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Kumari M, Padhi S, Sharma S, Phukon LC, Singh SP, Rai AK. Biotechnological potential of psychrophilic microorganisms as the source of cold-active enzymes in food processing applications. 3 Biotech 2021; 11:479. [PMID: 34790503 DOI: 10.1007/s13205-021-03008-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/29/2021] [Indexed: 12/13/2022] Open
Abstract
Microorganisms striving in extreme environments and exhibiting optimal growth and reproduction at low temperatures, otherwise known as psychrophilic microorganisms, are potential sources of cold-active enzymes. Owing to higher stability and cold activity, these enzymes are gaining enormous attention in numerous industrial bioprocesses. Applications of several cold-active enzymes have been established in the food industry, e.g., β-galactosidase, pectinase, proteases, amylases, xylanases, pullulanases, lipases, and β-mannanases. The enzyme engineering approaches and the accumulating knowledge of protein structure and function have made it possible to improve the catalytic properties of interest and express the candidate enzyme in a heterologous host for a higher level of enzyme production. This review compiles the relevant and recent information on the potential uses of different cold-active enzymes in the food industry.
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Affiliation(s)
- Megha Kumari
- Institute of Bioresources and Sustainable Development, Regional Centre, Sikkim, India
| | - Srichandan Padhi
- Institute of Bioresources and Sustainable Development, Regional Centre, Sikkim, India
| | - Swati Sharma
- Institute of Bioresources and Sustainable Development, Regional Centre, Sikkim, India
| | - Loreni Chiring Phukon
- Institute of Bioresources and Sustainable Development, Regional Centre, Sikkim, India
| | - Sudhir P Singh
- Centre of Innovative and Applied Bioprocessing, Mohali, India
| | - Amit Kumar Rai
- Institute of Bioresources and Sustainable Development, Regional Centre, Sikkim, India
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Purified lactases versus whole-cell lactases-the winner takes it all. Appl Microbiol Biotechnol 2021; 105:4943-4955. [PMID: 34115184 DOI: 10.1007/s00253-021-11388-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/25/2021] [Accepted: 06/02/2021] [Indexed: 10/21/2022]
Abstract
Lactose-free dairy products are in great demand worldwide due to the high prevalence of lactose intolerance. To make lactose-free dairy products, commercially available β-galactosidase enzymes, also termed lactases, are used to break down lactose to its constituent monosaccharides, glucose and galactose. In this mini-review, the characteristics of lactase enzymes, their origin, and ways of use are discussed in light of their potential for hydrolyzing lactose. We also discuss whole-cell lactase catalysts, which appear to have great potential in terms of cost reduction and convenience, and which are more natural alternatives to purified enzymes. Lactic acid bacteria (LAB) already used in food fermentations seem to be optimal candidates for whole-cell lactases. However, they have not been industrially exploited yet due to technical hurdles. For whole-cell lactases to be efficient, the lactase enzymes inside the cells must be made available for lactose hydrolysis, and thus, cells need to be permeabilized or disrupted prior to use. Here we review state-of-the-art approaches for disrupting or permeabilizing microorganisms. Lastly, based on recent scientific achievements, we propose a novel, resource-efficient, and low-cost scenario for achieving lactose hydrolysis at a dairy plant using a LAB whole-cell lactase.Key points• Lactases (β-galactosidase) are essential for producing lactose-free dairy products• Novel permeabilization techniques facilitate the use of LAB lactases• Whole-cell lactase catalysts have great potential for reducing costs and resources Graphical abstract.
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Encapsulated NOLA™ Fit 5500 Lactase—An Economically Beneficial Way to Obtain Lactose-Free Milk at Low Temperature. Catalysts 2021. [DOI: 10.3390/catal11050527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The current requirements of industrial biocatalysis are related to economically beneficial and environmentally friendly processes. Such a strategy engages low-temperature reactions. The presented approach is essential, especially in food processes, where temperature affects the quality and nutritional value foodstuffs. The subject of the study is the hydrolysis of lactose with the commercial lactase NOLA™ Fit 5500 (NOLA). The complete decomposition of lactose into two monosaccharides gives a sweeter product, recommended for lactose intolerant people and those controlling a product’s caloric content. The hydrolysis reaction was performed at 15 °C, which is related to milk transportation and storage temperature. The enzyme showed activity over the entire range of substrate concentrations (up to 55 g/L lactose). For reusability and easy isolation, the enzyme was encapsulated in a sodium alginate network. Its stability allows carrying out six cycles of the complete hydrolysis of lactose to monosaccharides, lasting from two to four hours. During the study, the kinetic description of native and encapsulated NOLA was conducted. As a result, the model of competitive galactose inhibition and glucose mixed influence (competitive inhibition and activation) was proposed. The capsule size does not influence the reaction rate; thus, the substrate diffusion into capsules can be omitted from the process description. The prepared 4 mm capsules are easy to separate between cycles, e.g., using sieves.
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Antarctic Rahnella inusitata: A Producer of Cold-Stable β-Galactosidase Enzymes. Int J Mol Sci 2021; 22:ijms22084144. [PMID: 33923711 PMCID: PMC8074230 DOI: 10.3390/ijms22084144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/28/2021] [Accepted: 04/02/2021] [Indexed: 11/18/2022] Open
Abstract
There has been a recent increase in the exploration of cold-active β-galactosidases, as it offers new alternatives for the dairy industry, mainly in response to the current needs of lactose-intolerant consumers. Since extremophilic microbial compounds might have unique physical and chemical properties, this research aimed to study the capacity of Antarctic bacterial strains to produce cold-active β-galactosidases. A screening revealed 81 out of 304 strains with β-galactosidase activity. The strain Se8.10.12 showed the highest enzymatic activity. Morphological, biochemical, and molecular characterization based on whole-genome sequencing confirmed it as the first Rahnella inusitata isolate from the Antarctic, which retained 41–62% of its β-galactosidase activity in the cold (4 °C–15 °C). Three β-galactosidases genes were found in the R. inusitata genome, which belong to the glycoside hydrolase families GH2 (LacZ and EbgA) and GH42 (BglY). Based on molecular docking, some of these enzymes exhibited higher lactose predicted affinity than the commercial control enzyme from Aspergillus oryzae. Hence, this work reports a new Rahnella inusitata strain from the Antarctic continent as a prominent cold-active β-galactosidase producer.
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Wang L, Mou Y, Guan B, Hu Y, Zhang Y, Zeng J, Ni Y. Genome sequence of the psychrophilic Cryobacterium sp. LW097 and characterization of its four novel cold-adapted β-galactosidases. Int J Biol Macromol 2020; 163:2068-2083. [DOI: 10.1016/j.ijbiomac.2020.09.100] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/21/2020] [Accepted: 09/14/2020] [Indexed: 12/24/2022]
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Kohli I, Joshi NC, Mohapatra S, Varma A. Extremophile - An Adaptive Strategy for Extreme Conditions and Applications. Curr Genomics 2020; 21:96-110. [PMID: 32655304 PMCID: PMC7324872 DOI: 10.2174/1389202921666200401105908] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/27/2020] [Accepted: 03/19/2020] [Indexed: 11/22/2022] Open
Abstract
The concurrence of microorganisms in niches that are hostile like extremes of temperature, pH, salt concentration and high pressure depends upon novel molecular mechanisms to enhance the stability of their proteins, nucleic acids, lipids and cell membranes. The structural, physiological and genomic features of extremophiles that make them capable of withstanding extremely selective environmental conditions are particularly fascinating. Highly stable enzymes exhibiting several industrial and biotechnological properties are being isolated and purified from these extremophiles. Successful gene cloning of the purified extremozymes in the mesophilic hosts has already been done. Various extremozymes such as amylase, lipase, xylanase, cellulase and protease from thermophiles, halothermophiles and psychrophiles are of industrial interests due to their enhanced stability at forbidding conditions. In this review, we made an attempt to point out the unique features of extremophiles, particularly thermophiles and psychrophiles, at the structural, genomic and proteomic levels, which allow for functionality at harsh conditions focusing on the temperature tolerance by them.
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Affiliation(s)
- Isha Kohli
- Amity Institute of Microbial Technology, Amity University, Noida, India
| | - Naveen C. Joshi
- Amity Institute of Microbial Technology, Amity University, Noida, India
| | - Swati Mohapatra
- Amity Institute of Microbial Technology, Amity University, Noida, India
| | - Ajit Varma
- Amity Institute of Microbial Technology, Amity University, Noida, India
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Abstract
Despite the typical human notion that the Earth is a habitable planet, over three quarters of our planet is uninhabitable by us without assistance. The organisms that live and thrive in these “inhospitable” environments are known by the name extremophiles and are found in all Domains of Life. Despite our general lack of knowledge about them, they have already assisted humans in many ways and still have much more to give. In this review, I describe how they have adapted to live/thrive/survive in their niches, helped scientists unlock major scientific discoveries, advance the field of biotechnology, and inform us about the boundaries of Life and where we might find it in the Universe.
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Affiliation(s)
- James A Coker
- Department of Sciences, University of Maryland Global Campus, Adelphi, MD, USA
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Yao C, Sun J, Wang W, Zhuang Z, Liu J, Hao J. A novel cold-adapted β-galactosidase from Alteromonas sp. ML117 cleaves milk lactose effectively at low temperature. Process Biochem 2019. [DOI: 10.1016/j.procbio.2019.04.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Maruthamuthu M, van Elsas JD. Molecular cloning, expression, and characterization of four novel thermo-alkaliphilic enzymes retrieved from a metagenomic library. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:142. [PMID: 28588643 PMCID: PMC5457731 DOI: 10.1186/s13068-017-0808-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 04/29/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Enzyme discovery is a promising approach to aid in the deconstruction of recalcitrant plant biomass in an industrial process. Novel enzymes can be readily discovered by applying metagenomics on whole microbiomes. Our goal was to select, examine, and characterize eight novel glycoside hydrolases that were previously detected in metagenomic libraries, to serve biotechnological applications with high performance. RESULTS Here, eight glycosyl hydrolase family candidate genes were selected from metagenomes of wheat straw-degrading microbial consortia using molecular cloning and subsequent gene expression studies in Escherichia coli. Four of the eight enzymes had significant activities on either pNP-β-d-galactopyranoside, pNP-β-d-xylopyranoside, pNP-α-l-arabinopyranoside or pNP-α-d-glucopyranoside. These proteins, denoted as proteins 1, 2, 5 and 6, were his-tag purified and their nature and activities further characterized using molecular and activity screens with the pNP-labeled substrates. Proteins 1 and 2 showed high homologies with (1) a β-galactosidase (74%) and (2) a β-xylosidase (84%), whereas the remaining two (5 and 6) were homologous with proteins reported as a diguanylate cyclase and an aquaporin, respectively. The β-galactosidase- and β-xylosidase-like proteins 1 and 2 were confirmed as being responsible for previously found thermo-alkaliphilic glycosidase activities of extracts of E. coli carrying the respective source fosmids. Remarkably, the β-xylosidase-like protein 2 showed activities with both pNP-Xyl and pNP-Ara in the temperature range 40-50 °C and pH range 8.0-10.0. Moreover, proteins 5 and 6 showed thermotolerant α-glucosidase activity at pH 10.0. In silico structure prediction of protein 5 revealed the presence of a potential "GGDEF" catalytic site, encoding α-glucosidase activity, whereas that of protein 6 showed a "GDSL" site, encoding a 'new family' α-glucosidase activity. CONCLUSION Using a rational screening approach, we identified and characterized four thermo-alkaliphilic glycosyl hydrolases that have the potential to serve as constituents of enzyme cocktails that produce sugars from lignocellulosic plant remains.
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Affiliation(s)
- Mukil Maruthamuthu
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Jan Dirk van Elsas
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
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Santiago M, Ramírez-Sarmiento CA, Zamora RA, Parra LP. Discovery, Molecular Mechanisms, and Industrial Applications of Cold-Active Enzymes. Front Microbiol 2016; 7:1408. [PMID: 27667987 PMCID: PMC5016527 DOI: 10.3389/fmicb.2016.01408] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 08/25/2016] [Indexed: 11/17/2022] Open
Abstract
Cold-active enzymes constitute an attractive resource for biotechnological applications. Their high catalytic activity at temperatures below 25°C makes them excellent biocatalysts that eliminate the need of heating processes hampering the quality, sustainability, and cost-effectiveness of industrial production. Here we provide a review of the isolation and characterization of novel cold-active enzymes from microorganisms inhabiting different environments, including a revision of the latest techniques that have been used for accomplishing these paramount tasks. We address the progress made in the overexpression and purification of cold-adapted enzymes, the evolutionary and molecular basis of their high activity at low temperatures and the experimental and computational techniques used for their identification, along with protein engineering endeavors based on these observations to improve some of the properties of cold-adapted enzymes to better suit specific applications. We finally focus on examples of the evaluation of their potential use as biocatalysts under conditions that reproduce the challenges imposed by the use of solvents and additives in industrial processes and of the successful use of cold-adapted enzymes in biotechnological and industrial applications.
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Affiliation(s)
- Margarita Santiago
- Department of Chemical Engineering and Biotechnology, Centre for Biochemical Engineering and Biotechnology, Universidad de ChileSantiago, Chile
| | - César A. Ramírez-Sarmiento
- Schools of Engineering, Medicine and Biological Sciences, Institute for Biological and Medical Engineering, Pontificia Universidad Católica de ChileSantiago, Chile
| | - Ricardo A. Zamora
- Departamento de Biología, Facultad de Ciencias, Universidad de ChileSantiago, Chile
| | - Loreto P. Parra
- Schools of Engineering, Medicine and Biological Sciences, Institute for Biological and Medical Engineering, Pontificia Universidad Católica de ChileSantiago, Chile
- Department of Chemical and Bioprocesses Engineering, School of Engineering, Pontificia Universidad Católica de ChileSantiago, Chile
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Abstract
Biotechnology has almost unlimited potential to change our lives in very exciting ways. Many of the chemical reactions that produce these products can be fully optimized by performing them at extremes of temperature, pressure, salinity, and pH for efficient and cost-effective outcomes. Fortunately, there are many organisms (extremophiles) that thrive in extreme environments found in nature and offer an excellent source of replacement enzymes in lieu of mesophilic ones currently used in these processes. In this review, I discuss the current uses and some potential new applications of extremophiles and their products, including enzymes, in biotechnology.
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Affiliation(s)
- James A Coker
- Department of Biotechnology, University of Maryland, Adelphi, MD, USA
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Cold-Active β-Galactosidases: Sources, Biochemical Properties and Their Biotechnological Potential. BIOTECHNOLOGY OF EXTREMOPHILES: 2016. [DOI: 10.1007/978-3-319-13521-2_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Wang GX, Gao Y, Hu B, Lu XL, Liu XY, Jiao BH. A novel cold-adapted β-galactosidase isolated from Halomonas sp. S62: gene cloning, purification and enzymatic characterization. World J Microbiol Biotechnol 2013; 29:1473-80. [PMID: 23494630 DOI: 10.1007/s11274-013-1311-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Accepted: 03/07/2013] [Indexed: 11/28/2022]
Abstract
A novel 1,170 bp β-galactosidase gene sequence from Halomonas sp. S62 (BGalH) was identified through whole genome sequencing and was submitted to GenBank (Accession No. JQ337961). The BGalH gene was heterologously expressed in Escherichia coli BL21(DE3) cells, and the enzymatic properties of recombinant BGalH were studied. According to the polyacrylamide gel electrophoresis results and the sequence alignment analysis, BGalH is a dimeric protein and cannot be classified into one of the known β-galactosidase families (GH1, GH2, GH35, GH42). The optimal pH and temperature were determined to be 7.0 and 45 °C, respectively; the K m and K cat were 2.9 mM and 390.3 s(-1), respectively, for the reaction with the substrate ortho-nitrophenyl-β-D-galactopyranoside. At 0-20 °C, BGalH exhibited 50-70 % activity relative to its activity under the optimal conditions. BGalH was stable over a wide range of pHs (6.0-8.5) after a 1 h incubation (>93 % relative activity) and was thermostable at 50 °C and below (>60 % relative activity). The enzyme hydrolyzes lactose completely in milk over 24 h at 7 °C. The characteristics of this novel β-galactosidase suggest that BGalH may be a good candidate for medical researches and food industry applications.
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Affiliation(s)
- Guo-Xiang Wang
- Department of Biochemistry and Molecular Biology, Second Military Medical University, Shanghai 200433, China
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Variant of the Thermomyces lanuginosus lipase with improved kinetic stability: a candidate for enzyme replacement therapy. Biophys Chem 2013; 172:43-52. [PMID: 23357413 DOI: 10.1016/j.bpc.2012.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/08/2012] [Accepted: 12/08/2012] [Indexed: 11/21/2022]
Abstract
Lipases with high kinetic stability and enzymatic efficiency in the human gastro-intestinal tract may help against exocrine pancreatic insufficiency. Here we mimic gastric conditions to study how bile salts and pH affect the stability and activity of Thermomyces lanuginosus lipase (TlL) and its stabler variant StL using spectroscopy, calorimetry and gel electrophoresis. Both enzymes resist trypsin digestion with and without bile salts. Bile salts activate native TlL and StL equally well, bind weakly to denatured TlL and StL at lower pH and precipitate native TlL and StL at pH 4. StL refolds more efficiently than TlL from gastric pH in bile salts, regaining activity when refolding from pH as low as 1.8 and above while TlL cannot go below pH 2.6. StL also unfolds 10-40 fold more slowly in the denaturant guanidinium chloride and the anionic surfactant SDS. We ascribe StL's superior performance to general alterations in its electrostatic potential which makes it more acid-resistant. These superior properties make StL a good candidate for pancreatic enzyme replacement therapy.
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Horner T, Dunn M, Eggett D, Ogden L. β-Galactosidase activity of commercial lactase samples in raw and pasteurized milk at refrigerated temperatures. J Dairy Sci 2011; 94:3242-9. [DOI: 10.3168/jds.2010-3742] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 03/14/2011] [Indexed: 11/19/2022]
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Lactulose biosynthesis by β-galactosidase from a newly isolated Arthrobacter sp. J Ind Microbiol Biotechnol 2010; 38:471-6. [DOI: 10.1007/s10295-010-0897-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 10/29/2010] [Indexed: 10/18/2022]
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Gatti-Lafranconi P, Natalello A, Rehm S, Doglia SM, Pleiss J, Lotti M. Evolution of stability in a cold-active enzyme elicits specificity relaxation and highlights substrate-related effects on temperature adaptation. J Mol Biol 2009; 395:155-66. [PMID: 19850050 DOI: 10.1016/j.jmb.2009.10.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 10/08/2009] [Accepted: 10/14/2009] [Indexed: 10/20/2022]
Abstract
Molecular aspects of thermal adaptation of proteins were studied by following the co-evolution of temperature dependence, conformational stability, and substrate specificity in a cold-active lipase modified via directed evolution. We found that the evolution of kinetic stability was accompanied by a relaxation in substrate specificity. Moreover, temperature dependence and selectivity turned out to be mutually dependent. While the wild-type protein was strictly specific for short-chain triglycerides (C4) in the temperature range 10-50 degrees C and displayed highest activity in the cold, its stabilized variant was able to accept C8 and C12 molecules and its selectivity was temperature dependent. We could not detect any improvement in the overall structural robustness of the mutant when the structure was challenged by temperature or chemical denaturants. There is, however, strong evidence for local stabilization effects in the active-site region provided by two independent approaches. Differential scanning fluorimetry revealed that the exposure of hydrophobic patches (as the active site is) precedes denaturation, and molecular dynamics simulations confirmed that stability was obtained by restriction of the mobility of the lid, a flexible structure that regulates the access to the enzyme active site and influences its stability. This reduction of lid movements is suggested to be accompanied by a concomitant increase in the mobility of other protein regions, thus accounting for the observed broadening of substrate specificity.
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Affiliation(s)
- Pietro Gatti-Lafranconi
- Department of Biotechnology and Biosciences, State University of Milano-Bicocca, Piazza della Scienza 2, I-20126 Milano, Italy
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Sasaki M, Uno M, Akanuma S, Yamagishi A. Random mutagenesis improves the low-temperature activity of the tetrameric 3-isopropylmalate dehydrogenase from the hyperthermophile Sulfolobus tokodaii. Protein Eng Des Sel 2008; 21:721-7. [DOI: 10.1093/protein/gzn054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kennedy J, Marchesi JR, Dobson AD. Marine metagenomics: strategies for the discovery of novel enzymes with biotechnological applications from marine environments. Microb Cell Fact 2008; 7:27. [PMID: 18717988 PMCID: PMC2538500 DOI: 10.1186/1475-2859-7-27] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Accepted: 08/21/2008] [Indexed: 11/11/2022] Open
Abstract
Metagenomic based strategies have previously been successfully employed as powerful tools to isolate and identify enzymes with novel biocatalytic activities from the unculturable component of microbial communities from various terrestrial environmental niches. Both sequence based and function based screening approaches have been employed to identify genes encoding novel biocatalytic activities and metabolic pathways from metagenomic libraries. While much of the focus to date has centred on terrestrial based microbial ecosystems, it is clear that the marine environment has enormous microbial biodiversity that remains largely unstudied. Marine microbes are both extremely abundant and diverse; the environments they occupy likewise consist of very diverse niches. As culture-dependent methods have thus far resulted in the isolation of only a tiny percentage of the marine microbiota the application of metagenomic strategies holds great potential to study and exploit the enormous microbial biodiversity which is present within these marine environments.
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Affiliation(s)
- Jonathan Kennedy
- Environmental Research Institute, University College Cork, National University of Ireland, Lee Road, Cork, Ireland.
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Ferrer M, Golyshina O, Beloqui A, Golyshin PN. Mining enzymes from extreme environments. Curr Opin Microbiol 2007; 10:207-14. [PMID: 17548239 DOI: 10.1016/j.mib.2007.05.004] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 04/09/2007] [Accepted: 05/17/2007] [Indexed: 11/21/2022]
Abstract
Current advances in metagenomics have revolutionized the research in fields of microbial ecology and biotechnology, enabling not only a glimpse into the uncultured microbial population and mechanistic understanding of possible biogeochemical cycles and lifestyles of extreme organisms but also the high-throughput discovery of new enzymes for industrial bioconversions. Nowadays, the genetic and enzymatic differences across the gradients from 'neutral and pristine' to 'extreme and polluted' environments are well documented. Yet, extremophilic organisms are possibly the least well understood because our ability to study and understand their metabolic potential has been hampered by our inability to isolate pure cultures. There are at least two obstacles for reaping the fruit of the microbial diversity of extremophiles: first, in spite of the recent progress in development of new culturing techniques most extremophiles cannot be cultured using traditional culturing technologies; and second, the problem of the very low biomass densities often occurs under the conditions hostile for life, which often do not yield enough DNA and reduces the effectiveness of cloning.
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Affiliation(s)
- Manuel Ferrer
- Division of Applied Biocatalysis, Institute of Catalysis, CSIC, Cantoblanco, 28049 Madrid, Spain.
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