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Sousa J, Silvério SC, Costa AMA, Rodrigues LR. Metagenomic Approaches as a Tool to Unravel Promising Biocatalysts from Natural Resources: Soil and Water. Catalysts 2022; 12:385. [DOI: 10.3390/catal12040385] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Natural resources are considered a promising source of microorganisms responsible for producing biocatalysts with great relevance in several industrial areas. However, a significant fraction of the environmental microorganisms remains unknown or unexploited due to the limitations associated with their cultivation in the laboratory through classical techniques. Metagenomics has emerged as an innovative and strategic approach to explore these unculturable microorganisms through the analysis of DNA extracted from environmental samples. In this review, a detailed discussion is presented on the application of metagenomics to unravel the biotechnological potential of natural resources for the discovery of promising biocatalysts. An extensive bibliographic survey was carried out between 2010 and 2021, covering diverse metagenomic studies using soil and/or water samples from different types and locations. The review comprises, for the first time, an overview of the worldwide metagenomic studies performed in soil and water and provides a complete and global vision of the enzyme diversity associated with each specific environment.
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Ngara TR, Zhang H. Recent Advances in Function-based Metagenomic Screening. Genomics Proteomics Bioinformatics 2018; 16:405-415. [PMID: 30597257 PMCID: PMC6411959 DOI: 10.1016/j.gpb.2018.01.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/05/2018] [Accepted: 01/09/2018] [Indexed: 12/01/2022]
Abstract
Metagenomes from uncultured microorganisms are rich resources for novel enzyme genes. The methods used to screen the metagenomic libraries fall into two categories, which are based on sequence or function of the enzymes. The sequence-based approaches rely on the known sequences of the target gene families. In contrast, the function-based approaches do not involve the incorporation of metagenomic sequencing data and, therefore, may lead to the discovery of novel gene sequences with desired functions. In this review, we discuss the function-based screening strategies that have been used in the identification of enzymes from metagenomes. Because of its simplicity, agar plate screening is most commonly used in the identification of novel enzymes with diverse functions. Other screening methods with higher sensitivity are also employed, such as microtiter plate screening. Furthermore, several ultra-high-throughput methods were developed to deal with large metagenomic libraries. Among these are the FACS-based screening, droplet-based screening, and the in vivo reporter-based screening methods. The application of these novel screening strategies has increased the chance for the discovery of novel enzyme genes.
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Affiliation(s)
- Tanyaradzwa Rodgers Ngara
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, MOE Key Laboratory of Molecular Biophysics, Wuhan 430074, China
| | - Houjin Zhang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, MOE Key Laboratory of Molecular Biophysics, Wuhan 430074, China.
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Okano H, Hong X, Kanaya E, Angkawidjaja C, Kanaya S. Structural and biochemical characterization of a metagenome-derived esterase with a long N-terminal extension. Protein Sci 2014; 24:93-104. [PMID: 25348365 DOI: 10.1002/pro.2591] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 10/15/2014] [Accepted: 10/16/2014] [Indexed: 11/08/2022]
Abstract
The genes encoding six novel esterolytic/lipolytic enzymes, termed LC-Est1∼6, were isolated from a fosmid library of a leaf-branch compost metagenome by functional screening using tributyrin agar plates. These enzymes greatly vary in size and amino acid sequence. The highest identity between the amino acid sequence of each enzyme and that available from the database varies from 44 to 73%. Of these metagenome-derived enzymes, LC-Est1 is characterized by the presence of a long N-terminal extension (LNTE, residues 26-283) between a putative signal peptide (residues 1-25) and a C-terminal esterase domain (residues 284-510). A putative esterase from Candidatus Solibacter usitatus (CSu-Est) is the only protein, which shows the significant amino acid sequence identity (46%) to the entire region of LC-Est1. To examine whether LC-Est1 exhibits activity and its LNTE is important for activity and stability of the esterase domain, LC-Est1 (residues 26-510), LC-Est1C (residues 284-510), and LC-Est1C* (residues 304-510) were overproduced in E. coli, purified, and characterized. LC-Est1C* was only used for structural analysis. The crystal structure of LC-Est1C* highly resembles that of the catalytic domain of Thermotoga maritima esterase, suggesting that LNTE is not required for folding of the esterase domain. The enzymatic activity of LC-Est1C was lower than that of LC-Est1 by 60%, although its substrate specificity was similar to that of LC-Est1. LC-Est1C was less stable than LC-Est1 by 3.3°C. These results suggest that LNTE of LC-Est1 rather exists as an independent domain but is required for maximal activity and stability of the esterase domain.
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Affiliation(s)
- Hiroyuki Okano
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 565-0871, Japan
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Okano H, Ozaki M, Kanaya E, Kim JJ, Angkawidjaja C, Koga Y, Kanaya S. Structure and stability of metagenome-derived glycoside hydrolase family 12 cellulase (LC-CelA) a homolog of Cel12A from Rhodothermus marinus. FEBS Open Bio 2014; 4:936-46. [PMID: 25426413 PMCID: PMC4239480 DOI: 10.1016/j.fob.2014.10.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 10/27/2014] [Accepted: 10/27/2014] [Indexed: 11/24/2022] Open
Abstract
Ten novel cellulases, LC-CelA–J, were isolated from leaf–branch compost by a metagenomic approach. LC-CelA was characterized. The structure, activity, and stability of LC-CelA were similar to those of Cel12A from Rhodothermus marinus. Glu34-mediated hydrogen bonds and two disulfide bonds contribute to the stabilization of LC-CelA.
Ten genes encoding novel cellulases with putative signal peptides at the N-terminus, termed pre-LC-CelA–J, were isolated from a fosmid library of a leaf–branch compost metagenome by functional screening using agar plates containing carboxymethyl cellulose and trypan blue. All the cellulases except pre-LC-CelG have a 14–29 residue long flexible linker (FL) between the signal peptide and the catalytic domain. LC-CelA without a signal peptide (residues 20–261), which shows 76% amino acid sequence identity to Cel12A from Rhodothermus marinus (RmCel12A), was overproduced in Escherichiacoli, purified and characterized. LC-CelA exhibited its highest activity across a broad pH range (pH 5–9) and at 90 °C, indicating that LC-CelA is a highly thermostable cellulase, like RmCel12A. The crystal structure of LC-CelA was determined at 1.85 Å resolution and is nearly identical to that of RmCel12A determined in a form without the FL. Both proteins contain two disulfide bonds. LC-CelA has a 16-residue FL (residues 20–35), most of which is not visible in the electron density map, probably due to structural disorder. However, Glu34 and Pro35 form hydrogen bonds with the central region of the protein. ΔFL-LC-CelA (residues 36–261) and E34A-LC-CelA with a single Glu34 → Ala mutation were therefore constructed and characterized. ΔFL-LC-CelA and E34A-LC-CelA had lower melting temperatures (Tm) than LC-CelA by 14.7 and 12.0 °C respectively. The Tm of LC-CelA was also decreased by 28.0 °C in the presence of dithiothreitol. These results suggest that Glu34-mediated hydrogen bonds and the two disulfide bonds contribute to the stabilization of LC-CelA.
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Affiliation(s)
- Hiroyuki Okano
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masashi Ozaki
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Eiko Kanaya
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Joong-Jae Kim
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Clement Angkawidjaja
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan ; International College, Osaka University, 1-30 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Yuichi Koga
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shigenori Kanaya
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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Nguyen T, You D, Kanaya E, Koga Y, Kanaya S. Crystal structure of metagenome-derived LC9-RNase H1 with atypical DEDN active site motif. FEBS Lett 2013; 587:1418-23. [DOI: 10.1016/j.febslet.2013.03.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 03/09/2013] [Accepted: 03/11/2013] [Indexed: 11/19/2022]
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Nguyen TN, You DJ, Matsumoto H, Kanaya E, Koga Y, Kanaya S. Crystal structure of metagenome-derived LC11-RNase H1 in complex with RNA/DNA hybrid. J Struct Biol 2013; 182:144-54. [PMID: 23500886 DOI: 10.1016/j.jsb.2013.02.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 02/26/2013] [Accepted: 02/28/2013] [Indexed: 12/11/2022]
Abstract
LC11-RNase H1 is a Sulfolobus tokodaii RNase H1 (Sto-RNase H1) homologue isolated by metagenomic approach. In this study, the crystal structure of LC11-RNase H1 in complex with an RNA/DNA substrate was determined. Unlike Bacillus halodurans RNase H1 without hybrid binding domain (HBD) (Bh-RNase HC) and human RNase H1 without HBD (Hs-RNase HC), LC11-RNase H1 interacts with four non-consecutive 2'-OH groups of the RNA strand. The lack of interactions with four consecutive 2'-OH groups leads to a dramatic decrease in the ability of LC11-RNase H1 to cleave the DNA-RNA-DNA/DNA substrate containing four ribonucleotides as compared to those to cleave the substrates containing five and six ribonucleotides. The interaction of LC11-RNase H1 with the DNA strand is also different from those of Bh-RNase HC and Hs-RNase HC. Beside the common phosphate-binding pocket, LC11-RNase H1 has a unique DNA-binding channel. Furthermore, the active-site residues of LC11-RNase H1 are located farther away from the scissile phosphate group than those of Bh-RNase HC and Hs-RNase HC. Modeling of Sto-RNase H1 in complex with the 14bp RNA/DNA substrate, together with the structure-based mutational analyses, suggest that the ability of Sto-RNase H1 to cleave double-stranded RNA is dependent on the local conformation of the basic residues located at the DNA binding site.
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Affiliation(s)
- Tri-Nhan Nguyen
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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Nguyen TN, Angkawidjaja C, Kanaya E, Koga Y, Takano K, Kanaya S. Activity, stability, and structure of metagenome-derived LC11-RNase H1, a homolog of Sulfolobus tokodaii RNase H1. Protein Sci 2012; 21:553-61. [PMID: 22389131 DOI: 10.1002/pro.2043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 02/03/2012] [Accepted: 02/06/2012] [Indexed: 11/07/2022]
Abstract
Metagenome-derived LC11-RNase H1 is a homolog of Sulfolobus tokodaii RNase H1 (Sto-RNase H1). It lacks a C-terminal tail, which is responsible for hyperstabilization of Sto-RNase H1. Sto-RNase H1 is characterized by its ability to cleave not only an RNA/DNA hybrid but also a double-stranded RNA (dsRNA). To examine whether LC11-RNase H1 also exhibits both RNase H and dsRNase activities, LC11-RNase H1 was overproduced in Escherichia coli, purified, and characterized. LC11-RNase H1 exhibited RNase H activity with similar metal ion preference, optimum pH, and cleavage mode of substrate with those of Sto-RNase H1. However, LC11-RNase H1 did not exhibit dsRNase activity at any condition examined. LC11-RNase H1 was less stable than Sto-RNases H1 and its derivative lacking the C-terminal tail (Sto-RNase H1ΔC6) by 37 and 13 °C in T(m) , respectively. To understand the structural bases for these differences, the crystal structure of LC11-RNase H1 was determined at 1.4 Å resolution. The LC11-RNase H1 structure is highly similar to the Sto-RNase H1 structure. However, LC11-RNase H1 has two grooves on protein surface, one containing the active site and the other containing DNA-phosphate binding pocket, while Sto-RNase H1 has one groove containing the active site. In addition, LC11-RNase H1 contains more cavities and buried charged residues than Sto-RNase H1. We propose that LC11-RNase H1 does not exhibit dsRNase activity because dsRNA cannot fit to the two grooves on protein surface and that LC11-RNase H1 is less stable than Sto-RNase H1ΔC6 because of the increase in cavity volume and number of buried charged residues.
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Affiliation(s)
- Tri-Nhan Nguyen
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
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Jongruja N, You DJ, Kanaya E, Koga Y, Takano K, Kanaya S. The N-terminal hybrid binding domain of RNase HI from Thermotoga maritima is important for substrate binding and Mg2+-dependent activity. FEBS J 2010; 277:4474-89. [DOI: 10.1111/j.1742-4658.2010.07834.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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