
Collapse
Affiliation(s)
- Shingo Nishikori
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Tatsunokuchi, Ishikawa 923-1292, Japan
| | | | | | | | | |
Collapse
|
16
|
Porat I, Waters BW, Teng Q, Whitman WB. Two biosynthetic pathways for aromatic amino acids in the archaeon Methanococcus maripaludis. J Bacteriol 2004; 186:4940-50. [PMID: 15262931 PMCID: PMC451642 DOI: 10.1128/jb.186.15.4940-4950.2004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methanococcus maripaludis is a strictly anaerobic, methane-producing archaeon. Aromatic amino acids (AroAAs) are biosynthesized in this autotroph either by the de novo pathway, with chorismate as an intermediate, or by the incorporation of exogenous aryl acids via indolepyruvate oxidoreductase (IOR). In order to evaluate the roles of these pathways, the gene that encodes the third step in the de novo pathway, 3-dehydroquinate dehydratase (DHQ), was deleted. This mutant required all three AroAAs for growth, and no DHQ activity was detectible in cell extracts, compared to 6.0 +/- 0.2 mU mg(-1) in the wild-type extract. The growth requirement for the AroAAs could be fulfilled by the corresponding aryl acids phenylacetate, indoleacetate, and p-hydroxyphenylacetate. The specific incorporation of phenylacetate into phenylalanine by the IOR pathway was demonstrated in vivo by labeling with [1-(13)C]phenylacetate. M. maripaludis has two IOR homologs. A deletion mutant for one of these homologs contained 76, 74, and 42% lower activity for phenylpyruvate, p-hydoxyphenylpyruvate, and indolepyruvate oxidation, respectively, than the wild type. Growth of this mutant in minimal medium was inhibited by the aryl acids, but the AroAAs partially restored growth. Genetic complementation of the IOR mutant also restored much of the wild-type phenotype. Thus, aryl acids appear to regulate the expression or activity of the de novo pathway. The aryl acids did not significantly inhibit the activity of the biosynthetic enzymes chorismate mutase, prephenate dehydratase, and prephenate dehydrogenase in cell extracts, so the inhibition of growth was probably not due to an effect on these enzymes.
Collapse
Affiliation(s)
- Iris Porat
- Department of Microbiology, University of Georgia, Athens, GA 30602-2605, USA
| | | | | | | |
Collapse
|
17
|
Izumikawa N, Shiraki K, Nishikori S, Fujiwara S, Imanaka T, Takagi M. Biophysical analysis of heat-induced structural maturation of glutamate dehydrogenase from a hyperthermophilic archaeon. J Biosci Bioeng 2004; 97:305-9. [PMID: 16233634 DOI: 10.1016/s1389-1723(04)70210-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2003] [Accepted: 02/24/2004] [Indexed: 11/23/2022]
Abstract
Tertiary structure of the recombinant glutamate dehydrogenase from Thermococcus kodakaraensis KOD1 (Tk-rGDH) converts into an intact form induced by the heat treatment. This phenomenon, heat-induced structural maturation, means that high temperature plays an important role in the proper folding and oligomerization of Tk-rGDH. In this work, we analyzed the heat-induced structural maturation of Tk-rGDH by differential scanning microcalorimetry (DSC), circular dichroism (CD), and activity measurements. In DSC measurements, the peak of adsorption of non-heated Tk-rGDH (nh-Tk-rGDH) was two times smaller than that of Tk-rGDH heated at 70 degrees C for 30 min (h-Tk-rGDH). The transition temperature (T(m)) of h-Tk-rGDH was 115 degrees C, which was about 3 degrees C higher than that of nh-Tk-rGDH. In the presence of 0.5 M NaCl, the nh-Tk-rGDH showed two peaks at 107 degrees C and 114 degrees C, while the h-Tk-rGDH showed a single peak at 115.7 degrees C. The heat-induced conformational change process was monitored by changes in CD intensity at 222 nm, and the result showed that heat-induced structural maturation is irreversible. The heat treatment at 70 degrees C showed the highest enhancement in activity, which was 15% larger than that of heat-treated Tk-rGDH at 40 degrees C. The results indicate that heat-induced structural maturation involves an irreversible process, transforming the non-heated form to the stable and active form.
Collapse
Affiliation(s)
- Naoshige Izumikawa
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Tatsunokuchi, Ishikawa 923-1292, Japan
| | | | | | | | | | | |
Collapse
|
18
|
|
19
|
Puchkaev AV, Wakagi T, Ortiz de Montellano PR. CYP119 plus a Sulfolobus tokodaii strain 7 ferredoxin and 2-oxoacid:ferredoxin oxidoreductase constitute a high-temperature cytochrome P450 catalytic system. J Am Chem Soc 2002; 124:12682-3. [PMID: 12392414 DOI: 10.1021/ja0282036] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cytochrome P450 superfamily of enzymes catalyzes a broad range of oxidative processes involved in the metabolism of fatty acids, biosynthesis of sterols, and elimination of drugs and xenobiotics. Application of the unique properties of P450 enzymes as fine biocatalysts in biotechnology is limited due to their thermal instability and the requirement for auxiliary electron-donor proteins and cofactors. CYP119, a thermophilic P450 enzyme from Sulfolobus solfataricus, was characterized some time ago, but no high-temperature redox partners have been available for it. Here we report reconstitution of CYP119 with a novel high-temperature electron-donor system consisting of a ferredoxin and 2-oxoacid:ferredoxin oxidoreductase from Sulfolobus tokodaii strain 7 that, unlike all other known P450 electron-donor partners, utilizes coenzyme-A and pyruvic acid rather than NADH or NADPH as the source of electrons. The oxidation of lauric acid by the reconstituted system increased 16-fold as the temperature increased from 25 to 70 degrees C and was functional for more than 30 min at the higher temperature. This first in vitro high-temperature P450 catalytic system is a key step in the development of practical high-temperature monooxygenase systems.
Collapse
Affiliation(s)
- Andrei V Puchkaev
- Department of Pharmaceutical Chemistry, University of California, San Francisco 94143-0446, USA
| | | | | |
Collapse
|
20
|
Thermostable hydantoinase from a hyperthermophilic archaeon, Methanococcus jannaschii. Enzyme Microb Technol 2002. [DOI: 10.1016/s0141-0229(02)00047-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
21
|
FUJIWARA SHINSUKE. Extremophiles: Developments of Their Special Functions and Potential Resources. J Biosci Bioeng 2002. [DOI: 10.1263/jbb.94.518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
22
|
Fukuda E, Kino H, Matsuzawa H, Wakagi T. Role of a highly conserved YPITP motif in 2-oxoacid:ferredoxin oxidoreductase: heterologous expression of the gene from Sulfolobus sp.strain 7, and characterization of the recombinant and variant enzymes. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:5639-46. [PMID: 11683888 DOI: 10.1046/j.1432-1033.2001.02504.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
2-Oxoacid:ferredoxin oxidoreductase from Sulfolobus sp. strain 7, an aerobic and thermoacidophilic crenoarchaeon, catalyses the coenzyme A-dependent oxidative decarboxylation of pyruvate and 2-oxoglutarate, a cognate Zn-7Fe-ferredoxin serving as an electron acceptor. It comprises two subunits, a (632 amino acids) and b (305 amino acids). To further elucidate its structure and function, we constructed a gene expression system. The wild-type recombinant enzyme was indistinguishable from the natural one in every criterion investigated. A series of variants was constructed to elucidate the role of the YPITP-motif (residues 253-257) in subunit a, which is conserved universally in the 2-oxoacid:ferredoxin oxidoreductase (OFOR) family. Single amino-acid replacements at Y253 and P257 by other amino acids caused a drastic loss of enzyme activity. T256, the hydroxyl group of which has been proposed to be essential for binding of the 2-oxo group of the substrate in the Desulfovibrio africanus enzyme, was unexpectedly replaceable with Ala, the kcat and Km for 2-oxoglutarate being approximately 33% and approximately 51%, respectively, as compared with that of the wild-type enzyme. Replacement at other positions resulted in a significant decrease in the kcat of the reaction while the Km for 2-oxoacid was only slightly affected. Thus, the YPITP-motif is essential for the turnover of the reaction rather than the affinity toward 2-oxoacid.
Collapse
Affiliation(s)
- E Fukuda
- Department of Biotechnology, The University of Tokyo, Japan
| | | | | | | |
Collapse
|
23
|
Schut GJ, Menon AL, Adams MW. 2-keto acid oxidoreductases from Pyrococcus furiosus and Thermococcus litoralis. Methods Enzymol 2001; 331:144-58. [PMID: 11265457 DOI: 10.1016/s0076-6879(01)31053-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- G J Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Center for Metalloenzyme Studies, Athens, Georgia 30602-7229, USA
| | | | | |
Collapse
|
24
|
Tang XF, Ezaki S, Atomi H, Imanaka T. Biochemical analysis of a thermostable tryptophan synthase from a hyperthermophilic archaeon. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:6369-77. [PMID: 11029579 DOI: 10.1046/j.1432-1327.2000.01721.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pyridoxal 5'-phosphate-dependent tryptophan synthase catalyzes the last two reactions of tryptophan biosynthesis, and is comprised of two distinct subunits, alpha and beta. TktrpA and TktrpB, which encode the alpha subunit and beta subunit of tryptophan synthase from a hyperthermophilic archaeon, Thermococcus kodakaraensis KOD1, were independently expressed in Escherichia coli and their protein products were purified. Tryptophan synthase complex (Tk-TS complex), obtained by heat treatment of a mixture of the cell-free extracts containing each subunit, was also purified. Gel-filtration chromatography revealed that Tk-TrpA was a monomer (alpha), Tk-TrpB was a dimer (beta2), and Tk-TS complex was a tetramer (alpha2 beta2). The Tk-TS complex catalyzed the overall alphabeta reaction with a specific activity of 110 micromol Trp per micromol active site per min under its optimal conditions (80 degrees C, pH 8.5). Individual activity of the alpha and beta reactions of the Tk-TS complex were 8.5 micromol indole per micromol active site per min (70 degrees C, pH 7.0) and 119 micromol Trp per micromol active site per min (90 degrees C, pH 7.0), respectively. The low activity of the alpha reaction of the Tk-TS complex indicated that turnover of the beta reaction, namely the consumption of indole, was necessary for efficient progression of the alpha reaction. The alpha and beta reaction activities of independently purified Tk-TrpA and Tk-TrpB were 10-fold lower than the respective activities detected from the Tk-TS complex, indicating that during heat treatment, each subunit was necessary for the other to obtain a proper conformation for high enzyme activity. Tk-TrpA showed only trace activities at all temperatures examined (40-85 degrees C). Tk-TrpB also displayed low levels of activity at temperatures below 70 degrees C. However, Tk-TrpB activity increased at temperatures above 70 degrees C, and eventually at 100 degrees C, reached an equivalent level of activity with the beta reaction activity of Tk-TS complex. Taking into account the results of circular dichroism analyses of the three enzymes, a model is proposed which explains the relationship between structure and activity of the alpha and beta subunits with changes in temperature. This is the first report of an archaeal tryptophan synthase, and the first biochemical analysis of a thermostable tryptophan synthase at high temperature.
Collapse
Affiliation(s)
- X F Tang
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, Japan
| | | | | | | |
Collapse
|
25
|
Yamamoto T, Shiraki K, Fujiwara S, Takagi M, Fukui K, Imanaka T. In vitro heat effect on functional and conformational changes of cyclodextrin glucanotransferase from hyperthermophilic archaea. Biochem Biophys Res Commun 1999; 265:57-61. [PMID: 10548490 DOI: 10.1006/bbrc.1999.1629] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The in vitro heat effect on protein characteristics of thermostable enzyme was examined using a cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19) from the hyperthermophilic archaeon Thermococcus sp. B1001 as a model protein. The recombinant form of CGTase was obtained as an inclusion body from Escherichia coli cells harboring a plasmid which carried the B1001 CGTase gene (cgtA). CGTase was solubilized by 6 M urea, refolded, purified to homogeneity, and heat treated at 80 degrees C for 20 min. Enzyme characteristics were examined compared with those of unheated CGTase. Cyclization activity was increased by in vitro heat treatment, while hydrolysis activity was decreased. The heated and unheated CGTases were analyzed for structures by circular dichroism (CD). The near- and far-UV CD spectra indicated that the structure of unheated CGTase with low cyclization activity was different from that of heated CGTase with high activity. Differential scanning calorimetry of unheated CGTase showed two absorption peaks at 87 and 106 degrees C with increasing temperature. After heat treatment, the minor peak at 87 degrees C disappeared, suggesting that heat-dependent structural conversion occurred in CGTase. These results indicate that the thermal environment plays an important role for the protein folding process of thermostable CGTase.
Collapse
Affiliation(s)
- T Yamamoto
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Yamadaoka, Suita, 565-0871, Japan
| | | | | | | | | | | |
Collapse
|
26
|
Musfeldt M, Selig M, Schönheit P. Acetyl coenzyme A synthetase (ADP forming) from the hyperthermophilic Archaeon pyrococcus furiosus: identification, cloning, separate expression of the encoding genes, acdAI and acdBI, in Escherichia coli, and in vitro reconstitution of the active heterotetrameric enzyme from its recombinant subunits. J Bacteriol 1999; 181:5885-8. [PMID: 10482538 PMCID: PMC94117 DOI: 10.1128/jb.181.18.5885-5888.1999] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acetyl-coenzyme A (acetyl-CoA) synthetase (ADP forming) represents a novel enzyme in archaea of acetate formation and energy conservation (acetyl-CoA + ADP + P(i) --> acetate + ATP + CoA). Two isoforms of the enzyme have been purified from the hyperthermophile Pyrococcus furiosus. Isoform I is a heterotetramer (alpha(2)beta(2)) with an apparent molecular mass of 145 kDa, composed of two subunits, alpha and beta, with apparent molecular masses of 47 and 25 kDa, respectively. By using N-terminal amino acid sequences of both subunits, the encoding genes, designated acdAI and acdBI, were identified in the genome of P. furiosus. The genes were separately overexpressed in Escherichia coli, and the recombinant subunits were reconstituted in vitro to the active heterotetrameric enzyme. The purified recombinant enzyme showed molecular and catalytical properties very similar to those shown by acetyl-CoA synthetase (ADP forming) purified from P. furiosus.
Collapse
Affiliation(s)
- M Musfeldt
- Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Am Botanischen Garten 1-9, D-24118 Kiel, Germany
| | | | | |
Collapse
|