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Tratsiak K, Prudnikova T, Drienovska I, Damborsky J, Brynda J, Pachl P, Kuty M, Chaloupkova R, Rezacova P, Kuta Smatanova I. Crystal structure of the cold-adapted haloalkane dehalogenase DpcA from Psychrobacter cryohalolentis K5. Acta Crystallogr F Struct Biol Commun 2019; 75:324-331. [PMID: 31045561 PMCID: PMC6497103 DOI: 10.1107/s2053230x19002796] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/24/2019] [Indexed: 12/29/2022] Open
Abstract
Haloalkane dehalogenases (HLDs) convert halogenated aliphatic pollutants to less toxic compounds by a hydrolytic mechanism. Owing to their broad substrate specificity and high enantioselectivity, haloalkane dehalogenases can function as biosensors to detect toxic compounds in the environment or can be used for the production of optically pure compounds. Here, the structural analysis of the haloalkane dehalogenase DpcA isolated from the psychrophilic bacterium Psychrobacter cryohalolentis K5 is presented at the atomic resolution of 1.05 Å. This enzyme exhibits a low temperature optimum, making it attractive for environmental applications such as biosensing at the subsurface environment, where the temperature typically does not exceed 25°C. The structure revealed that DpcA possesses the shortest access tunnel and one of the most widely open main tunnels among structural homologs of the HLD-I subfamily. Comparative analysis revealed major differences in the region of the α4 helix of the cap domain, which is one of the key determinants of the anatomy of the tunnels. The crystal structure of DpcA will contribute to better understanding of the structure-function relationships of cold-adapted enzymes.
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Affiliation(s)
- Katsiaryna Tratsiak
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Branisovska 1760, 370 05 Ceske Budejovice, Czech Republic
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nam. 2, 166 10 Prague, Czech Republic
| | - Tatyana Prudnikova
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Branisovska 1760, 370 05 Ceske Budejovice, Czech Republic
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of Czech Republic, v.v.i., Zamek 136, 373 33 Nove Hrady, Czech Republic
| | - Ivana Drienovska
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Jiri Damborsky
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
- International Clinical Research Center, St Anne’s University Hospital, Pekarska 53, 656 91 Brno, Czech Republic
| | - Jiri Brynda
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nam. 2, 166 10 Prague, Czech Republic
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, v.v.i., Videnska 1083, 142 20 Prague, Czech Republic
| | - Petr Pachl
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nam. 2, 166 10 Prague, Czech Republic
| | - Michal Kuty
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Branisovska 1760, 370 05 Ceske Budejovice, Czech Republic
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of Czech Republic, v.v.i., Zamek 136, 373 33 Nove Hrady, Czech Republic
| | - Radka Chaloupkova
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
- International Clinical Research Center, St Anne’s University Hospital, Pekarska 53, 656 91 Brno, Czech Republic
| | - Pavlina Rezacova
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nam. 2, 166 10 Prague, Czech Republic
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, v.v.i., Videnska 1083, 142 20 Prague, Czech Republic
| | - Ivana Kuta Smatanova
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Branisovska 1760, 370 05 Ceske Budejovice, Czech Republic
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of Czech Republic, v.v.i., Zamek 136, 373 33 Nove Hrady, Czech Republic
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Novototskaya-Vlasova K, Petrovskaya L, Kryukova E, Rivkina E, Dolgikh D, Kirpichnikov M. Expression and chaperone-assisted refolding of a new cold-active lipase from Psychrobacter cryohalolentis K5(T). Protein Expr Purif 2013; 91:96-103. [PMID: 23891837 DOI: 10.1016/j.pep.2013.07.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 07/03/2013] [Accepted: 07/08/2013] [Indexed: 11/19/2022]
Abstract
We describe cloning and expression of genes coding for lipase Lip2Pc and lipase-specific foldase LifPc from a psychrotrophic microorganism Psychrobacter cryohalolentis K5(T) isolated from a Siberian cryopeg (the lense of overcooled brine within permafrost). Upon expression in Escherichiacoli Lip2Pc accumulated in inclusion bodies while chaperone was synthesized in a soluble form. An efficient protocol for solubilization and subsequent refolding of the recombinant lipase in the presence of the truncated chaperone was developed. Using this procedure Lip2Pc with specific activity of 6900U/mg was obtained. Contrary to published data on other lipase-chaperone complexes, refolded Lip2Pc was mostly recovered from the complex with chaperone by metal-affinity chromatography. Recombinant Lip2Pc displayed maximum lipolytic activity at 25°C and pH 8.0 with p-nitrophenyl palmitate (C16) as a substrate. Activity assays conducted at different temperatures revealed that the recombinant Lip2Pc is a cold-adapted lipase with ability to utilize substrates with long (C10-C16) hydrocarbon chains in the temperature range from +5 to +65°C. It demonstrated relatively high stability at temperatures above 60°C and in the presence of various metal ions or organic solvents (ethanol, methanol, etc.). Non-ionic detergents, such as Triton X-100 and Tween 20 decreased Lip2Pc activity and SDS completely inhibited it.
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Affiliation(s)
- Ksenia Novototskaya-Vlasova
- Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Institutskaya str., 2, 142290 Pushchino, Moscow Region, Russian Federation.
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Tratsiak K, Degtjarik O, Drienovska I, Chrast L, Rezacova P, Kuty M, Chaloupkova R, Damborsky J, Kuta Smatanova I. Crystallographic analysis of new psychrophilic haloalkane dehalogenases: DpcA from Psychrobacter cryohalolentis K5 and DmxA from Marinobacter sp. ELB17. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:683-8. [PMID: 23722854 PMCID: PMC3668595 DOI: 10.1107/s1744309113012979] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 05/12/2013] [Indexed: 01/05/2023]
Abstract
Haloalkane dehalogenases are hydrolytic enzymes with a broad range of potential practical applications such as biodegradation, biosensing, biocatalysis and cellular imaging. Two newly isolated psychrophilic haloalkane dehalogenases exhibiting interesting catalytic properties, DpcA from Psychrobacter cryohalolentis K5 and DmxA from Marinobacter sp. ELB17, were purified and used for crystallization experiments. After the optimization of crystallization conditions, crystals of diffraction quality were obtained. Diffraction data sets were collected for native enzymes and complexes with selected ligands such as 1-bromohexane and 1,2-dichloroethane to resolutions ranging from 1.05 to 2.49 Å.
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Affiliation(s)
- Katsiaryna Tratsiak
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, CENAKVA and Institute of Complex Systems, Zamek 136, 373 33 Nove Hrady, Czech Republic
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic
| | - Oksana Degtjarik
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, CENAKVA and Institute of Complex Systems, Zamek 136, 373 33 Nove Hrady, Czech Republic
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic
- Institute of Nanobiology and Structural Biology GCRC, Academy of Sciences of the Czech Republic, Zamek 136, 373 33 Nove Hrady, Czech Republic
| | - Ivana Drienovska
- Loschmidt Laboratories, Department of Experimental Biology and Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Lukas Chrast
- Loschmidt Laboratories, Department of Experimental Biology and Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Pavlina Rezacova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic v.v.i., Videnska 1083, 142 20 Prague 4, Czech Republic
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i., Flemingovo nam. 2, 166 37 Prague, Czech Republic
| | - Michal Kuty
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, CENAKVA and Institute of Complex Systems, Zamek 136, 373 33 Nove Hrady, Czech Republic
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic
- Institute of Nanobiology and Structural Biology GCRC, Academy of Sciences of the Czech Republic, Zamek 136, 373 33 Nove Hrady, Czech Republic
| | - Radka Chaloupkova
- Loschmidt Laboratories, Department of Experimental Biology and Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Jiri Damborsky
- Loschmidt Laboratories, Department of Experimental Biology and Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Ivana Kuta Smatanova
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, CENAKVA and Institute of Complex Systems, Zamek 136, 373 33 Nove Hrady, Czech Republic
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic
- Institute of Nanobiology and Structural Biology GCRC, Academy of Sciences of the Czech Republic, Zamek 136, 373 33 Nove Hrady, Czech Republic
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Abstract
Understanding the behavior of proteins under freezing conditions is vital for detecting and locating extraterrestrial life in cold environments, such as those found on Mars and the icy moons of Jupiter and Saturn. This review highlights the importance of studying psychrophilic "cold-shock" proteins, a topic that has yet to be explored. A strategy for analyzing the psychrophilic RNA helicase protein CsdA (Psyc_1082) from Psychrobacter arcticus 273-4 as a key protein for life under freezing temperatures is proposed. The experimental model presented here was developed based on previous data from investigations of Escherichia coli, P. arcticus 273-4, and RNA helicases. P. arcticus 273-4 is considered a model for life in freezing environments. It is capable of growing in temperatures as cold as -10°C by using physiological strategies to survive not only in freezing temperatures but also under low-water-activity and limited-nutrient-availability conditions. The analyses of its genome, transcriptome, and proteome revealed specific adaptations that allow it to inhabit freezing environments by adopting a slow metabolic strategy rather than a cellular dormancy state. During growth at subzero temperatures, P. arcticus 273-4 genes related to energy metabolism and carbon substrate incorporation are downregulated, and genes for maintenance of membranes, cell walls, and nucleic acid motion are upregulated. At -6°C, P. arcticus 273-4 does not upregulate the expression of either RNA or protein chaperones; however, it upregulates the expression of its cold-shock induced DEAD-box RNA helicase protein A (CsdA - Psyc_1082). CsdA - Psyc_1082 was investigated as a key helper protein for sustaining life in subzero conditions. Proving CsdA - Psyc_1082 to be functional as a key protein for life under freezing temperatures may extend the known minimum growth temperature of a mesophilic cell and provide key information about the mechanisms that underlie cold-induced biological systems in icy worlds.
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Affiliation(s)
- Emanuele Kuhn
- Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, Nevada 89512, USA.
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Das D, Hervé M, Feuerhelm J, Farr CL, Chiu HJ, Elsliger MA, Knuth MW, Klock HE, Miller MD, Godzik A, Lesley SA, Deacon AM, Mengin-Lecreulx D, Wilson IA. Structure and function of the first full-length murein peptide ligase (Mpl) cell wall recycling protein. PLoS One 2011; 6:e17624. [PMID: 21445265 PMCID: PMC3060825 DOI: 10.1371/journal.pone.0017624] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 02/03/2011] [Indexed: 11/18/2022] Open
Abstract
Bacterial cell walls contain peptidoglycan, an essential polymer made by enzymes in the Mur pathway. These proteins are specific to bacteria, which make them targets for drug discovery. MurC, MurD, MurE and MurF catalyze the synthesis of the peptidoglycan precursor UDP-N-acetylmuramoyl-L-alanyl-γ-D-glutamyl-meso-diaminopimelyl-D-alanyl-D-alanine by the sequential addition of amino acids onto UDP-N-acetylmuramic acid (UDP-MurNAc). MurC-F enzymes have been extensively studied by biochemistry and X-ray crystallography. In gram-negative bacteria, ∼30-60% of the bacterial cell wall is recycled during each generation. Part of this recycling process involves the murein peptide ligase (Mpl), which attaches the breakdown product, the tripeptide L-alanyl-γ-D-glutamyl-meso-diaminopimelate, to UDP-MurNAc. We present the crystal structure at 1.65 Å resolution of a full-length Mpl from the permafrost bacterium Psychrobacter arcticus 273-4 (PaMpl). Although the Mpl structure has similarities to Mur enzymes, it has unique sequence and structure features that are likely related to its role in cell wall recycling, a function that differentiates it from the MurC-F enzymes. We have analyzed the sequence-structure relationships that are unique to Mpl proteins and compared them to MurC-F ligases. We have also characterized the biochemical properties of this enzyme (optimal temperature, pH and magnesium binding profiles and kinetic parameters). Although the structure does not contain any bound substrates, we have identified ∼30 residues that are likely to be important for recognition of the tripeptide and UDP-MurNAc substrates, as well as features that are unique to Psychrobacter Mpl proteins. These results provide the basis for future mutational studies for more extensive function characterization of the Mpl sequence-structure relationships.
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Affiliation(s)
- Debanu Das
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California, United States of America
| | - Mireille Hervé
- Université Paris-Sud, Laboratoire des Enveloppes Bactériennes et Antibiotiques, Orsay, France
- Centre National de la Recherche Scientifique, Institut de Biochimie et Biophysique Moléculaire et Cellulaire, Orsay, France
| | - Julie Feuerhelm
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Carol L. Farr
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Hsiu-Ju Chiu
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California, United States of America
| | - Marc-André Elsliger
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Mark W. Knuth
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Heath E. Klock
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Mitchell D. Miller
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California, United States of America
| | - Adam Godzik
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Center for Research in Biological Systems, University of California San Diego, La Jolla, California, United States of America
- Program on Bioinformatics and Systems Biology, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Scott A. Lesley
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Ashley M. Deacon
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California, United States of America
| | - Dominique Mengin-Lecreulx
- Université Paris-Sud, Laboratoire des Enveloppes Bactériennes et Antibiotiques, Orsay, France
- Centre National de la Recherche Scientifique, Institut de Biochimie et Biophysique Moléculaire et Cellulaire, Orsay, France
| | - Ian A. Wilson
- Joint Center for Structural Genomics (http://www.jcsg.org)
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
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Lazado CC, Caipang CMA, Gallage S, Brinchmann MF, Kiron V. Responses of Atlantic cod Gadus morhua head kidney leukocytes to phytase produced by gastrointestinal-derived bacteria. Fish Physiol Biochem 2010; 36:883-891. [PMID: 19844802 DOI: 10.1007/s10695-009-9364-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 10/08/2009] [Indexed: 05/28/2023]
Abstract
This study identified phytase-producing bacteria that were previously isolated from the gastrointestinal tract of Atlantic cod, Gadus morhua and determined its effect on head kidney leukocytes. Out of the 216 bacterial strains tested, the two phytase producers were identified as Pseudomonas sp. and Psychrobacter sp. based on their 16S rDNA sequence. Crude phytase from these two bacterial strains was produced employing the shake flask method. Even though the total protein of the crude phytase was not significantly different for the two bacteria, the phytase activity of the crude enzyme produced by Pseudomonas sp. (97.1±16.7 U) was significantly higher than that of the enzyme from Psychrobacter sp. (75.9±2.4 U). When cod head kidney leukocytes were incubated with the crude phytase (50 μg ml(-1)), it resulted in enhanced cell proliferation, higher myeloperoxidase, and acid phosphatase activities. Extracellular responses-respiratory burst activity and hydrogen peroxide production were not enhanced by the crude enzyme. As a consequence, the growth of two pathogenic bacteria Aeromonas salmonicida and Vibrio anguillarum was not suppressed by the supernatants obtained from head kidney leukocytes incubated with the crude bacterial phytase. Thus, the enzyme from phytase-producing intestinal bacteria of Atlantic cod can stimulate intracellular head kidney leukocyte activities but not the production of extracellular substances that are involved in antibacterial response. These have implications on the potential use of bacterial phytase as feed supplement to boost cellular immune response of the fish and could be employed as a health management strategy in culture systems.
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Affiliation(s)
- Carlo C Lazado
- Faculty of Biosciences and Aquaculture, Bodø University College, 8049, Bodø, Norway
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Zhang J, Lin S, Zeng R. Cloning, expression, and characterization of a cold-adapted lipase gene from an antarctic deep-sea psychrotrophic bacterium, Psychrobacter sp 7195. J Microbiol Biotechnol 2007; 17:604-10. [PMID: 18051271 DOI: pmid/18051271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A psychrotrophic strain 7195 showing extracellular lipolytic activity towards tributyrin was isolated from deep-sea sediment of Prydz Bay and identified as a Psychrobacter species. By screening a genomic DNA library of Psychrobacter sp. 7195, an open reading frame of 954 bp coding for a lipase gene, lipA1, was identified, cloned, and sequenced. The deduced LipA1 consisted of 317 amino acids with a molecular mass of 35,210 kDa. It had one consensus motif, G-N-S-M-G (GXSXG), containing the putative active-site serine, which was conserved in other cold-adapted lipolytic enzymes. The recombinant LipA1 was purified by column chromatography with DEAE Sepharose CL-4B, and Sephadex G-75, and preparative polyacrylamide gel electrophoresis, in sequence. The purified enzyme showed highest activity at 30 degrees C, and was unstable at temperatures higher than 30 degrees C, indicating that it was a typical cold-adapted enzyme. The optimal pH for activity was 9.0, and the enzyme was stable between pH 7.0-10.0 after 24 h incubation at 4 degrees C. The addition of Ca2+ and Mg2+ enhanced the enzyme activity of LipA1, whereas the Cd2, Zn2+, Co2+, Fe3+, Hg2+, Fe2+, Rb2+, and EDTA strongly inhibited the activity. The LipA1 was activated by various detergents, such as Triton X-100, Tween 80, Tween 40, Span 60, Span 40, CHAPS, and SDS, and showed better resistance towards them. Substrate specificity analysis showed that there was a preference for trimyristin and p-nitrophenyl myristate (C14 acyl groups).
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Affiliation(s)
- Jinwei Zhang
- Key Laboratory of Marine Biogenetic Resources, State Oceanic Administration, Xiamen, P R China
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Lee CK, Daniel RM, Shepherd C, Saul D, Cary SC, Danson MJ, Eisenthal R, Peterson ME. Eurythermalism and the temperature dependence of enzyme activity. FASEB J 2007; 21:1934-41. [PMID: 17341686 DOI: 10.1096/fj.06-7265com] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The "Equilibrium Model" has provided new tools for describing and investigating enzyme thermal adaptation. It has been shown that the effect of temperature on enzyme activity is not only governed by deltaG(double dagger)(cat) and deltaG(double dagger)(inact) but also by two new intrinsic parameters, deltaH(eq) and T(eq), which describe the enthalpy and midpoint, respectively, of a reversible equilibrium between active and inactive (but not denatured) forms of enzyme. Twenty-one enzymes from organisms with a wide range of growth temperatures were characterized using the Equilibrium Model. Statistical analysis indicates that T(eq) is a better predictor of growth temperature than enzyme stability (deltaG(double dagger)(inact)). As expected from the Equilibrium Model, deltaH(eq) correlates with catalytic temperature tolerance of enzymes and thus can be declared the first intrinsic and quantitative measure of enzyme eurythermalism. Other findings shed light on the evolution of psychrophilic and thermophilic enzymes. The findings suggest that the description of the Equilibrium Model of the effect of temperature on enzyme activity applies to all enzymes regardless of their temperature origins and that its associated parameters, deltaH(eq) and T(eq), are intrinsic and necessary parameters for characterizing the thermal properties of enzymes and their temperature adaptation and evolution.
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Affiliation(s)
- Charles K Lee
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
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9
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Kulakova L, Galkin A, Nakayama T, Nishino T, Esaki N. Cold-active esterase from Psychrobacter sp. Ant300: gene cloning, characterization, and the effects of Gly→Pro substitution near the active site on its catalytic activity and stability. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2004; 1696:59-65. [PMID: 14726205 DOI: 10.1016/j.bbapap.2003.09.008] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The gene encoding an esterase (PsyEst) of Psychrobacter sp. Ant300, a psychrophilic bacterium isolated from Antarctic soil, was cloned, sequenced, and expressed in Escherichia coli. PsyEst, which is a member of hormone-sensitive lipase (HSL) group of the lipase/esterase family, is a cold-active, themolabile enzyme with high catalytic activity at low temperatures (5-25 degrees C), low activation energy (e.g., 4.6 kcal/mol for hydrolysis of p-nitrophenyl butyrate), and a t(1/2) value of 16 min for thermal inactivation during incubation at 40 degrees C and pH 7.9. A three-dimensional structural model of PsyEst predicted that Gly(244) was located in the loop near the active site of PsyEst and that substitution of this amino-acid residue by proline should potentially rigidify the active-site environment of the enzyme. Thus, we introduced the Gly(244)-->Pro substitution into the enzyme. Stability studies showed that the t(1/2) value for thermal inactivation of the mutant during incubation at 40 degrees C and pH 7.9 was 11.6 h, which was significantly greater than that of the wild-type enzyme. The k(cat)/K(m) value of the mutant was lower for all substrates examined than the value of the wild type. Moreover, this amino-acid substitution caused a shift of the acyl-chain length specificity of the enzyme toward higher preference for short-chain fatty acid esters. All of these observations could be explained in terms of a decrease in active-site flexibility brought about by the mutation and were consistent with the hypothesis that cold activity and thermolability arise from local flexibility around the active site of the enzyme.
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Affiliation(s)
- Ljudmila Kulakova
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto-Fu, Kyoto 611-0011, Japan
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