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Ji S, Gavande PV, Choudhury B, Goyal A. Computational design and structure dynamics analysis of bifunctional chimera of endoxylanase from Clostridium thermocellum and xylosidase from Bacteroides ovatus. 3 Biotech 2023; 13:59. [PMID: 36714550 PMCID: PMC9877272 DOI: 10.1007/s13205-023-03482-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 01/13/2023] [Indexed: 01/26/2023] Open
Abstract
Development of chimeric enzymes by protein engineering can more efficiently contribute toward biomass conversion for bioenergy generation. Therefore, prior to experimental validation, a computational approach by modeling and molecular dynamic simulation can assess the structural and functional behavior of chimeric enzymes. In this study, a bifunctional chimera, CtXyn11A-BoGH43A comprising an efficient endoxylanase (CtXyn11A) from Clostridium thermocellum and xylosidase (BoGH43A) from Bacteroides ovatus was computationally designed and its binding and stability analysis with xylooligosaccharides were performed. The modeled chimera showed β-jellyroll fold for CtXyn11A and 5-bladed β-propeller fold for BoGH43A module. Stereo-chemical properties analyzed by Ramachandran plot showed 98.8% residues in allowed region, validating the modeled chimera. The catalytic residues identified by multiple sequence alignment were Glu94 and Glu184 for CtXyn11A and Asp229 and Glu384 for BoGH43A modules. CtXyn11A followed retaining-type, whereas BoGH43A enforced inverting-type of reaction mechanism during xylan hydrolysis as revealed by superposition and GH11 and GH43 familial analyses. Molecular docking studies showed binding energy, (ΔG) - 4.54 and - 4.18 kcal/mol for CtXyn11A and BoGH43A modules of chimera, respectively, with xylobiose, while - 3.94 and - 3.82 kcal/mol for CtXyn11A and BoGH43A modules of chimera, respectively, with xylotriose. MD simulation of CtXyn11A-BoGH43A complexed with xylobiose and xylotriose till 100 ns displayed stability by RMSD, compactness by R g and conformational stability by SASA analyses. The lowered values of RMSF in active-site residues, Glu94, Glu184, Asp229, Asp335 and Glu384 confirmed the efficient binding of chimera with xylobiose and xylotriose. These results were in agreement with the earlier experimental studies on CtXyn11A releasing xylooligosaccharides from xylan and BoGH43A releasing d-xylose from xylooligosaccharides and xylobiose. The chimera showed stronger affinity in terms of total short-range interaction energy; - 190 and - 121 kJ/mol for with xylobiose and xylotriose, respectively. The bifunctional chimera, CtXyn11A-BoGH43A showed stability and integrity with xylobiose and xylotriose. The designed chimera can be constructed and applied for efficient biomass conversion.
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Affiliation(s)
- Shyam Ji
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039 India
| | - Parmeshwar Vitthal Gavande
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039 India
| | - Bipasha Choudhury
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039 India
| | - Arun Goyal
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039 India
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Liu Y, Angelov A, Feiler W, Baudrexl M, Zverlov V, Liebl W, Vanderhaeghen S. Arabinan saccharification by biogas reactor metagenome-derived arabinosyl hydrolases. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:121. [PMID: 36371193 PMCID: PMC9655821 DOI: 10.1186/s13068-022-02216-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Plant cell walls represent the most plentiful renewable organic resource on earth, but due to their heterogeneity, complex structure and partial recalcitrance, their use as biotechnological feedstock is still limited. RESULTS In order to identify efficient enzymes for polysaccharide breakdown, we have carried out functional screening of metagenomic fosmid libraries from biogas fermenter microbial communities grown on sugar beet pulp, an arabinan-rich agricultural residue, or other sources containing microbes that efficiently depolymerize polysaccharides, using CPH (chromogenic polysaccharide hydrogel) or ICB (insoluble chromogenic biomass) labeled polysaccharide substrates. Seventy-one depolymerase-encoding genes were identified from 55 active fosmid clones by using Illumina and Sanger sequencing and dbCAN CAZyme (carbohydrate-active enzyme) annotation. An around 56 kb assembled DNA fragment putatively originating from Xylanivirga thermophila strain or a close relative was analyzed in detail. It contained 48 ORFs (open reading frames), of which 31 were assigned to sugar metabolism. Interestingly, a large number of genes for enzymes putatively involved in degradation and utilization of arabinose-containing carbohydrates were found. Seven putative arabinosyl hydrolases from this DNA fragment belonging to glycoside hydrolase (GH) families GH51 and GH43 were biochemically characterized, revealing two with endo-arabinanase activity and four with exo-α-L-arabinofuranosidase activity but with complementary cleavage properties. These enzymes were found to act synergistically and can completely hydrolyze SBA (sugar beet arabinan) and DA (debranched arabinan). CONCLUSIONS We screened 32,776 fosmid clones from several metagenomic libraries with chromogenic lignocellulosic substrates for functional enzymes to advance the understanding about the saccharification of recalcitrant lignocellulose. Seven putative X. thermophila arabinosyl hydrolases were characterized for pectic substrate degradation. The arabinosyl hydrolases displayed maximum activity and significant long-term stability around 50 °C. The enzyme cocktails composed in this study fully degraded the arabinan substrates and thus could serve for arabinose production in food and biofuel industries.
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Affiliation(s)
- Yajing Liu
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
- Present Address: Chair of Chemistry of Biogenic Resources, Technical University of Munich, Schulgasse 16, 94315 Straubing, Germany
| | - Angel Angelov
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
- Present Address: NGS Competence Center Tübingen, Universitätsklinikum Tübingen, Calwerstraße 7, 72076 Tübingen, Germany
| | - Werner Feiler
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Melanie Baudrexl
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Vladimir Zverlov
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Wolfgang Liebl
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Sonja Vanderhaeghen
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
- Present Address: IMGM Laboratories, Lochhamer Straße 29a, 82152 Planegg, Germany
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Verma D, Satyanarayana T. Xylanolytic Extremozymes Retrieved From Environmental Metagenomes: Characteristics, Genetic Engineering, and Applications. Front Microbiol 2020; 11:551109. [PMID: 33042057 PMCID: PMC7527525 DOI: 10.3389/fmicb.2020.551109] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 08/21/2020] [Indexed: 01/29/2023] Open
Abstract
Xylanolytic enzymes have extensive applications in paper, food, and feed, pharmaceutical, and biofuel industries. These industries demand xylanases that are functional under extreme conditions, such as high temperature, acidic/alkaline pH, and others, which are prevailing in bioprocessing industries. Despite the availability of several xylan-hydrolyzing enzymes from cultured microbes, there is a huge gap between what is available and what industries require. DNA manipulations as well as protein-engineering techniques are also not quite satisfactory in generating xylan-hydrolyzing extremozymes. With a compound annual growth rate of 6.6% of xylan-hydrolyzing enzymes in the global market, there is a need for xylanolytic extremozymes. Therefore, metagenomic approaches have been employed to uncover hidden xylanolytic genes that were earlier inaccessible in culture-dependent approaches. Appreciable success has been achieved in retrieving several unusual xylanolytic enzymes with novel and desirable characteristics from different extreme environments using functional and sequence-based metagenomic approaches. Moreover, the Carbohydrate Active Enzymes database includes approximately 400 GH-10 and GH-11 unclassified xylanases. This review discusses sources, characteristics, and applications of xylanolytic enzymes obtained through metagenomic approaches and their amelioration by genetic engineering techniques.
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Affiliation(s)
- Digvijay Verma
- Department of Microbiology, Babasaheb Bhimrao Ambedkar (Central) University, Lucknow, India
| | - Tulasi Satyanarayana
- Department of Biological Sciences and Engineering, Netaji Subhas University of Technology, Dwarka, New Delhi, India
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Poria V, Saini JK, Singh S, Nain L, Kuhad RC. Arabinofuranosidases: Characteristics, microbial production, and potential in waste valorization and industrial applications. BIORESOURCE TECHNOLOGY 2020; 304:123019. [PMID: 32089440 DOI: 10.1016/j.biortech.2020.123019] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 02/09/2020] [Accepted: 02/11/2020] [Indexed: 05/15/2023]
Abstract
Alpha-L-arabinofuranoside arabinofuranohydrolase (ARA), more commonly known as alpha-L-arabinofuranosidase (E.C. number 3.2.1.55), is a hydrolytic enzyme, catalyzing the cleavage of alpha-L-arabinose by acting on the non-reducing ends of alpha-L-arabinofuranosides, alpha-L-arabinans containing (1,3)- and/or (1,5)-linked arabinoxylans and arabinogalactans. ARA functions as debranching enzyme removing arabinose substituents from arabinoxylan and arabinoxylooligomers, thereby, boosting the hydrolysis of arabinoxylan fraction of hemicellulose and improving bioconversion of lignocellulosic biomass. Previously, comprehensive information on this enzyme has not been reviewed thoroughly. Therefore, the main aim of this review is to highlight the important properties of this interesting enzyme, microorganisms used for its production, and enhanced production using genetic engineering approach. An account on synergism with other biomass hydrolyzing enzymes and various industrial applications of this enzyme has also been provided along with an outlook on further research and development.
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Affiliation(s)
- Vikram Poria
- Department of Microbiology, Central University of Haryana, Mahendergarh, Haryana PIN-123031, India
| | - Jitendra Kumar Saini
- Department of Microbiology, Central University of Haryana, Mahendergarh, Haryana PIN-123031, India
| | - Surender Singh
- Department of Microbiology, Central University of Haryana, Mahendergarh, Haryana PIN-123031, India; Division of Microbiology, Indian Agricultural Research Institute, New Delhi PIN-110012, India.
| | - Lata Nain
- Division of Microbiology, Indian Agricultural Research Institute, New Delhi PIN-110012, India
| | - Ramesh Chander Kuhad
- Central University of Haryana, Mahendergarh, Haryana PIN-123031, India; Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, New Delhi PIN-110021, India
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Romanò C, Jiang H, Boos I, Clausen MH. S-Glycosides: synthesis of S-linked arabinoxylan oligosaccharides. Org Biomol Chem 2020; 18:2696-2701. [PMID: 32206767 DOI: 10.1039/d0ob00470g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
S-Glycosides are important tools for the elucidation of specific protein-carbohydrate interactions and can significantly aid structural and functional studies of carbohydrate-active enzymes, as they are often inert or act as enzyme inhibitors. In this context, this work focuses on the introduction of an S-linkage into arabinoxylan oligosaccharides (AXs) in order to obtain a small collection of synthetic tools for the study of AXs degrading enzymes. The key step for the introduction of the S-glycosidic linkage involved anomeric thiol S-alkylation of an orthogonally protected l-arabinopyranoside triflate. The resulting S-linked disaccharide was subsequently employed in a series of glycosylation reactions to obtain a selectively protected tetrasaccharide. This could be further elaborated through chemoselective deprotection and glycosylation reactions to introduce branching l-arabinofuranosides.
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Affiliation(s)
- Cecilia Romanò
- Center for Nanomedicine & Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kgs. Lyngby, Denmark.
| | - Hao Jiang
- Center for Nanomedicine & Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kgs. Lyngby, Denmark.
| | - Irene Boos
- Center for Nanomedicine & Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kgs. Lyngby, Denmark.
| | - Mads H Clausen
- Center for Nanomedicine & Theranostics, Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kgs. Lyngby, Denmark.
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β-Xylosidases: Structural Diversity, Catalytic Mechanism, and Inhibition by Monosaccharides. Int J Mol Sci 2019; 20:ijms20225524. [PMID: 31698702 PMCID: PMC6887791 DOI: 10.3390/ijms20225524] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/02/2019] [Accepted: 11/04/2019] [Indexed: 12/20/2022] Open
Abstract
Xylan, a prominent component of cellulosic biomass, has a high potential for degradation into reducing sugars, and subsequent conversion into bioethanol. This process requires a range of xylanolytic enzymes. Among them, β-xylosidases are crucial, because they hydrolyze more glycosidic bonds than any of the other xylanolytic enzymes. They also enhance the efficiency of the process by degrading xylooligosaccharides, which are potent inhibitors of other hemicellulose-/xylan-converting enzymes. On the other hand, the β-xylosidase itself is also inhibited by monosaccharides that may be generated in high concentrations during the saccharification process. Structurally, β-xylosidases are diverse enzymes with different substrate specificities and enzyme mechanisms. Here, we review the structural diversity and catalytic mechanisms of β-xylosidases, and discuss their inhibition by monosaccharides.
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Fortune B, Mhlongo S, van Zyl LJ, Huddy R, Smart M, Trindade M. Characterisation of three novel α-L-arabinofuranosidases from a compost metagenome. BMC Biotechnol 2019; 19:22. [PMID: 30999885 PMCID: PMC6472066 DOI: 10.1186/s12896-019-0510-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 03/13/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The importance of the accessory enzymes such as α-L-arabinofuranosidases (AFases) in synergistic interactions within cellulolytic mixtures has introduced a paradigm shift in the search for hydrolytic enzymes. The aim of this study was to characterize novel AFase genes encoding enzymes with differing temperature optima and thermostabilities for use in hydrolytic cocktails. RESULTS Three fosmids, pFos-H4, E3 and D3 were selected from the cloned metagenome of high temperature compost, expressed in Escherichia coli and subsequently purified to homogeneity from cell lysate. All the AFases were clustered within the GH51 AFase family and shared a homo-hexameric structure. Both AFase-E3 and H4 showed optimal activity at 60 °C while AFase-D3 had unique properties as it showed optimal activity at 25 °C as well as the ability to maintain substantial activity at temperatures as high as 90 °C. However, AFase-E3 was the most thermostable amongst the three AFases showing full activity even at 70 °C. The maximum activity was observed at a pH profile between pH 4.0-6.0 for all three AFases with optimal activity for AFase H4, D3 and E3 at pH 5.0, 4.5 and 4.0, respectively. All the AFases showed KM range between 0.31 mM and 0.43 mM, Kcat range between 131 s- 1 and 219 s- 1 and the specific activity for AFase-H4, AFases-E3 and was 143, 228 and 175 U/mg, respectively. AFases-E3 and D3 displayed activities against pNP-β-L-arabinopyranoside and pNP-β-L-mannopyranoside respectively, and both hydrolysed pNP-β-D-glucopyranoside. CONCLUSION All three AFases displayed different biochemical characteristics despite all showing conserved overall structural similarity with typical domains of AFases belonging to GH51 family. The hydrolysis of cellobiose by a GH51 family AFase is demonstrated for the first time in this study.
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Affiliation(s)
- Brent Fortune
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, Bellville, South Africa
| | - Sizwe Mhlongo
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, Bellville, South Africa
| | - Leonardo Joaquim van Zyl
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, Bellville, South Africa
| | - Robert Huddy
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, Bellville, South Africa.,Centre for Bioprocess Engineering Research, University of Cape Town, Cape Town, Western Cape, South Africa
| | - Mariette Smart
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, Bellville, South Africa.,Centre for Bioprocess Engineering Research, University of Cape Town, Cape Town, Western Cape, South Africa
| | - Marla Trindade
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, Bellville, South Africa.
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Ray S, Vigouroux J, Bouder A, Francin Allami M, Geairon A, Fanuel M, Ropartz D, Helbert W, Lahaye M, Bonnin E. Functional exploration of Pseudoalteromonas atlantica as a source of hemicellulose-active enzymes: Evidence for a GH8 xylanase with unusual mode of action. Enzyme Microb Technol 2019; 127:6-16. [PMID: 31088618 DOI: 10.1016/j.enzmictec.2019.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/26/2019] [Accepted: 04/07/2019] [Indexed: 11/18/2022]
Abstract
To address the need for efficient enzymes exhibiting novel activities towards cell wall polysaccharides, the bacterium Pseudoalteromonas atlantica was selected based on the presence of potential hemicellulases in its annotated genome. It was grown in the presence or not of hemicelluloses and the culture filtrates were screened towards 42 polysaccharides. P. atlantica showed appreciable diversity of enzymes active towards hemicelluloses from Monocot and Dicot origin, in agreement with its genome annotation. After growth on beechwood glucuronoxylan and fractionation of the secretome, a β-xylosidase, a α-arabinofuranosidase and an acetylesterase activities were evidenced. A GH8 enzyme obtained in the same growth conditions was further cloned and heterologously overexpressed. It was shown to be a xylanase active on heteroxylans from various sources. The detailed study of its mode of action demonstrated that the oligosaccharides produced carried a long tail of un-substituted xylose residues on the reducing end.
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Affiliation(s)
- Sayani Ray
- INRA, UR 1268 Biopolymères - Interactions - Assemblages, 44 316 Nantes, France; Department of Chemistry, The University of Burdwan, Burdwan, 713104 West Bengal, India
| | | | - Axelle Bouder
- INRA, UR 1268 Biopolymères - Interactions - Assemblages, 44 316 Nantes, France
| | | | - Audrey Geairon
- INRA, UR 1268 Biopolymères - Interactions - Assemblages, 44 316 Nantes, France
| | - Mathieu Fanuel
- INRA, UR 1268 Biopolymères - Interactions - Assemblages, 44 316 Nantes, France
| | - David Ropartz
- INRA, UR 1268 Biopolymères - Interactions - Assemblages, 44 316 Nantes, France
| | - William Helbert
- CERMAV-CNRS, 601 rue de la Chimie, BP53, 38041 Grenoble, France
| | - Marc Lahaye
- INRA, UR 1268 Biopolymères - Interactions - Assemblages, 44 316 Nantes, France
| | - Estelle Bonnin
- INRA, UR 1268 Biopolymères - Interactions - Assemblages, 44 316 Nantes, France.
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Affiliation(s)
- Csaba Fehér
- Department of Applied Biotechnology and Food Science, Biorefinery Research Group, Budapest University of Technology and Economics, Budapest, Hungary
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EcXyl43 β-xylosidase: molecular modeling, activity on natural and artificial substrates, and synergism with endoxylanases for lignocellulose deconstruction. Appl Microbiol Biotechnol 2018; 102:6959-6971. [PMID: 29876606 DOI: 10.1007/s00253-018-9138-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/10/2018] [Accepted: 05/15/2018] [Indexed: 10/14/2022]
Abstract
Biomass hydrolysis constitutes a bottleneck for the biotransformation of lignocellulosic residues into bioethanol and high-value products. The efficient deconstruction of polysaccharides to fermentable sugars requires multiple enzymes acting concertedly. GH43 β-xylosidases are among the most interesting enzymes involved in hemicellulose deconstruction into xylose. In this work, the structural and functional properties of β-xylosidase EcXyl43 from Enterobacter sp. were thoroughly characterized. Molecular modeling suggested a 3D structure formed by a conserved N-terminal catalytic domain linked to an ancillary C-terminal domain. Both domains resulted essential for enzymatic activity, and the role of critical residues, from the catalytic and the ancillary modules, was confirmed by mutagenesis. EcXyl43 presented β-xylosidase activity towards natural and artificial substrates while arabinofuranosidase activity was only detected on nitrophenyl α-L-arabinofuranoside (pNPA). It hydrolyzed xylobiose and purified xylooligosaccharides (XOS), up to degree of polymerization 6, with higher activity towards longer XOS. Low levels of activity on commercial xylan were also observed, mainly on the soluble fraction. The addition of EcXyl43 to GH10 and GH11 endoxylanases increased the release of xylose from xylan and pre-treated wheat straw. Additionally, EcXyl43 exhibited high efficiency and thermal stability under its optimal conditions (40 °C, pH 6.5), with a half-life of 58 h. Therefore, this enzyme could be a suitable additive for hemicellulases in long-term hydrolysis reactions. Because of its moderate inhibition by monomeric sugars but its high inhibition by ethanol, EcXyl43 could be particularly more useful in separate hydrolysis and fermentation (SHF) than in simultaneous saccharification and co-fermentation (SSCF) or consolidated bioprocessing (CBP).
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11
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Identification and characterization of the first β-1,3-d-xylosidase from a gram-positive bacterium, Streptomyces sp. SWU10. Enzyme Microb Technol 2017; 112:72-78. [PMID: 29499784 DOI: 10.1016/j.enzmictec.2017.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/06/2017] [Accepted: 11/07/2017] [Indexed: 11/21/2022]
Abstract
In previous reports, we characterized four endo-xylanases produced by Streptomyces sp. strain SWU10 that degrade xylans to several xylooligosaccharides. To obtain a set of enzymes to achieve complete xylan degradation, a β-d-xylosidase gene was cloned and expressed in Escherichia coli, and the recombinant protein, named rSWU43A, was characterized. SWU43A is composed of 522 amino acids and does not contain a signal peptide, indicating that the enzyme is an intracellular protein. SWU43A was revealed to contain a Glyco_hydro_43 domain and possess the three conserved amino acid residues of the glycoside hydrolase family 43 proteins. The molecular mass of rSWU43A purified by Ni-affinity column chromatography was estimated to be 60kDa. The optimum reaction conditions of rSWU43A were pH 6.5 and 40°C. The enzyme was stable up to 40°C over a wide pH range (3.1-8.9). rSWU43A activity was enhanced by Fe2+ and Mn2+ and inhibited by various metals (Ag+, Cd2+, Co2+, Cu2+, Hg2+, Ni2+, and Zn2+), d-xylose, and l-arabinose. rSWU43A showed activity on p-nitrophenyl-β-d-xylopyranoside and p-nitrophenyl-α-l-arabinofuranoside substrates, with specific activities of 0.09 and 0.06U/mg, respectively, but not on any xylosidic or arabinosidic polymers. rSWU43A efficiently degraded β-1,3-xylooligosaccharides to produce xylose but showed little activity towards β-1,4-xylobiose, with specific activities of 1.33 and 0.003U/mg, respectively. These results demonstrate that SWU43A is a β-1,3-d-xylosidase (EC 3.2.1.72), which to date has only been described in the marine bacterium Vibrio sp. Therefore, rSWU43A of Streptomyces sp. is the first β-1,3-xylosidase found in gram-positive bacteria. SWU43A could be useful as a specific tool for the structural elucidation and production of xylose from β-1,3-xylan in seaweed cell walls.
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Orita T, Sakka M, Kimura T, Sakka K. Characterization of Ruminiclostridium josui arabinoxylan arabinofuranohydrolase, RjAxh43B, and RjAxh43B-containing xylanolytic complex. Enzyme Microb Technol 2017. [DOI: 10.1016/j.enzmictec.2017.05.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Schendel RR, Puchbauer AK, Bunzel M. Glycoside Hydrolase Family 51 α-l-Arabinofuranosidases fromClostridium thermocellumandCellvibrio japonicusReleaseO–5-Feruloylated Arabinose. Cereal Chem 2016. [DOI: 10.1094/cchem-01-16-0011-n] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Rachel R. Schendel
- Karlsruhe Institute of Technology (KIT), Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Adenauerring 20A, 76131 Karlsruhe, Germany
| | - Ann-Katrin Puchbauer
- Karlsruhe Institute of Technology (KIT), Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Adenauerring 20A, 76131 Karlsruhe, Germany
| | - Mirko Bunzel
- Karlsruhe Institute of Technology (KIT), Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Adenauerring 20A, 76131 Karlsruhe, Germany
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Matsuzawa T, Kaneko S, Yaoi K. Screening, identification, and characterization of a GH43 family β-xylosidase/α-arabinofuranosidase from a compost microbial metagenome. Appl Microbiol Biotechnol 2015; 99:8943-54. [DOI: 10.1007/s00253-015-6647-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/09/2015] [Accepted: 04/19/2015] [Indexed: 01/09/2023]
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15
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Sae-Lee R, Boonmee A. Newly derived GH43 gene from compost metagenome showing dual xylanase and cellulase activities. Folia Microbiol (Praha) 2014; 59:409-17. [PMID: 24737296 DOI: 10.1007/s12223-014-0313-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 03/05/2014] [Indexed: 10/25/2022]
Abstract
A metagenomic fosmid library was constructed from compost microbial communities that were collected from various farms throughout the Khon Kaen province, Thailand. The library was enriched in carboxymethylcellulose (CM-cellulose)--containing media prior to the screening of clones capable of degrading cellulosic materials. Two clones were selected for further subcloning and sequencing based on different patterns from restriction analysis. Deduced amino acid analysis of possible ORFs revealed one novel gene encoding an enzyme belonging to glycosyl hydrolase family 43 (GH43), which is a GH family rarely found in metagenomic studies. The most notable finding is that this enzyme, designated as Biof1_09, shows dual activities, namely endocellulase and endoxylanase activities. Biof1_09 showed greater than 50% of its activity under acidic conditions ranging from pH 3.5 to 5.5 with a pH optimum of 4.5. The optimum temperature of this enzyme was between 45 and 55 °C with an optimum of 50 °C. The properties of Biof1_09 make this enzyme an attractive candidate for large-scale expression for use in lignocellulose degradation for various bioprocess applications, including bioethanol fermentation.
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Affiliation(s)
- Ritthironk Sae-Lee
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand
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β-xylosidases and α-L-arabinofuranosidases: accessory enzymes for arabinoxylan degradation. Biotechnol Adv 2013; 32:316-32. [PMID: 24239877 DOI: 10.1016/j.biotechadv.2013.11.005] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 10/28/2013] [Accepted: 11/09/2013] [Indexed: 11/22/2022]
Abstract
Arabinoxylan (AX) is among the most abundant hemicelluloses on earth and one of the major components of feedstocks that are currently investigated as a source for advanced biofuels. As global research into these sustainable biofuels is increasing, scientific knowledge about the enzymatic breakdown of AX advanced significantly over the last decade. This review focuses on the exo-acting AX hydrolases, such as α-arabinofuranosidases and β-xylosidases. It aims to provide a comprehensive overview of the diverse substrate specificities and corresponding structural features found in the different glycoside hydrolase families. A careful review of the available literature reveals a marked difference in activity between synthetically labeled and naturally occurring substrates, often leading to erroneous enzymatic annotations. Therefore, special attention is given to enzymes with experimental evidence on the hydrolysis of natural polymers.
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The ability of bifidobacteria to degrade arabinoxylan oligosaccharide constituents and derived oligosaccharides is strain dependent. Appl Environ Microbiol 2013; 80:204-17. [PMID: 24141124 DOI: 10.1128/aem.02853-13] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Arabinoxylan oligosaccharides (AXOS) are prebiotic carbohydrates with promising health-promoting properties that stimulate the activity of specific colon bacteria, in particular bifidobacteria. However, the mechanisms by which bifidobacterial strains break down these compounds in the colon is still unknown. This study investigates AXOS consumption of a large number of bifidobacterial strains (36), belonging to 11 different species, systematically. To determine their degradation mechanisms, all strains were grown on a mixture of arabinose and xylose, xylo-oligosaccharides, and complex AXOS molecules as the sole added energy sources. Based on principal component and cluster analyses of their different arabinose substituent and/or xylose backbone consumption patterns, five clusters that were species independent could be distinguished among the bifidobacterial strains tested. In parallel, the strains were screened for the presence of genes encoding several putative AXOS-degrading enzymes, but no clear-cut correlation could be made with the different degradation mechanisms. The intra- and interspecies differences in the consumption patterns of AXOS indicate that bifidobacterial strains could avoid competition among each other or even could cooperate jointly to degrade these complex prebiotics. The knowledge gained on the AXOS degradation mechanisms in bifidobacteria can be of importance in the rational design of prebiotics with tailor-made composition and thus increased specificity in the colon.
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Jordan DB, Vermillion KE, Grigorescu AA, Braker JD. Rehabilitation of faulty kinetic determinations and misassigned glycoside hydrolase family of retaining mechanism β-xylosidases. Arch Biochem Biophys 2013; 537:176-84. [PMID: 23916587 DOI: 10.1016/j.abb.2013.07.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 11/16/2022]
Abstract
We obtained Cx1 from a commercial supplier, whose catalog listed it as a β-xylosidase of glycoside hydrolase family 43. NMR experiments indicate retention of anomeric configuration in its reaction stereochemistry, opposing the assignment of GH43, which follows an inverting mechanism. Partial protein sequencing indicates Cx1 is similar to but not identical to β-xylosidases of GH52, including Q09LZ0, that have retaining mechanisms. Q09LZ0 β-xylosidase had been characterized biochemically in kinetic reactions that contained Tris. We overproduced Q09LZ0 and demonstrated that Tris is a competitive inhibitor of the β-xylosidase. Also, the previous work used grossly incorrect extinction coefficients for product 4-nitrophenol. We redetermined kinetic parameters using reactions that omitted Tris and using correct extinction coefficients for 4-nitrophenol. Cx1 and Q09LZ0 β-xylosidases were thus shown to possess similar kinetic properties when acting on 4-nitrophenyl-β-d-xylopyranoside and xylobiose. kcat pH profiles of Cx1 and Q09LZ0 acting on 4-nitrophenyl-β-d-xylopyranoside and xylobiose have patterns containing two rate increases with increasing acidity, not reported before for glycoside hydrolases. The dexylosylation step of 4-nitrophenyl-β-d-xylopyranoside hydrolysis mediated by Q09LZ0 is not rate determining for kcat(4NPX).
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Affiliation(s)
- Douglas B Jordan
- USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604, USA.
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Viborg AH, Sørensen KI, Gilad O, Steen-Jensen DB, Dilokpimol A, Jacobsen S, Svensson B. Biochemical and kinetic characterisation of a novel xylooligosaccharide-upregulated GH43 β-d-xylosidase/α-l-arabinofuranosidase (BXA43) from the probiotic Bifidobacterium animalis subsp. lactis BB-12. AMB Express 2013; 3:56. [PMID: 24025736 PMCID: PMC3847938 DOI: 10.1186/2191-0855-3-56] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/02/2013] [Indexed: 12/28/2022] Open
Abstract
The Bifidobacterium animalis subsp. lactis BB-12 gene BIF_00092, assigned to encode a β-d-xylosidase (BXA43) of glycoside hydrolase family 43 (GH43), was cloned with a C-terminal His-tag and expressed in Escherichia coli. BXA43 was purified to homogeneity from the cell lysate and found to be a dual-specificity exo-hydrolase active on para-nitrophenyl-β-d-xylopyranoside (pNPX), para-nitrophenyl-α-L-arabinofuranoside (pNPA), β-(1 → 4)-xylopyranosyl oligomers (XOS) of degree of polymerisation (DP) 2-4, and birchwood xylan. A phylogenetic tree of the 92 characterised GH43 enzymes displayed five distinct groups (I - V) showing specificity differences. BXA43 belonged to group IV and had an activity ratio for pNPA:pNPX of 1:25. BXA43 was stable below 40°C and at pH 4.0-8.0 and showed maximum activity at pH 5.5 and 50°C. Km and kcat for pNPX were 15.6 ± 4.2 mM and 60.6 ± 10.8 s-1, respectively, and substrate inhibition became apparent above 18 mM pNPX. Similar kinetic parameters and catalytic efficiency values were reported for β-d-xylosidase (XynB3) from Geobacillus stearothermophilus T‒6 also belonging to group IV. The activity of BXA43 for xylooligosaccharides increased with the size and was 2.3 and 5.6 fold higher, respectively for xylobiose and xylotetraose compared to pNPX. BXA43 showed clearly metal inhibition for Zn2+ and Ag+, which is different to its close homologues. Multiple sequence alignment and homology modelling indicated that Arg505Tyr506 present in BXA43 are probably important for binding to xylotetraose at subsite +3 and occur only in GH43 from the Bifidobacterium genus.
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Affiliation(s)
- Alexander Holm Viborg
- Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kgs, Lyngby, Denmark
| | - Kim Ib Sørensen
- Department for Strains, Chr. Hansen A/S, 2970 Hørsholm, Denmark
| | - Ofir Gilad
- Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kgs, Lyngby, Denmark
- Department for Identification, Chr. Hansen A/S, 2970 Hørsholm, Denmark
| | - Daniel Bisgaard Steen-Jensen
- Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kgs, Lyngby, Denmark
| | - Adiphol Dilokpimol
- Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kgs, Lyngby, Denmark
| | - Susanne Jacobsen
- Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kgs, Lyngby, Denmark
| | - Birte Svensson
- Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kgs, Lyngby, Denmark
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Gruninger RJ, Gong X, Forster RJ, McAllister TA. Biochemical and kinetic characterization of the multifunctional β-glucosidase/β-xylosidase/α-arabinosidase, Bgxa1. Appl Microbiol Biotechnol 2013; 98:3003-12. [DOI: 10.1007/s00253-013-5191-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/06/2013] [Accepted: 08/11/2013] [Indexed: 12/28/2022]
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Characterization of a recombinant bifunctional xylosidase/arabinofuranosidase from Phanerochaete chrysosporium. J Biosci Bioeng 2013; 116:152-9. [DOI: 10.1016/j.jbiosc.2013.02.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/31/2013] [Accepted: 02/03/2013] [Indexed: 11/20/2022]
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Jordan DB, Lee CC, Wagschal K, Braker JD. Activation of a GH43 β-xylosidase by divalent metal cations: slow binding of divalent metal and high substrate specificity. Arch Biochem Biophys 2013; 533:79-87. [PMID: 23500142 DOI: 10.1016/j.abb.2013.02.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 11/19/2022]
Abstract
RS223-BX of glycoside hydrolase family 43 is a β-d-xylosidase that is strongly activated (k(cat)/K(m) as much as 116-fold) by the addition of divalent metal cations, Ca(2+), Co(2+), Fe(2+), Mg(2+), Mn(2+) and Ni(2+). Slow activation by Mg(2+) was demonstrated (k(on) 0.013 s(-1) mM(-1), k(off) 0.008 s(-1)) at pH 7.0 and 25 °C. k(off) and k(on) values are independent of Mg(2+) concentration, but k(off) and k(on) are slower in the presence of increasing levels of substrate 4-nitrophenyl-β-D-xylopyranoside. The kinetics strongly suggest that M(2+) binds to the enzyme rapidly, forming E M(2+), followed by slow isomerization to the activated enzyme, E* M(2+). Moderately high values of kcat (7-30 s(-1)) were found for M(2+)-activated RS223-BX acting on xylobiose (natural substrate) at pH 7.0 and 25 °C. Certain M(2+)-activated RS223-BX exhibit the highest reported values of k(cat)/K(m) of any β-xylosidase acting on natural substrates: for example, at pH 7.0 and 25°C, xylobiose (Mn(2+), 190 s(-1) mM(-1)), xylotriose (Ca(2+), 150 s(-1) mM(-1)) and xylotetraose (Ca(2+), 260 s(-1) mM(-1)). There is potential for the enzyme to add value to industrial saccharification operations at low substrate and high d-glucose and high d-xylose concentrations.
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Affiliation(s)
- Douglas B Jordan
- USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604, USA.
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Divalent metal activation of a GH43 β-xylosidase. Enzyme Microb Technol 2012; 52:84-90. [PMID: 23273276 DOI: 10.1016/j.enzmictec.2012.10.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 10/06/2012] [Accepted: 10/26/2012] [Indexed: 11/21/2022]
Abstract
Depolymerization of xylan, a major fraction of lignocellulosic biomass, releases xylose which can be converted into transportation fuels and chemical feedstocks. A requisite enzyme for the breakdown of xylan is β-xylosidase. A gene encoding the 324-amino acid β-xylosidase, RS223-BX, was cloned from an anaerobic mixed microbial culture. This glycoside hydrolase belongs to family 43. Unlike other GH43 enzymes, RS223-BX can be strongly activated by exogenously supplied Ca(2+), Co(2+), Fe(2+), Mg(2+), Mn(2+) and Ni(2+) (e.g., 28-fold by Mg(2+)) and it is inhibited by Cu(2+) or Zn(2+). Sedimentation equilibrium centrifugation experiments indicated that the divalent metal cations mediate multimerization of the enzyme from a dimeric to a tetrameric state, which have equal catalytic activity on an active-site basis. Compared to the determined active sites of other GH43 β-xylosidases, the predicted active site of RS223-BX contains two additional amino acids with carboxylated side chains that provide potential sites for divalent metal cations to reside. Thus, the divalent metal cations likely occupy the active site and participate in the catalytic mechanism. RS223-BX accepts as substrate xylobiose, arabinobiose, 4-nitrophenyl-β-D-xylopyranoside, and 4-nitrophenyl-α-L-arabinofuranoside. Additionally, the enzyme has good pH and temperature stabilities and a large K(i) for D-glucose (1.3 M), favorable properties for performance in saccharification reactors.
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Rizk M, Antranikian G, Elleuche S. End-to-end gene fusions and their impact on the production of multifunctional biomass degrading enzymes. Biochem Biophys Res Commun 2012; 428:1-5. [DOI: 10.1016/j.bbrc.2012.09.142] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 09/30/2012] [Indexed: 11/29/2022]
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Highly active β-xylosidases of glycoside hydrolase family 43 operating on natural and artificial substrates. Appl Microbiol Biotechnol 2012; 97:4415-28. [PMID: 23053115 DOI: 10.1007/s00253-012-4475-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 09/24/2012] [Accepted: 09/25/2012] [Indexed: 10/27/2022]
Abstract
The hemicellulose xylan constitutes a major portion of plant biomass, a renewable feedstock available for conversion to biofuels and other bioproducts. β-xylosidase operates in the deconstruction of the polysaccharide to fermentable sugars. Glycoside hydrolase family 43 is recognized as a source of highly active β-xylosidases, some of which could have practical applications. The biochemical details of four GH43 β-xylosidases (those from Alkaliphilus metalliredigens QYMF, Bacillus pumilus, Bacillus subtilis subsp. subtilis str. 168, and Lactobacillus brevis ATCC 367) are examined here. Sedimentation equilibrium experiments indicate that the quaternary states of three of the enzymes are mixtures of monomers and homodimers (B. pumilus) or mixtures of homodimers and homotetramers (B. subtilis and L. brevis). k cat and k cat/K m values of the four enzymes are higher for xylobiose than for xylotriose, suggesting that the enzyme active sites comprise two subsites, as has been demonstrated by the X-ray structures of other GH43 β-xylosidases. The K i values for D-glucose (83.3-357 mM) and D-xylose (15.6-70.0 mM) of the four enzymes are moderately high. The four enzymes display good temperature (K t (0.5) ∼ 45 °C) and pH stabilities (>4.6 to <10.3). At pH 6.0 and 25 °C, the enzyme from L. brevis ATCC 367 displays the highest reported k cat and k cat/K m on natural substrates xylobiose (407 s(-1), 138 s(-1) mM(-1)), xylotriose (235 s(-1), 80.8 s(-1) mM(-1)), and xylotetraose (146 s(-1), 32.6 s(-1) mM(-1)).
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Dougherty MJ, D'haeseleer P, Hazen TC, Simmons BA, Adams PD, Hadi MZ. Glycoside hydrolases from a targeted compost metagenome, activity-screening and functional characterization. BMC Biotechnol 2012; 12:38. [PMID: 22759983 PMCID: PMC3477009 DOI: 10.1186/1472-6750-12-38] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 07/03/2012] [Indexed: 11/29/2022] Open
Abstract
Background Metagenomics approaches provide access to environmental genetic diversity for biotechnology applications, enabling the discovery of new enzymes and pathways for numerous catalytic processes. Discovery of new glycoside hydrolases with improved biocatalytic properties for the efficient conversion of lignocellulosic material to biofuels is a critical challenge in the development of economically viable routes from biomass to fuels and chemicals. Results Twenty-two putative ORFs (open reading frames) were identified from a switchgrass-adapted compost community based on sequence homology to related gene families. These ORFs were expressed in E. coli and assayed for predicted activities. Seven of the ORFs were demonstrated to encode active enzymes, encompassing five classes of hemicellulases. Four enzymes were over expressed in vivo, purified to homogeneity and subjected to detailed biochemical characterization. Their pH optima ranged between 5.5 - 7.5 and they exhibit moderate thermostability up to ~60-70°C. Conclusions Seven active enzymes were identified from this set of ORFs comprising five different hemicellulose activities. These enzymes have been shown to have useful properties, such as moderate thermal stability and broad pH optima, and may serve as the starting points for future protein engineering towards the goal of developing efficient enzyme cocktails for biomass degradation under diverse process conditions.
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Designer Xylanosomes: Protein Nanostructures for Enhanced Xylan Hydrolysis. Appl Biochem Biotechnol 2012; 167:395-411. [DOI: 10.1007/s12010-012-9680-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 04/10/2012] [Indexed: 10/28/2022]
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Wagschal K, Lee CC. Microplate-based active/inactive 1° screen for biomass degrading enzyme library purification and gene discovery. J Microbiol Methods 2012; 89:83-5. [DOI: 10.1016/j.mimet.2012.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 01/11/2012] [Accepted: 01/12/2012] [Indexed: 11/16/2022]
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Van Dyk JS, Pletschke BI. A review of lignocellulose bioconversion using enzymatic hydrolysis and synergistic cooperation between enzymes--factors affecting enzymes, conversion and synergy. Biotechnol Adv 2012; 30:1458-80. [PMID: 22445788 DOI: 10.1016/j.biotechadv.2012.03.002] [Citation(s) in RCA: 477] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 02/10/2012] [Accepted: 03/06/2012] [Indexed: 02/04/2023]
Abstract
Lignocellulose is a complex substrate which requires a variety of enzymes, acting in synergy, for its complete hydrolysis. These synergistic interactions between different enzymes have been investigated in order to design optimal combinations and ratios of enzymes for different lignocellulosic substrates that have been subjected to different pretreatments. This review examines the enzymes required to degrade various components of lignocellulose and the impact of pretreatments on the lignocellulose components and the enzymes required for degradation. Many factors affect the enzymes and the optimisation of the hydrolysis process, such as enzyme ratios, substrate loadings, enzyme loadings, inhibitors, adsorption and surfactants. Consideration is also given to the calculation of degrees of synergy and yield. A model is further proposed for the optimisation of enzyme combinations based on a selection of individual or commercial enzyme mixtures. The main area for further study is the effect of and interaction between different hemicellulases on complex substrates.
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Affiliation(s)
- J S Van Dyk
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa
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Abstract
Conversion of plant cell walls to ethanol constitutes second generation bioethanol production. The process consists of several steps: biomass selection/genetic modification, physiochemical pretreatment, enzymatic saccharification, fermentation and separation. Ultimately, it is desirable to combine as many of the biochemical steps as possible in a single organism to achieve CBP (consolidated bioprocessing). A commercially ready CBP organism is currently unreported. Production of second generation bioethanol is hindered by economics, particularly in the cost of pretreatment (including waste management and solvent recovery), the cost of saccharification enzymes (particularly exocellulases and endocellulases displaying kcat ~1 s−1 on crystalline cellulose), and the inefficiency of co-fermentation of 5- and 6-carbon monosaccharides (owing in part to redox cofactor imbalances in Saccharomyces cerevisiae).
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Biochemical and kinetic characterization of GH43 β-d-xylosidase/α-l-arabinofuranosidase and GH30 α-l-arabinofuranosidase/β-d-xylosidase from rumen metagenome. ACTA ACUST UNITED AC 2012; 39:143-52. [DOI: 10.1007/s10295-011-1009-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 06/15/2011] [Indexed: 10/18/2022]
Abstract
Abstract
The present study focuses on characterization of two hemicellulases, RuXyn1 and RuXyn2, from rumen bacterial metagenome and their capabilities for degradation of xylans. Glycosyl hydrolase (GH) family 43 β-d-xylosidase/α-l-arabinofuranosidase RuXyn1 can hydrolyze p-nitrophenyl-β-d-xylopyranoside (pNPX), p-nitrophenyl-α-l-arabinofuranoside (pNPA), and xylo-oligosaccharide substrates, while GH30 1,5-α-l-arabinofuranosidase/β-d-xylosidase RuXyn2, the first α-l-arabinofuranosidase assigned to this GH family, shows activities towards 1,5-α-l-arabinobiose and pNPX substrates but no activity for pNPA. Kinetic analysis for aryl-glycosides revealed that RuXyn2 had higher catalytic efficiency than RuXyn1 toward pNPX substrate. RuXyn1 shows high synergism with endoxylanase, elevating by 73% the reducing sugars released from brichwood xylans, and converted most intermediate xylo-oligosaccharide hydrolysate into xylose. The high xylose conversion capability of RuXyn1 suggests it has potential applications in enzymatic production of xylose and improvement of hemicellulose saccharification for production of biofuels. RuXyn2 shows no obviously synergistic effect in the endoxylanase-coupled assay for enzymatic saccharification of xylan. Further cosmid DNA sequencing revealed a neighboring putative GH43 α-l-arabinofuranosidase RuAra1 and two putative GH3 β-xylosidase/arabinosidases, RuXyn3 and RuXyn5, downstream of RuXyn2, indicating that this hemicellulase gene cluster may be responsible for production of end-product, xylose and arabinose, from hemicellulose biomass.
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Bao L, Huang Q, Chang L, Sun Q, Zhou J, Lu H. Cloning and Characterization of Two β-Glucosidase/Xylosidase Enzymes from Yak Rumen Metagenome. Appl Biochem Biotechnol 2011; 166:72-86. [PMID: 22020745 DOI: 10.1007/s12010-011-9405-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 10/04/2011] [Indexed: 10/16/2022]
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Catalytic properties of Talaromyces thermophilus α-l-arabinofuranosidase and its synergistic action with immobilized endo-β-1,4-xylanase. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.molcatb.2010.11.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Yoshida S, Hespen CW, Beverly RL, Mackie RI, Cann IKO. Domain analysis of a modular alpha-L-Arabinofuranosidase with a unique carbohydrate binding strategy from the fiber-degrading bacterium Fibrobacter succinogenes S85. J Bacteriol 2010; 192:5424-36. [PMID: 20709893 PMCID: PMC2950500 DOI: 10.1128/jb.00503-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Accepted: 08/03/2010] [Indexed: 11/20/2022] Open
Abstract
Family 43 glycoside hydrolases (GH43s) are known to exhibit various activities involved in hemicellulose hydrolysis. Thus, these enzymes contribute to efficient plant cell wall degradation, a topic of much interest for biofuel production. In this study, we characterized a unique GH43 protein from Fibrobacter succinogenes S85. The recombinant protein showed α-l-arabinofuranosidase activity, specifically with arabinoxylan. The enzyme is, therefore, an arabinoxylan arabinofuranohydrolase (AXH). The F. succinogenes AXH (FSUAXH1) is a modular protein that is composed of a signal peptide, a GH43 catalytic module, a unique β-sandwich module (XX domain), a family 6 carbohydrate-binding module (CBM6), and F. succinogenes-specific paralogous module 1 (FPm-1). Truncational analysis and site-directed mutagenesis of the protein revealed that the GH43 domain/XX domain constitute a new form of carbohydrate-binding module and that residue Y484 in the XX domain is essential for binding to arabinoxylan, although protein structural analyses may be required to confirm some of the observations. Kinetic studies demonstrated that the Y484A mutation leads to a higher k(cat) for a truncated derivative of FSUAXH1 composed of only the GH43 catalytic module and the XX domain. However, an increase in the K(m) for arabinoxylan led to a 3-fold decrease in catalytic efficiency. Based on the knowledge that most XX domains are found only in GH43 proteins, the evolutionary relationships within the GH43 family were investigated. These analyses showed that in GH43 members with a XX domain, the two modules have coevolved and that the length of a loop within the XX domain may serve as an important determinant of substrate specificity.
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Affiliation(s)
- Shosuke Yoshida
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
| | - Charles W. Hespen
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
| | - Robert L. Beverly
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
| | - Roderick I. Mackie
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
| | - Isaac K. O. Cann
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
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Jordan DB, Wagschal K. Properties and applications of microbial β-D-xylosidases featuring the catalytically efficient enzyme from Selenomonas ruminantium. Appl Microbiol Biotechnol 2010; 86:1647-58. [DOI: 10.1007/s00253-010-2538-y] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 03/02/2010] [Accepted: 03/03/2010] [Indexed: 11/28/2022]
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Dodd D, Cann IKO. Enzymatic deconstruction of xylan for biofuel production. GLOBAL CHANGE BIOLOGY. BIOENERGY 2009; 1:2-17. [PMID: 20431716 PMCID: PMC2860967 DOI: 10.1111/j.1757-1707.2009.01004.x] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The combustion of fossil-derived fuels has a significant impact on atmospheric carbon dioxide (CO(2)) levels and correspondingly is an important contributor to anthropogenic global climate change. Plants have evolved photosynthetic mechanisms in which solar energy is used to fix CO(2) into carbohydrates. Thus, combustion of biofuels, derived from plant biomass, can be considered a potentially carbon neutral process. One of the major limitations for efficient conversion of plant biomass to biofuels is the recalcitrant nature of the plant cell wall, which is composed mostly of lignocellulosic materials (lignin, cellulose, and hemicellulose). The heteropolymer xylan represents the most abundant hemicellulosic polysaccharide and is composed primarily of xylose, arabinose, and glucuronic acid. Microbes have evolved a plethora of enzymatic strategies for hydrolyzing xylan into its constituent sugars for subsequent fermentation to biofuels. Therefore, microorganisms are considered an important source of biocatalysts in the emerging biofuel industry. To produce an optimized enzymatic cocktail for xylan deconstruction, it will be valuable to gain insight at the molecular level of the chemical linkages and the mechanisms by which these enzymes recognize their substrates and catalyze their reactions. Recent advances in genomics, proteomics, and structural biology have revolutionized our understanding of the microbial xylanolytic enzymes. This review focuses on current understanding of the molecular basis for substrate specificity and catalysis by enzymes involved in xylan deconstruction.
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Affiliation(s)
- Dylan Dodd
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
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Engineering of a multifunctional hemicellulase. Biotechnol Lett 2009; 31:751-7. [DOI: 10.1007/s10529-009-9926-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 12/23/2008] [Accepted: 01/05/2009] [Indexed: 11/25/2022]
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Wagschal K, Heng C, Lee CC, Robertson GH, Orts WJ, Wong DWS. Purification and Characterization of a Glycoside Hydrolase Family 43 β-xylosidase from Geobacillus thermoleovorans IT-08. Appl Biochem Biotechnol 2008; 155:304-13. [DOI: 10.1007/s12010-008-8362-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 09/04/2008] [Indexed: 10/21/2022]
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