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Vishnivetskaya TA, Buongiorno J, Bird J, Krivushin K, Spirina EV, Oshurkova V, Shcherbakova VA, Wilson G, Lloyd KG, Rivkina EM. Methanogens in the Antarctic Dry Valley permafrost. FEMS Microbiol Ecol 2018; 94:5033399. [DOI: 10.1093/femsec/fiy109] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 06/01/2018] [Indexed: 11/14/2022] Open
Affiliation(s)
- Tatiana A Vishnivetskaya
- Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, 142290, Russia
- University of Tennessee, Knoxville, TN, 37996, USA
| | | | - Jordan Bird
- University of Tennessee, Knoxville, TN, 37996, USA
| | - Kirill Krivushin
- Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, 142290, Russia
| | - Elena V Spirina
- Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, 142290, Russia
| | - Victoria Oshurkova
- Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, 142290, Russia
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, 142290, Russia
| | - Victoria A Shcherbakova
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, 142290, Russia
| | - Gary Wilson
- University of Otago, Dunedin, 9054, New Zealand
| | | | - Elizaveta M Rivkina
- Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, 142290, Russia
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2
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Characterization of a cold-adapted DNA photolyase from C. psychrerythraea 34H. Extremophiles 2017; 21:919-932. [PMID: 28726126 DOI: 10.1007/s00792-017-0953-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 07/09/2017] [Indexed: 10/19/2022]
Abstract
The phrB gene encoding a putative cold-adapted DNA photolyase was cloned from the bacterial genomic DNA of Colwellia psychrerythraea 34H, a psychrophilic bacterium. Recombinant DNA photolyase, rCpPL, was overexpressed and purified from three different vectors. rCpPL binds its DNA substrate by flipping a cyclobutane pyrimidine dimer (CPD) into its active site and repairs CPD-containing DNA in vitro. rCpPL contains one catalytic flavin adenine dinucleotide (FAD) cofactor, but displays promiscuity in cofactor binding, in which either a flavin mononucleotide (FMN) or a methenyltetrahydrofolate (MTHF) molecule is bound as an antenna molecule and found in sub-stoichiometric amounts. The UV/Vis spectrum of oxidized rCpPL shows that the FADOX absorption maximum is the most red-shifted reported for a PL, suggesting a unique cavity electrostatic environment. Modest FAD vibronic structure suggests that the binding pocket is more flexible than warmer PLs, corroborating the hypothesis that psychrophilic proteins must be highly flexible to function at low temperatures. Fluorescence excitation data show that the freshly purified flavin cofactor is in its fully reduced state (FADH¯). A homology analysis of PL protein structures spanning 70 °C in growth temperature supports the data that the structure of CpPL is quite different from its warmer cousins.
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3
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Walter A, Probst M, Hinterberger S, Müller H, Insam H. Biotic and abiotic dynamics of a high solid-state anaerobic digestion box-type container system. WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 49:26-35. [PMID: 26860425 DOI: 10.1016/j.wasman.2016.01.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 01/25/2016] [Accepted: 01/28/2016] [Indexed: 06/05/2023]
Abstract
A solid-state anaerobic digestion box-type container system for biomethane production was observed in 12 three-week batch fermentations. Reactor performance was monitored using physico-chemical analysis and the methanogenic community was identified using ANAEROCHIP-microarrays and quantitative PCR. A resilient community was found in all batches, despite variations in inoculum to substrate ratio, feedstock quality, and fluctuating reactor conditions. The consortia were dominated by mixotrophic Methanosarcina that were accompanied by hydrogenotrophic Methanobacterium, Methanoculleus, and Methanocorpusculum. The relationship between biotic and abiotic variables was investigated using bivariate correlation analysis and univariate analysis of variance. High amounts of biogas were produced in batches with high copy numbers of Methanosarcina. High copy numbers of Methanocorpusculum and extensive percolation, however, were found to negatively correlate with biogas production. Supporting these findings, a negative correlation was detected between Methanocorpusculum and Methanosarcina. Based on these results, this study suggests Methanosarcina as an indicator for well-functioning reactor performance.
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Affiliation(s)
- Andreas Walter
- Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria; Hochschule Hamm-Lippstadt, Biotechnologie, Marker Allee 76-78, 59063 Hamm, Germany.
| | - Maraike Probst
- Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria.
| | | | - Horst Müller
- Müller Abfallprojekte GmbH, Hauptstraße 34, 4675 Weibern, Austria.
| | - Heribert Insam
- Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria.
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4
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Taha, Siddiqui KS, Campanaro S, Najnin T, Deshpande N, Williams TJ, Aldrich‐Wright J, Wilkins M, Curmi PMG, Cavicchioli R. Single
TRAM
domain
RNA
‐binding proteins in
A
rchaea
: functional insight from
C
tr3 from the
A
ntarctic methanogen
M
ethanococcoides burtonii. Environ Microbiol 2016; 18:2810-24. [DOI: 10.1111/1462-2920.13229] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 01/13/2016] [Accepted: 01/13/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Taha
- School of Biotechnology and Biomolecular Sciences The University of New South Wales Sydney NSW 2052 Australia
| | - K. S. Siddiqui
- Life Sciences Department King Fahd University of Petroleum and Minerals Dhahran Kingdom of Saudi Arabia
| | - S. Campanaro
- Department of Biology University of Padua Via U. Bassi 58/B 35121 Padova Italy
| | - T. Najnin
- School of Biotechnology and Biomolecular Sciences The University of New South Wales Sydney NSW 2052 Australia
| | - N. Deshpande
- School of Biotechnology and Biomolecular Sciences The University of New South Wales Sydney NSW 2052 Australia
| | - T. J. Williams
- School of Biotechnology and Biomolecular Sciences The University of New South Wales Sydney NSW 2052 Australia
| | - J. Aldrich‐Wright
- Nanoscale Organization and Dynamic Group School of Science and Health Western Sydney University Penrith 2560 NSW Australia
| | - M. Wilkins
- School of Biotechnology and Biomolecular Sciences The University of New South Wales Sydney NSW 2052 Australia
| | - P. M. G. Curmi
- School of Physics The University of New South Wales Sydney NSW 2052 Australia
| | - R. Cavicchioli
- School of Biotechnology and Biomolecular Sciences The University of New South Wales Sydney NSW 2052 Australia
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5
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Schwartz MH, Pan T. Temperature dependent mistranslation in a hyperthermophile adapts proteins to lower temperatures. Nucleic Acids Res 2015; 44:294-303. [PMID: 26657639 PMCID: PMC4705672 DOI: 10.1093/nar/gkv1379] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/25/2015] [Indexed: 12/01/2022] Open
Abstract
All organisms universally encode, synthesize and utilize proteins that function optimally within a subset of growth conditions. While healthy cells are thought to maintain high translational fidelity within their natural habitats, natural environments can easily fluctuate outside the optimal functional range of genetically encoded proteins. The hyperthermophilic archaeon Aeropyrum pernix (A. pernix) can grow throughout temperature variations ranging from 70 to 100°C, although the specific factors facilitating such adaptability are unknown. Here, we show that A. pernix undergoes constitutive leucine to methionine mistranslation at low growth temperatures. Low-temperature mistranslation is facilitated by the misacylation of tRNALeu with methionine by the methionyl-tRNA synthetase (MetRS). At low growth temperatures, the A. pernix MetRS undergoes a temperature dependent shift in tRNA charging fidelity, allowing the enzyme to conditionally charge tRNALeu with methionine. We demonstrate enhanced low-temperature activity for A. pernix citrate synthase that is synthesized during leucine to methionine mistranslation at low-temperature growth compared to its high-fidelity counterpart synthesized at high-temperature. Our results show that conditional leucine to methionine mistranslation can make protein adjustments capable of improving the low-temperature activity of hyperthermophilic proteins, likely by facilitating the increasing flexibility required for greater protein function at lower physiological temperatures.
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Affiliation(s)
- Michael H Schwartz
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA Committee on Microbiology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA Committee on Microbiology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA
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6
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Point Mutation Ile137-Met Near Surface Conferred Psychrophilic Behaviour and Improved Catalytic Efficiency to Bacillus Lipase of 1.4 Subfamily. Appl Biochem Biotechnol 2015; 178:753-65. [DOI: 10.1007/s12010-015-1907-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 10/22/2015] [Indexed: 10/22/2022]
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7
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Identification and characterization of a cathepsin-L-like peptidase in Eimeria tenella. Parasitol Res 2014; 113:4335-48. [DOI: 10.1007/s00436-014-4107-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 08/26/2014] [Indexed: 11/26/2022]
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8
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Protein adaptations in archaeal extremophiles. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2013; 2013:373275. [PMID: 24151449 PMCID: PMC3787623 DOI: 10.1155/2013/373275] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 07/26/2013] [Accepted: 08/14/2013] [Indexed: 12/25/2022]
Abstract
Extremophiles, especially those in Archaea, have a myriad of adaptations that keep their cellular proteins stable and active under the extreme conditions in which they live. Rather than having one basic set of adaptations that works for all environments, Archaea have evolved separate protein features that are customized for each environment. We categorized the Archaea into three general groups to describe what is known about their protein adaptations: thermophilic, psychrophilic, and halophilic. Thermophilic proteins tend to have a prominent hydrophobic core and increased electrostatic interactions to maintain activity at high temperatures. Psychrophilic proteins have a reduced hydrophobic core and a less charged protein surface to maintain flexibility and activity under cold temperatures. Halophilic proteins are characterized by increased negative surface charge due to increased acidic amino acid content and peptide insertions, which compensates for the extreme ionic conditions. While acidophiles, alkaliphiles, and piezophiles are their own class of Archaea, their protein adaptations toward pH and pressure are less discernible. By understanding the protein adaptations used by archaeal extremophiles, we hope to be able to engineer and utilize proteins for industrial, environmental, and biotechnological applications where function in extreme conditions is required for activity.
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Dhaunta N, Arora K, Chandrayan SK, Guptasarma P. Introduction of a thermophile-sourced ion pair network in the fourth beta/alpha unit of a psychophile-derived triosephosphate isomerase from Methanococcoides burtonii significantly increases its kinetic thermal stability. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1023-33. [DOI: 10.1016/j.bbapap.2013.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 12/07/2012] [Accepted: 01/03/2013] [Indexed: 10/27/2022]
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10
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Saboia-Vahia L, Borges-Veloso A, Mesquita-Rodrigues C, Cuervo P, Dias-Lopes G, Britto C, Silva APDB, De Jesus JB. Trypsin-like serine peptidase profiles in the egg, larval, and pupal stages of Aedes albopictus. Parasit Vectors 2013; 6:50. [PMID: 23445661 PMCID: PMC3606343 DOI: 10.1186/1756-3305-6-50] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 02/18/2013] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Aedes albopictus, a ubiquitous mosquito, is one of the main vectors of dengue and yellow fever, representing an important threat to public health worldwide. Peptidases play key roles in processes such as digestion, oogenesis, and metamorphosis of insects. However, most of the information on the proteolytic enzymes of mosquitoes is derived from insects in the adult stages and is often directed towards the understanding of blood digestion. The aim of this study was to investigate the expression of active peptidases from the preimaginal stages of Ae. albopictus. METHODS Ae. albopictus eggs, larvae, and pupae were analyzed using zymography with susbtrate-SDS-PAGE. The pH, temperature and peptidase inhibitor sensitivity was evaluated. In addition, the proteolytic activities of larval instars were assayed using the fluorogenic substrate Z-Phe-Arg-AMC. RESULTS The proteolytic profile of the larval stage was composed of 8 bands ranging from 17 to 130 kDa. These enzymes displayed activity in a broad range of pH values, from 5.5 to 10.0. The enzymatic profile of the eggs was similar to that of the larvae, although the proteolytic bands of the eggs showed lower intensities. The pupal stage showed a complex proteolytic pattern, with at least 6 bands with apparent molecular masses ranging from 30 to 150 kDa and optimal activity at pH 7.5. Peptidases from larval instars were active from 10°C to 60°C, with optimal activity at temperatures between 37°C and 50°C. The proteolytic profile of both the larval and pupal stages was inhibited by phenyl-methyl sulfonyl-fluoride (PMSF) and Nα-Tosyl L-lysine chloromethyl ketone hydrochloride (TLCK), indicating that the main peptidases expressed during these developmental stages are trypsin-like serine peptidases. CONCLUSION The preimaginal stages of Ae. albopictus exhibited a complex profile of trypsin-like serine peptidase activities. A comparative analysis of the active peptidase profiles revealed differential expression of trypsin-like isoforms among the preimaginal stages, suggesting that some of these enzymes are stage specific. Additionally, a comparison of the peptidase expression between larvae from eggs collected in the natural environment and larvae obtained from the eggs of female mosquitoes maintained in colonies for a long period of time demonstrated that the proteolytic profile is invariable under such conditions.
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Affiliation(s)
- Leonardo Saboia-Vahia
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - André Borges-Veloso
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Camila Mesquita-Rodrigues
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Patricia Cuervo
- Laboratório de Pesquisa em Leishmaniose, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Geovane Dias-Lopes
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Constança Britto
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Ana Paula de Barros Silva
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Jose B De Jesus
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
- Departamento de Engenharia de Biossistemas, Universidade Federal de São João Del Rey, Minas Gerais, Brazil
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11
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Williams TJ, Wilkins D, Long E, Evans F, DeMaere MZ, Raftery MJ, Cavicchioli R. The role of planktonic Flavobacteria in processing algal organic matter in coastal East Antarctica revealed using metagenomics and metaproteomics. Environ Microbiol 2012; 15:1302-17. [PMID: 23126454 DOI: 10.1111/1462-2920.12017] [Citation(s) in RCA: 211] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/20/2012] [Accepted: 09/26/2012] [Indexed: 11/27/2022]
Abstract
Heterotrophic marine bacteria play key roles in remineralizing organic matter generated from primary production. However, far more is known about which groups are dominant than about the cellular processes they perform in order to become dominant. In the Southern Ocean, eukaryotic phytoplankton are the dominant primary producers. In this study we used metagenomics and metaproteomics to determine how the dominant bacterial and archaeal plankton processed bloom material. We examined the microbial community composition in 14 metagenomes and found that the relative abundance of Flavobacteria (dominated by Polaribacter) was positively correlated with chlorophyll a fluorescence, and the relative abundance of SAR11 was inversely correlated with both fluorescence and Flavobacteria abundance. By performing metaproteomics on the sample with the highest relative abundance of Flavobacteria (Newcomb Bay, East Antarctica) we defined how Flavobacteria attach to and degrade diverse complex organic material, how they make labile compounds available to Alphaproteobacteria (especially SAR11) and Gammaproteobacteria, and how these heterotrophic Proteobacteria target and utilize these nutrients. The presence of methylotrophic proteins for archaea and bacteria also indicated the importance of metabolic specialists. Overall, the study provides functional data for the microbial mechanisms of nutrient cycling at the surface of the coastal Southern Ocean.
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Affiliation(s)
- Timothy J Williams
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, 2052, Australia
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12
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A low-temperature-active alkaline pectate lyase from Xanthomonas campestris ACCC 10048 with high activity over a wide pH range. Appl Biochem Biotechnol 2012; 168:1489-500. [PMID: 22983714 DOI: 10.1007/s12010-012-9872-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 08/28/2012] [Indexed: 10/27/2022]
Abstract
Alkaline pectate lyases are favorable for the textile industry. Here, we report the gene cloning and expression of a low-temperature-active alkaline pectate lyase (PL D) from Xanthomonas campestris ACCC 10048. Deduced PL D consists of a putative 27-residue signal peptide and a catalytic domain of 320 residues belonging to family PF09492. Recombinant PL D (r-PL D) produced in Escherichia coli was purified to electrophoretic homogeneity with a single step of Ni(2+)-NTA affinity chromatography and showed an apparent molecular weight of ~38 kDa. The pH and temperature optima of r-PL D were found to be 9.0 °C and 30 °C, respectively. Compared with its microbial counterparts, r-PL D had higher activity over a wide pH range (>45 % of the maximum activity at pH 3.0-12.0) and at lower temperatures (>35 % of activity even at 0 °C). The K(m) and V(max) values of r-PL D for polygalacturonic acid were 4.9 gl(-1) and 30.1 μmolmin(-1) mg(-1), respectively. Compared with the commercial compound pectinase from Novozymes, r-PL D showed similar efficacy in reducing the intrinsic viscosity of polygalacturonic acid (35.1 % vs. 36.5 %) and in bioscouring of jute (10.25 % vs. 10.82 %). Thus, r-PL D is a valuable additive candidate for the textile industry.
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Dong X, Chen Z. Psychrotolerant methanogenic archaea: Diversity and cold adaptation mechanisms. SCIENCE CHINA-LIFE SCIENCES 2012; 55:415-21. [DOI: 10.1007/s11427-012-4320-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 04/10/2012] [Indexed: 11/24/2022]
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14
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De Vrieze J, Hennebel T, Boon N, Verstraete W. Methanosarcina: the rediscovered methanogen for heavy duty biomethanation. BIORESOURCE TECHNOLOGY 2012; 112:1-9. [PMID: 22418081 DOI: 10.1016/j.biortech.2012.02.079] [Citation(s) in RCA: 425] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 02/13/2012] [Accepted: 02/16/2012] [Indexed: 05/07/2023]
Abstract
Anaerobic digestion is an important technology in the framework of renewable energy production. The anaerobic digestion system is susceptible to perturbations due to the sensitivity of the methanogens towards environmental factors. Currently, technology is evolving from conventional waste treatment, i.e. the removal of pollutants, to very intensive biogas production from concentrated wastes, in the framework of bio-energy production. In the latter configuration Methanosarcina species appear to be of crucial importance. Methanosarcina sp. are, compared to other methanogens, quite robust towards different impairments. They are reported to be tolerant to total ammonium concentrations up to 7000 mg L(-1), salt concentrations up to 18,000 mg Na(+)L(-1), a pH shock of 0.8-1.0 units and acetate concentrations up to 15,000 mg CODL(-1). The possibilities of Methanosarcina sp. as key organisms in specific types of anaerobic digestion systems are demonstrated in this review.
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Affiliation(s)
- Jo De Vrieze
- Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium
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15
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Liu X, Meng K, Wang Y, Shi P, Yuan T, Yang P, Luo H, Bai Y, Yao B. Gene cloning, expression and characterization of an α-galactosidase from Pedobacter nyackensis MJ11 CGMCC 2503 with potential as an aquatic feed additive. World J Microbiol Biotechnol 2009. [DOI: 10.1007/s11274-009-0057-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Protein flexibility in psychrophilic and mesophilic trypsins. Evidence of evolutionary conservation of protein dynamics in trypsin-like serine-proteases. FEBS Lett 2008; 582:1008-18. [DOI: 10.1016/j.febslet.2008.02.048] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Revised: 01/29/2008] [Accepted: 02/19/2008] [Indexed: 11/17/2022]
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17
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Fedøy AE, Yang N, Martinez A, Leiros HKS, Steen IH. Structural and Functional Properties of Isocitrate Dehydrogenase from the Psychrophilic Bacterium Desulfotalea psychrophila Reveal a Cold-active Enzyme with an Unusual High Thermal Stability. J Mol Biol 2007; 372:130-49. [PMID: 17632124 DOI: 10.1016/j.jmb.2007.06.040] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 06/08/2007] [Accepted: 06/13/2007] [Indexed: 11/30/2022]
Abstract
Isocitrate dehydrogenase (IDH) has been studied extensively due to its central role in the Krebs cycle, catalyzing the oxidative NAD(P)(+)-dependent decarboxylation of isocitrate to alpha-ketoglutarate and CO(2). Here, we present the first crystal structure of IDH from a psychrophilic bacterium, Desulfotalea psychrophila (DpIDH). The structural information is combined with a detailed biochemical characterization and a comparative study with IDHs from the mesophilic bacterium Desulfitobacterium hafniense (DhIDH), porcine (PcIDH), human cytosolic (HcIDH) and the hyperthermophilic Thermotoga maritima (TmIDH). DpIDH was found to have a higher melting temperature (T(m)=66.9 degrees C) than its mesophilic homologues and a suboptimal catalytic efficiency at low temperatures. The thermodynamic activation parameters indicated a disordered active site, as seen also for the drastic increase in K(m) for isocitrate at elevated temperatures. A methionine cluster situated at the dimeric interface between the two active sites and a cluster of destabilizing charged amino acids in a region close to the active site might explain the poor isocitrate affinity. On the other hand, DpIDH was optimized for interacting with NADP(+) and the crystal structure revealed unique interactions with the cofactor. The highly acidic surface, destabilizing charged residues, fewer ion pairs and reduced size of ionic networks in DpIDH suggest a flexible global structure. However, strategic placement of ionic interactions stabilizing the N and C termini, and additional ionic interactions in the clasp domain as well as two enlarged aromatic clusters might counteract the destabilizing interactions and promote the increased thermal stability. The structure analysis of DpIDH illustrates how psychrophilic enzymes can adjust their flexibility in dynamic regions during their catalytic cycle without compromising the global stability of the protein.
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Affiliation(s)
- Anita-Elin Fedøy
- Department of Biology, University of Bergen, P.O. Box 7800, Jahnebakken 5, N-5020 Bergen, Norway
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18
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Abstract
By far the largest proportion of the Earth's biosphere is comprised of organisms that thrive in cold environments (psychrophiles). Their ability to proliferate in the cold is predicated on a capacity to synthesize cold-adapted enzymes. These enzymes have evolved a range of structural features that confer a high level of flexibility compared to thermostable homologs. High flexibility, particularly around the active site, is translated into low-activation enthalpy, low-substrate affinity, and high specific activity at low temperatures. High flexibility is also accompanied by a trade-off in stability, resulting in heat lability and, in the few cases studied, cold lability. This review addresses the structure, function, and stability of cold-adapted enzymes, highlighting the challenges for immediate and future consideration. Because of the unique properties of cold-adapted enzymes, they are not only an important focus in extremophile biology, but also represent a valuable model for fundamental research into protein folding and catalysis.
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Affiliation(s)
- Khawar Sohail Siddiqui
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia.
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19
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Abstract
Many archaea are extremophiles. They thrive at high temperatures, at high pressure and in concentrated acidic environments. Nevertheless, the largest proportion and greatest diversity of archaea exist in cold environments. Most of the Earth's biosphere is cold, and archaea represent a significant fraction of the biomass. Although psychrophilic archaea have long been the neglected majority, the study of these microorganisms is beginning to come of age. This review casts a spotlight on the ecology, adaptation biology and unique science that is being realized from studies on cold-adapted archaea.
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Affiliation(s)
- Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney NSW 2052, Australia.
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Goodchild A, Raftery M, Saunders NFW, Guilhaus M, Cavicchioli R. Cold Adaptation of the Antarctic Archaeon, Methanococcoides burtonii Assessed by Proteomics Using ICAT. J Proteome Res 2005; 4:473-80. [PMID: 15822924 DOI: 10.1021/pr049760p] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Using isotope coded affinity tag (ICAT) chromatography and liquid chromatography-mass spectrometry, 163 proteins were identified from the cold-adapted archaeon, Methanococcoides burtonii. 14 proteins were differentially expressed during growth at 4 degrees C and 23 degrees C. Knowledge of protein abundance, protein identity and gene arrangement was used to determine mechanisms of cold adaptation. Growth temperature was found to affect proteins involved in energy generation and biosynthesis linked to methanogenesis, membrane transport, transcription and protein folding, as well as affecting the expression of two hypothetical proteins. Pooling the data from this ICAT study with data from a previous two-dimensional gel electrophoresis study highlighted consistencies and differences between the two methods, and led us to conclude that the two approaches were generally complementary. This is the first report of ICAT applied to Archaea, or for the study of cold adaptation in any organism.
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Affiliation(s)
- Amber Goodchild
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, 2052, NSW, Australia
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21
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Nichols DS, Miller MR, Davies NW, Goodchild A, Raftery M, Cavicchioli R. Cold adaptation in the Antarctic Archaeon Methanococcoides burtonii involves membrane lipid unsaturation. J Bacteriol 2005; 186:8508-15. [PMID: 15576801 PMCID: PMC532414 DOI: 10.1128/jb.186.24.8508-8515.2004] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Direct analysis of membrane lipids by liquid chromatography-electrospray mass spectrometry was used to demonstrate the role of unsaturation in ether lipids in the adaptation of Methanococcoides burtonii to low temperature. A proteomics approach using two-dimensional liquid chromatography-mass spectrometry was used to identify enzymes involved in lipid biosynthesis, and a pathway for lipid biosynthesis was reconstructed from the M. burtonii draft genome sequence. The major phospholipids were archaeol phosphatidylglycerol, archaeol phosphatidylinositol, hydroxyarchaeol phosphatidylglycerol, and hydroxyarchaeol phosphatidylinositol. All phospholipid classes contained a series of unsaturated analogues, with the degree of unsaturation dependent on phospholipid class. The proportion of unsaturated lipids from cells grown at 4 degrees C was significantly higher than for cells grown at 23 degrees C. 3-Hydroxy-3-methylglutaryl coenzyme A synthase, farnesyl diphosphate synthase, and geranylgeranyl diphosphate synthase were identified in the expressed proteome, and most genes involved in the mevalonate pathway and processes leading to the formation of phosphatidylinositol and phosphatidylglycerol were identified in the genome sequence. In addition, M. burtonii encodes CDP-inositol and CDP-glycerol transferases and a number of homologs of the plant geranylgeranyl reductase. It therefore appears that the unsaturation of lipids may be due to incomplete reduction of an archaeol precursor rather than to a desaturase mechanism. This study shows that cold adaptation in M. burtonii involves specific changes in membrane lipid unsaturation. It also demonstrates that global methods of analysis for lipids and proteomics linked to a draft genome sequence can be effectively combined to infer specific mechanisms of key biological processes.
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Affiliation(s)
- David S Nichols
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
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22
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Kumar S, Nussinov R. Different roles of electrostatics in heat and in cold: adaptation by citrate synthase. Chembiochem 2004; 5:280-90. [PMID: 14997520 DOI: 10.1002/cbic.200300627] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Electrostatics plays a major role in heat adaptation by thermophilic proteins. Here we ask whether electrostatics similarly contributes to cold adaptation in psychrophilic proteins. We compare the sequences and structures of citrate synthases from the psychrophile Arthobacter Ds2-3R, from chicken, and from the hyperthermophile Pyrococcus furiosus. The three enzymes share similar packing, burial of nonpolar surface area, and main-chain hydrogen bonding. However, both psychrophilic and hyperthermophilic citrate synthases contain more charged residues, salt bridges, and salt-bridge networks than the mesophile. The electrostatic free-energy contributions toward protein stability by individual charged residues show greater variabilities in the psychrophilic citrate synthase than in the hyperthermophilic enzyme. The charged residues in the active-site regions of the psychrophile are more destabilizing than those in the active-site regions of the hyperthermophile. In the hyperthermophilic enzyme, salt bridges and their networks largely cluster in the active-site regions and at the dimer interface. In contrast, in the psychrophile, they are more dispersed throughout the structure. On average, salt bridges and their networks provide greater electrostatic stabilization to the thermophilic citrate synthase at 100 degrees C than to the psychrophilic enzyme at 0 degrees C. Electrostatics appears to play an important role in both heat and cold adaptation of citrate synthase. However, remarkably, the role may be different in the two types of enzyme: In the hyperthermophile, it may contribute to the integrity of both the protein dimer and the active site by possibly countering conformational disorder at high temperatures. On the other hand, in the psychrophile at low temperatures, electrostatics may contribute to enhance protein solvation and to ensure active-site flexibility.
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Affiliation(s)
- Sandeep Kumar
- Basic Research Program, SAIC-Frederick, Inc., Laboratory of Experimental and Computational Biology, NCI-Frederick, Building 469, Room 151, Frederick, MD 21702, USA
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23
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Carginale V, Trinchella F, Capasso C, Scudiero R, Parisi E. Gene amplification and cold adaptation of pepsin in Antarctic fish. A possible strategy for food digestion at low temperature. Gene 2004; 336:195-205. [PMID: 15246531 DOI: 10.1016/j.gene.2004.04.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Revised: 03/17/2004] [Accepted: 04/22/2004] [Indexed: 11/30/2022]
Abstract
Cold-adapted organisms have developed a number of adjustments at the molecular level to maintain metabolic functions at low temperatures. Among other features, they can produce enzymes characterized by a high turnover number or a high catalytic efficiency. The present work is aimed at investigating the process of food digestion at low temperature through the study of pepsins in Antarctic notothenioids. For such a purpose, we have cloned and sequenced three forms of pepsin A and a single form of gastricsin from the gastric mucosa of Trematomus bernacchii (rock cod). Phylogenetic analysis has suggested that the three pepsin A isotypes arose from two gene duplication events leading to the most ancestral pepsin A3 and to the most recent forms represented by pepsin A1 and pepsin A2. Molecular modeling has unraveled significant structural differences in these enzymes with respect to their mesophilic counterparts. Hydropathy and flexibility determined on the substrate-binding subsites of Antarctic and mesophilic pepsins have shown for pepsin A2 reduced hydropathy and increased flexibility at the level of the substrate cleft, features typical of cold-adapted enzymes. Northern blot analysis of RNA from rock cod gastric mucosa hybridized with molecular probes designed on specific regions of different pepsin forms has shown that rock cod pepsin genes are expressed at comparable levels. The present results suggest that the Antarctic rock cod adopted two different strategies to accomplish efficient protein digestion at low temperature. One mechanism is the gene duplication that increases enzyme production to compensate for the reduced kinetic efficiency, the other is the expression of a new enzyme provided with features typical of cold-adapted enzymes.
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MESH Headings
- Acclimatization/genetics
- Amino Acid Sequence
- Animal Nutritional Physiological Phenomena
- Animals
- Antarctic Regions
- Base Sequence
- Blotting, Northern
- Cloning, Molecular
- Cold Temperature
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Fish Proteins/chemistry
- Fish Proteins/genetics
- Fish Proteins/metabolism
- Gene Amplification
- Gene Expression Regulation, Enzymologic
- Isoenzymes/chemistry
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Models, Molecular
- Molecular Sequence Data
- Pepsin A/chemistry
- Pepsin A/genetics
- Pepsin A/metabolism
- Perciformes/genetics
- Perciformes/metabolism
- Phylogeny
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Structural Homology, Protein
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Affiliation(s)
- Vincenzo Carginale
- CNR Institute of Protein Biochemistry, via Marconi 10, 80125 Napoli, Italy
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24
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Sagar MB, Lucast L, Doudna JA. Conserved but nonessential interaction of SRP RNA with translation factor EF-G. RNA (NEW YORK, N.Y.) 2004; 10:772-8. [PMID: 15100432 PMCID: PMC1370567 DOI: 10.1261/rna.5266504] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
4.5S RNA is essential for viability of Escherichia coli, and forms a key component of the signal recognition particle (SRP), a ubiquitous ribonucleoprotein complex responsible for cotranslational targeting of secretory proteins. 4.5S RNA also binds independently to elongation factor G (EF-G), a five-domain GTPase that catalyzes the translocation step during protein biosynthesis on the ribosome. Point mutations in EF-G suppress deleterious effects of 4.5S RNA depletion, as do mutations in the EF-G binding site within ribosomal RNA, suggesting that 4.5S RNA might play a critical role in ribosome function in addition to its role in SRP. Here we show that 4.5S RNA and EF-G form a phylogenetically conserved, low-affinity but highly specific complex involving sequence elements required for 4.5S binding to its cognate SRP protein, Ffh. Mutational analysis indicates that the same molecular structure of 4.5S RNA is recognized in each case. Surprisingly, however, the suppressor mutant forms of EF-G bind very weakly or undetectably to 4.5S RNA, implying that cells can survive 4.5S RNA depletion by decreasing the affinity between 4.5S RNA and the translational machinery. These data suggest that SRP function is the essential role of 4.5S RNA in bacteria.
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Affiliation(s)
- Madi Bidya Sagar
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
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25
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Abstract
More than three-quarters of the Earth's surface is occupied by cold ecosystems, including the ocean depths, and polar and alpine regions. These permanently cold environments have been successfully colonized by a class of extremophilic microorganisms that are known as psychrophiles (which literally means cold-loving). The ability to thrive at temperatures that are close to, or below, the freezing point of water requires a vast array of adaptations to maintain the metabolic rates and sustained growth compatible with life in these severe environmental conditions.
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Affiliation(s)
- Georges Feller
- Laboratory of Biochemistry, Institute of Chemistry B6, University of Liège, B-4000 Liège-Sart Tilman, Belgium.
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26
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Saunders NFW, Thomas T, Curmi PMG, Mattick JS, Kuczek E, Slade R, Davis J, Franzmann PD, Boone D, Rusterholtz K, Feldman R, Gates C, Bench S, Sowers K, Kadner K, Aerts A, Dehal P, Detter C, Glavina T, Lucas S, Richardson P, Larimer F, Hauser L, Land M, Cavicchioli R. Mechanisms of thermal adaptation revealed from the genomes of the Antarctic Archaea Methanogenium frigidum and Methanococcoides burtonii. Genome Res 2003; 13:1580-8. [PMID: 12805271 PMCID: PMC403754 DOI: 10.1101/gr.1180903] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We generated draft genome sequences for two cold-adapted Archaea, Methanogenium frigidum and Methanococcoides burtonii, to identify genotypic characteristics that distinguish them from Archaea with a higher optimal growth temperature (OGT). Comparative genomics revealed trends in amino acid and tRNA composition, and structural features of proteins. Proteins from the cold-adapted Archaea are characterized by a higher content of noncharged polar amino acids, particularly Gln and Thr and a lower content of hydrophobic amino acids, particularly Leu. Sequence data from nine methanogen genomes (OGT 15 degrees -98 degrees C) were used to generate 1111 modeled protein structures. Analysis of the models from the cold-adapted Archaea showed a strong tendency in the solvent-accessible area for more Gln, Thr, and hydrophobic residues and fewer charged residues. A cold shock domain (CSD) protein (CspA homolog) was identified in M. frigidum, two hypothetical proteins with CSD-folds in M. burtonii, and a unique winged helix DNA-binding domain protein in M. burtonii. This suggests that these types of nucleic acid binding proteins have a critical role in cold-adapted Archaea. Structural analysis of tRNA sequences from the Archaea indicated that GC content is the major factor influencing tRNA stability in hyperthermophiles, but not in the psychrophiles, mesophiles or moderate thermophiles. Below an OGT of 60 degrees C, the GC content in tRNA was largely unchanged, indicating that any requirement for flexibility of tRNA in psychrophiles is mediated by other means. This is the first time that comparisons have been performed with genome data from Archaea spanning the growth temperature extremes from psychrophiles to hyperthermophiles.
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Affiliation(s)
- Neil F W Saunders
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
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27
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Alimenti C, Ortenzi C, Carratore V, Luporini P. Structural characterization of En-1, a cold-adapted protein pheromone isolated from the Antarctic ciliate Euplotes nobilii. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1621:17-21. [PMID: 12667606 DOI: 10.1016/s0304-4165(03)00011-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The second of two diffusible cell signal proteins (pheromones) purified from a wild-type strain of the Antarctic ciliate, Euplotes nobilii, has been determined by automated Edman degradation of the whole molecule and peptides generated by its chymotryptic digestion. The proposed sequence of 52 amino acids of this new pheromone, designated En-1, is: NPEDWFTPDT(10)CAYGDSNTAW(20)TTCTTPGQTC(30)YTCCSSCFDV(40)VGEQACQMSA(50)QC. In common with the previously determined 60-amino-acid sequence of the other pheromone, En-2, it bears eight cysteines in conserved positions (presumably linked into four conserved intrachain disulfide bonds), and physicochemical features of potential significance for cold adaptation, such as a reduced hydrophobicity, an increased solvent accessibility, and an improved local backbone flexibility. However, En-1 diverges from En-2 for having evolved a threonine cluster in the place of a glycine cluster to apparently make more flexible a region that is likely functionally important.
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Affiliation(s)
- Claudio Alimenti
- Dipartimento di Biologia Molecolare Cellulare e Animale, University of Camerino, Via Camerini 5, 62032 Camerino (MC), Italy
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28
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Thomas T, Kumar N, Cavicchioli R. Effects of ribosomes and intracellular solutes on activities and stabilities of elongation factor 2 proteins from psychrotolerant and thermophilic methanogens. J Bacteriol 2001; 183:1974-82. [PMID: 11222595 PMCID: PMC95092 DOI: 10.1128/jb.183.6.1974-1982.2001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Low-temperature-adapted archaea are abundant in the environment, yet little is known about the thermal adaptation of their proteins. We have previously compared elongation factor 2 (EF-2) proteins from Antarctic (Methanococcoides burtonii) and thermophilic (Methanosarcina thermophila) methanogens and found that the M. burtonii EF-2 had greater intrinsic activity at low temperatures and lower thermal stability at high temperatures (T. Thomas and R. Cavicchioli, J. Bacteriol. 182:1328-1332, 2000). While the gross thermal properties correlated with growth temperature, the activity and stability profiles of the EF-2 proteins did not precisely match the optimal growth temperature of each organism. This indicated that intracellular components may affect the thermal characteristics of the EF-2 proteins, and in this study we examined the effects of ribosomes and intracellular solutes. At a high growth temperature the thermophile produced high levels of potassium glutamate, which, when assayed in vitro with EF-2, retarded thermal unfolding and increased catalytic efficiency. In contrast, for the Antarctic methanogen adaptation to growth at a low temperature did not involve the accumulation of stabilizing organic solutes but appeared to result from an increased affinity of EF-2 for GTP and high levels of EF-2 in the cell relative to its low growth rate. Furthermore, ribosomes greatly stimulated GTPase activity and moderately stabilized both EF-2 proteins. These findings illustrate the different physiological strategies that have evolved in two phylogenetically related but thermally distinct methanogens to enable EF-2 to function satisfactorily.
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Affiliation(s)
- T Thomas
- School of Microbiology and Immunology, The University of New South Wales, Sydney, NSW, 2052, Australia
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29
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30
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Sheridan PP, Panasik N, Coombs JM, Brenchley JE. Approaches for deciphering the structural basis of low temperature enzyme activity. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1543:417-433. [PMID: 11150617 DOI: 10.1016/s0167-4838(00)00237-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An increasing number of enzymes active at low temperature are being studied to help determine the structural features important for cold-activity. This review examines the diversity of prokaryotic cold-active enzymes and the features proposed to account for low temperature activity. We then consider the difficulty of identifying the key structural features needed for cold-activity and the need to compare enzymes having different temperature optima from phylogenetically related organisms to determine features responsible for low temperature activity. In addition to studying naturally occurring enzymes, directed evolution experiments are discussed as methods for examining the proposed mechanisms influencing the thermal dependence of activity.
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Affiliation(s)
- P P Sheridan
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 16802, University Park, PA, USA.
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31
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Lim J, Thomas T, Cavicchioli R. Low temperature regulated DEAD-box RNA helicase from the Antarctic archaeon, Methanococcoides burtonii. J Mol Biol 2000; 297:553-67. [PMID: 10731411 DOI: 10.1006/jmbi.2000.3585] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
DEAD-box RNA helicases, by unwinding duplex RNA in bacteria and eukaryotes, are involved in essential cellular processes, including translation initiation and ribosome biogenesis, and have recently been implicated in enabling bacteria to survive cold-shock and grow at low temperature. Despite these critical physiological roles, they have not been characterized in archaea. Due to their presumed importance in removing cold-stabilised secondary structures in mRNA, we have characterised a putative DEAD-box RNA helicase gene (deaD) from the Antarctic methanogen, Methanococcoides burtonii. The encoded protein, DeaD is predicted to contain a core element involved in ATP hydrolysis and RNA-binding, and an unusual C-terminal domain that contains seven perfect, trideca-peptide, direct repeats that may be involved in RNA binding. Alignment and phylogenetic analyses were performed on the core regions of the M. burtonii and other DEAD-box RNA helicases. These revealed a loose but consistent clustering of archaeal and bacterial sequences and enabled the generation of a prokaryotic-specific consensus sequence. The consensus highlights the importance of residues other than the eight motifs that are often associated with DEAD-box RNA helicases, as well as de-emphasising the importance of the "A" residue within the "DEAD" motif. Cells growing at 4 degrees C contained abundant levels of deaD mRNA, however no mRNA was detected in cells growing at 23 degrees C (the optimal temperature for growth). The transcription initiation site was mapped downstream from an archaeal box-A element (TATA box), which preceded a long (113 nucleotides) 5'-untranslated region (5'-UTR). Within the 5'-UTR was an 11 bp sequence that closely matches (nine out of 11) cold-box elements that are present in the 5'-UTRs of cold-shock induced genes from bacteria. To determine if the archaeal 5'-UTR performs an analagous function to the bacterial 5'-UTRs, the archaeal deaD 5'-UTR was transcribed in E. coli under the control of the cspA promoter and transcriptional terminator. It has previously been reported that overexpression of the cspA 5'-UTR leads to an extended cold-shock response due to the 5'-UTR titrating cellular levels of a cold-shock repressor protein(s). In our hands, the cold-shock protein profiles resulting from overexpression of Escherichia coli cspA and M. burtonii deaD 5'-UTRs were similar, however they did not differ from those for the overexpression of a control plasmid lacking a 5'-UTR. In association with other recent data from E. coli, our results indicate that the role of the 5'-UTR in gene regulation is presently unclear. Irrespective of the mechanisms, it is striking that highly similar 5'-UTRs with cold-box elements are present in cold induced genes from E. coli, Anabaena and M. burtonii. This is the first study examining low temperature regulation in archaea and provides initial evidence that gene expression from a cold adapted archaeon involves a bacterial-like transcriptional regulatory mechanism. In addition, it provides the foundation for further studies into the function and regulation of DEAD-box RNA helicases in archaea, and in particular, their roles in low temperature adaptation.
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Affiliation(s)
- J Lim
- School of Microbiology and Immunology, The University of New South Wales, Sydney, UNSW, 2052, Australia
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32
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Thomas T, Cavicchioli R. Effect of temperature on stability and activity of elongation factor 2 proteins from Antarctic and thermophilic methanogens. J Bacteriol 2000; 182:1328-32. [PMID: 10671454 PMCID: PMC94419 DOI: 10.1128/jb.182.5.1328-1332.2000] [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] [Received: 09/21/1999] [Accepted: 12/09/1999] [Indexed: 11/20/2022] Open
Abstract
Despite the presence and abundance of archaea in low-temperature environments, little information is available regarding their physiological and biochemical properties. In order to investigate the adaptation of archaeal proteins to low temperatures, we purified and characterized the elongation factor 2 (EF-2) protein from the Antarctic methanogen Methanococcoides burtonii, which was expressed in Escherichia coli, and compared it to the recombinant EF-2 protein from a phylogenetically related thermophile, Methanosarcina thermophila. Using differential scanning calorimetry to assess protein stability and enzyme assays for the intrinsic GTPase activity, we identified biochemical and biophysical properties that are characteristic of the cold-adapted protein. This includes a higher activity at low temperatures caused by a decrease of the activation energy necessary for GTP hydrolysis and a decreased activation energy for the irreversible denaturation of the protein, which indicates a less thermostable structure. Comparison of the in vitro properties of the proteins with the temperature-dependent characteristics of growth of the organisms indicates that additional cytoplasmic factors are likely to be important for the complete thermal adaptation of the proteins in vivo. This is the first study to address thermal adaptation of proteins from a free-living, cold-adapted archaeon, and our results indicate that the ability of the Antarctic methanogen to adapt to the cold is likely to involve protein structural changes.
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Affiliation(s)
- T Thomas
- School of Microbiology and Immunology, The University of New South Wales, Sydney 2052, NSW, Australia
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33
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Macario AJ, Lange M, Ahring BK, Conway de Macario E. Stress genes and proteins in the archaea. Microbiol Mol Biol Rev 1999; 63:923-67, table of contents. [PMID: 10585970 PMCID: PMC98981 DOI: 10.1128/mmbr.63.4.923-967.1999] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The field covered in this review is new; the first sequence of a gene encoding the molecular chaperone Hsp70 and the first description of a chaperonin in the archaea were reported in 1991. These findings boosted research in other areas beyond the archaea that were directly relevant to bacteria and eukaryotes, for example, stress gene regulation, the structure-function relationship of the chaperonin complex, protein-based molecular phylogeny of organisms and eukaryotic-cell organelles, molecular biology and biochemistry of life in extreme environments, and stress tolerance at the cellular and molecular levels. In the last 8 years, archaeal stress genes and proteins belonging to the families Hsp70, Hsp60 (chaperonins), Hsp40(DnaJ), and small heat-shock proteins (sHsp) have been studied. The hsp70(dnaK), hsp40(dnaJ), and grpE genes (the chaperone machine) have been sequenced in seven, four, and two species, respectively, but their expression has been examined in detail only in the mesophilic methanogen Methanosarcina mazei S-6. The proteins possess markers typical of bacterial homologs but none of the signatures distinctive of eukaryotes. In contrast, gene expression and transcription initiation signals and factors are of the eucaryal type, which suggests a hybrid archaeal-bacterial complexion for the Hsp70 system. Another remarkable feature is that several archaeal species in different phylogenetic branches do not have the gene hsp70(dnaK), an evolutionary puzzle that raises the important question of what replaces the product of this gene, Hsp70(DnaK), in protein biogenesis and refolding and for stress resistance. Although archaea are prokaryotes like bacteria, their Hsp60 (chaperonin) family is of type (group) II, similar to that of the eukaryotic cytosol; however, unlike the latter, which has several different members, the archaeal chaperonin system usually includes only two (in some species one and in others possibly three) related subunits of approximately 60 kDa. These form, in various combinations depending on the species, a large structure or chaperonin complex sometimes called the thermosome. This multimolecular assembly is similar to the bacterial chaperonin complex GroEL/S, but it is made of only the large, double-ring oligomers each with eight (or nine) subunits instead of seven as in the bacterial complex. Like Hsp70(DnaK), the archaeal chaperonin subunits are remarkable for their evolution, but for a different reason. Ubiquitous among archaea, the chaperonins show a pattern of recurrent gene duplication-hetero-oligomeric chaperonin complexes appear to have evolved several times independently. The stress response and stress tolerance in the archaea involve chaperones, chaperonins, other heat shock (stress) proteins including sHsp, thermoprotectants, the proteasome, as yet incompletely understood thermoresistant features of many molecules, and formation of multicellular structures. The latter structures include single- and mixed-species (bacterial-archaeal) types. Many questions remain unanswered, and the field offers extraordinary opportunities owing to the diversity, genetic makeup, and phylogenetic position of archaea and the variety of ecosystems they inhabit. Specific aspects that deserve investigation are elucidation of the mechanism of action of the chaperonin complex at different temperatures, identification of the partners and substitutes for the Hsp70 chaperone machine, analysis of protein folding and refolding in hyperthermophiles, and determination of the molecular mechanisms involved in stress gene regulation in archaeal species that thrive under widely different conditions (temperature, pH, osmolarity, and barometric pressure). These studies are now possible with uni- and multicellular archaeal models and are relevant to various areas of basic and applied research, including exploration and conquest of ecosystems inhospitable to humans and many mammals and plants.
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Affiliation(s)
- A J Macario
- Wadsworth Center, New York State Department of Health, and Department of Biomedical Sciences, School of Public Health, The University at Albany, Albany, New York 12201-0509, USA
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Developments with antarctic microorganisms: culture collections, bioactivity screening, taxonomy, PUFA production and cold-adapted enzymes. Curr Opin Biotechnol 1999; 10:240-6. [PMID: 10361072 DOI: 10.1016/s0958-1669(99)80042-1] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
There have been recent research developments with Antarctic prokaryotes in the areas of isolations of novel bacterial, culture collections, bioactivity screening, taxonomy, production of polyunsaturated fatty acids (PUFAs), cold-adapted enzymes and bioremediation. Research to date confirms the novelty of bacteria isolated from this extreme environment. Opportunities now exist to exploit these and other findings to develop possible new biotechnological products from Antarctic microorganisms.
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