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Wardman JF, Withers SG. Carbohydrate-active enzyme (CAZyme) discovery and engineering via (Ultra)high-throughput screening. RSC Chem Biol 2024; 5:595-616. [PMID: 38966674 PMCID: PMC11221537 DOI: 10.1039/d4cb00024b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 05/16/2024] [Indexed: 07/06/2024] Open
Abstract
Carbohydrate-active enzymes (CAZymes) constitute a diverse set of enzymes that catalyze the assembly, degradation, and modification of carbohydrates. These enzymes have been fashioned into potent, selective catalysts by millennia of evolution, and yet are also highly adaptable and readily evolved in the laboratory. To identify and engineer CAZymes for different purposes, (ultra)high-throughput screening campaigns have been frequently utilized with great success. This review provides an overview of the different approaches taken in screening for CAZymes and how mechanistic understandings of CAZymes can enable new approaches to screening. Within, we also cover how cutting-edge techniques such as microfluidics, advances in computational approaches and synthetic biology, as well as novel assay designs are leading the field towards more informative and effective screening approaches.
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Affiliation(s)
- Jacob F Wardman
- Department of Biochemistry and Molecular Biology, University of British Columbia Vancouver BC V6T 1Z3 Canada
- Michael Smith Laboratories, University of British Columbia Vancouver BC V6T 1Z4 Canada
| | - Stephen G Withers
- Department of Biochemistry and Molecular Biology, University of British Columbia Vancouver BC V6T 1Z3 Canada
- Michael Smith Laboratories, University of British Columbia Vancouver BC V6T 1Z4 Canada
- Department of Chemistry, University of British Columbia Vancouver BC V6T 1Z1 Canada
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2
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Jain N, Tamura K, Déjean G, Van Petegem F, Brumer H. Orthogonal Active-Site Labels for Mixed-Linkage endo-β-Glucanases. ACS Chem Biol 2021; 16:1968-1984. [PMID: 33988963 DOI: 10.1021/acschembio.1c00063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Small molecule irreversible inhibitors are valuable tools for determining catalytically important active-site residues and revealing key details of the specificity, structure, and function of glycoside hydrolases (GHs). β-glucans that contain backbone β(1,3) linkages are widespread in nature, e.g., mixed-linkage β(1,3)/β(1,4)-glucans in the cell walls of higher plants and β(1,3)glucans in yeasts and algae. Commensurate with this ubiquity, a large diversity of mixed-linkage endoglucanases (MLGases, EC 3.2.1.73) and endo-β(1,3)-glucanases (laminarinases, EC 3.2.1.39 and EC 3.2.1.6) have evolved to specifically hydrolyze these polysaccharides, respectively, in environmental niches including the human gut. To facilitate biochemical and structural analysis of these GHs, with a focus on MLGases, we present here the facile chemo-enzymatic synthesis of a library of active-site-directed enzyme inhibitors based on mixed-linkage oligosaccharide scaffolds and N-bromoacetylglycosylamine or 2-fluoro-2-deoxyglycoside warheads. The effectiveness and irreversibility of these inhibitors were tested with exemplar MLGases and an endo-β(1,3)-glucanase. Notably, determination of inhibitor-bound crystal structures of a human-gut microbial MLGase from Glycoside Hydrolase Family 16 revealed the orthogonal labeling of the nucleophile and catalytic acid/base residues with homologous 2-fluoro-2-deoxyglycoside and N-bromoacetylglycosylamine inhibitors, respectively. We anticipate that the selectivity of these inhibitors will continue to enable the structural and mechanistic analyses of β-glucanases from diverse sources and protein families.
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Affiliation(s)
- Namrata Jain
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Kazune Tamura
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
| | - Guillaume Déjean
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
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Méndez-Líter JA, Nieto-Domínguez M, Fernández de Toro B, González Santana A, Prieto A, Asensio JL, Cañada FJ, de Eugenio LI, Martínez MJ. A glucotolerant β-glucosidase from the fungus Talaromyces amestolkiae and its conversion into a glycosynthase for glycosylation of phenolic compounds. Microb Cell Fact 2020; 19:127. [PMID: 32522206 PMCID: PMC7288487 DOI: 10.1186/s12934-020-01386-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 06/04/2020] [Indexed: 12/23/2022] Open
Abstract
Background The interest for finding novel β-glucosidases that can improve the yields to produce second-generation (2G) biofuels is still very high. One of the most desired features for these enzymes is glucose tolerance, which enables their optimal activity under high-glucose concentrations. Besides, there is an additional focus of attention on finding novel enzymatic alternatives for glycoside synthesis, for which a mutated version of glycosidases, named glycosynthases, has gained much interest in recent years. Results In this work, a glucotolerant β-glucosidase (BGL-1) from the ascomycete fungus Talaromyces amestolkiae has been heterologously expressed in Pichia pastoris, purified, and characterized. The enzyme showed good efficiency on p-nitrophenyl glucopyranoside (pNPG) (Km= 3.36 ± 0.7 mM, kcat= 898.31 s−1), but its activity on cellooligosaccharides, the natural substrates of these enzymes, was much lower, which could limit its exploitation in lignocellulose degradation applications. Interestingly, when examining the substrate specificity of BGL-1, it showed to be more active on sophorose, the β-1,2 disaccharide of glucose, than on cellobiose. Besides, the transglycosylation profile of BGL-1 was examined, and, for expanding its synthetic capacities, it was converted into a glycosynthase. The mutant enzyme, named BGL-1-E521G, was able to use α-d-glucosyl-fluoride as donor in glycosylation reactions, and synthesized glucosylated derivatives of different pNP-sugars in a regioselective manner, as well as of some phenolic compounds of industrial interest, such as epigallocatechin gallate (EGCG). Conclusions In this work, we report the characterization of a novel glucotolerant 1,2-β-glucosidase, which also has a considerable activity on 1,4-β-glucosyl bonds, that has been cloned in P. pastoris, produced, purified and characterized. In addition, the enzyme was converted into an efficient glycosynthase, able to transfer glucose molecules to a diversity of acceptors for obtaining compounds of interest. The remarkable capacities of BGL-1 and its glycosynthase mutant, both in hydrolysis and synthesis, suggest that it could be an interesting tool for biotechnological applications.
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Affiliation(s)
- Juan Antonio Méndez-Líter
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Manuel Nieto-Domínguez
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Beatriz Fernández de Toro
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Andrés González Santana
- Glycochemistry and Molecular Recognition Group, Instituto de Química Orgánica General (IQOG-CSIC), Calle Juan de la Cierva, 3, 28006, Madrid, Spain
| | - Alicia Prieto
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Juan Luis Asensio
- Glycochemistry and Molecular Recognition Group, Instituto de Química Orgánica General (IQOG-CSIC), Calle Juan de la Cierva, 3, 28006, Madrid, Spain
| | - Francisco Javier Cañada
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Laura Isabel de Eugenio
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - María Jesús Martínez
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
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Méndez-Líter JA, Tundidor I, Nieto-Domínguez M, de Toro BF, González Santana A, de Eugenio LI, Prieto A, Asensio JL, Cañada FJ, Sánchez C, Martínez MJ. Transglycosylation products generated by Talaromyces amestolkiae GH3 β-glucosidases: effect of hydroxytyrosol, vanillin and its glucosides on breast cancer cells. Microb Cell Fact 2019; 18:97. [PMID: 31151435 PMCID: PMC6544938 DOI: 10.1186/s12934-019-1147-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 05/22/2019] [Indexed: 12/18/2022] Open
Abstract
Background Transglycosylation represents one of the most promising approaches for obtaining novel glycosides, and plant phenols and polyphenols are emerging as one of the best targets for creating new molecules with enhanced capacities. These compounds can be found in diet and exhibit a wide range of bioactivities, such as antioxidant, antihypertensive, antitumor, neuroprotective and anti-inflammatory, and the eco-friendly synthesis of glycosides from these molecules can be a suitable alternative for increasing their health benefits. Results Transglycosylation experiments were carried out using different GH3 β-glucosidases from the fungus Talaromyces amestolkiae. After a first screening with a wide variety of potential transglycosylation acceptors, mono-glucosylated derivatives of hydroxytyrosol, vanillin alcohol, 4-hydroxybenzyl alcohol, and hydroquinone were detected. The reaction products were analyzed by thin-layer chromatography, high-pressure liquid chromatography, and mass spectrometry. Hydroxytyrosol and vanillyl alcohol were selected as the best options for transglycosylation optimization, with a final conversion yield of 13.8 and 19% of hydroxytyrosol and vanillin glucosides, respectively. NMR analysis confirmed the structures of these compounds. The evaluation of the biological effect of these glucosides using models of breast cancer cells, showed an enhancement in the anti-proliferative capacity of the vanillin derivative, and an improved safety profile of both glucosides. Conclusions GH3 β-glucosidases from T. amestolkiae expressed in P. pastoris were able to transglycosylate a wide variety of acceptors. Between them, phenolic molecules like hydroxytyrosol, vanillin alcohol, 4-hydroxybenzyl alcohol, and hydroquinone were the most suitable for its interesting biological properties. The glycosides of hydroxytyrosol and vanillin were tested, and they improved the biological activities of the original aglycons on breast cancer cells. Electronic supplementary material The online version of this article (10.1186/s12934-019-1147-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Juan Antonio Méndez-Líter
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Isabel Tundidor
- Department of Biochemistry and Molecular Biology, Complutense University, Madrid, Spain.,Instituto de Investigación Hospital 12 de Octubre, Madrid, Spain
| | - Manuel Nieto-Domínguez
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Beatriz Fernández de Toro
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Andrés González Santana
- Glycochemistry and Molecular Recognition Group, Instituto de Química Orgánica General (IQOG-CSIC), Calle Juan de la Cierva, 3, 28006, Madrid, Spain
| | - Laura Isabel de Eugenio
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Alicia Prieto
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Juan Luis Asensio
- Glycochemistry and Molecular Recognition Group, Instituto de Química Orgánica General (IQOG-CSIC), Calle Juan de la Cierva, 3, 28006, Madrid, Spain
| | - Francisco Javier Cañada
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Cristina Sánchez
- Department of Biochemistry and Molecular Biology, Complutense University, Madrid, Spain.,Instituto de Investigación Hospital 12 de Octubre, Madrid, Spain
| | - María Jesús Martínez
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
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Armstrong Z, Liu F, Chen HM, Hallam SJ, Withers SG. Systematic Screening of Synthetic Gene-Encoded Enzymes for Synthesis of Modified Glycosides. ACS Catal 2019. [DOI: 10.1021/acscatal.8b05179] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Zachary Armstrong
- Genome Science and Technology Program, University of British Columbia, 2329 West Mall, Vancouver, British Columbia, Canada V6T 1Z4
| | - Feng Liu
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Hong-Ming Chen
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Steven J. Hallam
- Genome Science and Technology Program, University of British Columbia, 2329 West Mall, Vancouver, British Columbia, Canada V6T 1Z4
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
- Graduate Program in Bioinformatics, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Stephen G. Withers
- Genome Science and Technology Program, University of British Columbia, 2329 West Mall, Vancouver, British Columbia, Canada V6T 1Z4
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
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Aulitto M, Fusco S, Limauro D, Fiorentino G, Bartolucci S, Contursi P. Galactomannan degradation by thermophilic enzymes: a hot topic for biotechnological applications. World J Microbiol Biotechnol 2019; 35:32. [DOI: 10.1007/s11274-019-2591-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/10/2019] [Indexed: 01/06/2023]
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Ben Bdira F, Artola M, Overkleeft HS, Ubbink M, Aerts JMFG. Distinguishing the differences in β-glycosylceramidase folds, dynamics, and actions informs therapeutic uses. J Lipid Res 2018; 59:2262-2276. [PMID: 30279220 PMCID: PMC6277158 DOI: 10.1194/jlr.r086629] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/04/2018] [Indexed: 12/12/2022] Open
Abstract
Glycosyl hydrolases (GHs) are carbohydrate-active enzymes that hydrolyze a specific β-glycosidic bond in glycoconjugate substrates; β-glucosidases degrade glucosylceramide, a ubiquitous glycosphingolipid. GHs are grouped into structurally similar families that themselves can be grouped into clans. GH1, GH5, and GH30 glycosidases belong to clan A hydrolases with a catalytic (β/α)8 TIM barrel domain, whereas GH116 belongs to clan O with a catalytic (α/α)6 domain. In humans, GH abnormalities underlie metabolic diseases. The lysosomal enzyme glucocerebrosidase (family GH30), deficient in Gaucher disease and implicated in Parkinson disease etiology, and the cytosol-facing membrane-bound glucosylceramidase (family GH116) remove the terminal glucose from the ceramide lipid moiety. Here, we compare enzyme differences in fold, action, dynamics, and catalytic domain stabilization by binding site occupancy. We also explore other glycosidases with reported glycosylceramidase activity, including human cytosolic β-glucosidase, intestinal lactase-phlorizin hydrolase, and lysosomal galactosylceramidase. Last, we describe the successful translation of research to practice: recombinant glycosidases and glucosylceramide metabolism modulators are approved drug products (enzyme replacement therapies). Activity-based probes now facilitate the diagnosis of enzyme deficiency and screening for compounds that interact with the catalytic pocket of glycosidases. Future research may deepen the understanding of the functional variety of these enzymes and their therapeutic potential.
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Affiliation(s)
- Fredj Ben Bdira
- Departments of Macromolecular Biochemistry,Leiden Institute of Chemistry, Leiden, The Netherlands
| | - Marta Artola
- Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden, The Netherlands
| | - Herman S Overkleeft
- Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden, The Netherlands
| | - Marcellus Ubbink
- Departments of Macromolecular Biochemistry,Leiden Institute of Chemistry, Leiden, The Netherlands
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8
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Kwan DH. Structure-Guided Directed Evolution of Glycosidases: A Case Study in Engineering a Blood Group Antigen-Cleaving Enzyme. Methods Enzymol 2018; 597:25-53. [PMID: 28935105 DOI: 10.1016/bs.mie.2017.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Directed evolution is an incredibly powerful strategy for engineering enzyme function. Applying this approach to glycosidases offers enormous potential for the development of highly specialized tools in chemical glycobiology. Performing enzyme directed evolution requires the generation, by random mutagenesis, of mutant libraries from which large numbers of variant enzymes must be screened in high-throughput assays. A structure-guided "semirational" method for library creation allows researchers to target specific amino acid positions for mutagenesis, concentrating mutations where they might be most effective in order to produce mutant libraries of a manageable size, minimizing screening effort while maximizing the chances of finding improved mutants. Well-designed assays, which may use specially prepared substrates, enable efficient screening of these mutant libraries. This chapter will detail general methods in the structure-guided directed evolution of glycosidases, which have previously been employed in engineering a blood group antigen-cleaving enzyme.
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Affiliation(s)
- David H Kwan
- Centre for Applied Synthetic Biology, Centre for Structural and Functional Genomics, Concordia University, Montréal, Québec, Canada.
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9
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Pote AR, Vannam R, Richard A, Gascón J, Peczuh MW. Formation of and Glycosylation with Per‐
O
‐Acetyl Septanosyl Halides: Rationalizing Complex Reactivity En Route to
p
‐Nitrophenyl Septanosides. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Aditya R. Pote
- Department of Chemistry University of Connecticut 55 N. Eagleville Road, U3060 06269‐3060 Storrs CT USA
| | - Raghu Vannam
- Department of Chemistry University of Connecticut 55 N. Eagleville Road, U3060 06269‐3060 Storrs CT USA
| | - Alissa Richard
- Department of Chemistry University of Connecticut 55 N. Eagleville Road, U3060 06269‐3060 Storrs CT USA
| | - José Gascón
- Department of Chemistry University of Connecticut 55 N. Eagleville Road, U3060 06269‐3060 Storrs CT USA
| | - Mark W. Peczuh
- Department of Chemistry University of Connecticut 55 N. Eagleville Road, U3060 06269‐3060 Storrs CT USA
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Jain N, Attia MA, Offen WA, Davies GJ, Brumer H. Synthesis and application of a highly branched, mechanism-based 2-deoxy-2-fluoro-oligosaccharide inhibitor of endo-xyloglucanases. Org Biomol Chem 2018; 16:8732-8741. [DOI: 10.1039/c8ob02250j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Xyloglucan (XyG) is a complex polysaccharide that is ubiquitous and often abundant in the cell walls of terrestrial plants.
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Affiliation(s)
- Namrata Jain
- Michael Smith Laboratories
- University of British Columbia
- Vancouver
- Canada
- Department of Chemistry
| | - Mohamed A. Attia
- Michael Smith Laboratories
- University of British Columbia
- Vancouver
- Canada
- Department of Chemistry
| | | | | | - Harry Brumer
- Michael Smith Laboratories
- University of British Columbia
- Vancouver
- Canada
- Department of Chemistry
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11
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Nieto-Domínguez M, Prieto A, Fernández de Toro B, Cañada FJ, Barriuso J, Armstrong Z, Withers SG, de Eugenio LI, Martínez MJ. Enzymatic fine-tuning for 2-(6-hydroxynaphthyl) β-D-xylopyranoside synthesis catalyzed by the recombinant β-xylosidase BxTW1 from Talaromyces amestolkiae. Microb Cell Fact 2016; 15:171. [PMID: 27716291 PMCID: PMC5050587 DOI: 10.1186/s12934-016-0568-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/23/2016] [Indexed: 02/02/2023] Open
Abstract
Background Glycosides are compounds displaying crucial biological roles and plenty of applications. Traditionally, these molecules have been chemically obtained, but its efficient production is limited by the lack of regio- and stereo-selectivity of the chemical synthesis. As an interesting alternative, glycosidases are able to catalyze the formation of glycosides in a process considered green and highly selective. In this study, we report the expression and characterization of a fungal β-xylosidase in Pichia pastoris. The transglycosylation potential of the enzyme was evaluated and its applicability in the synthesis of a selective anti-proliferative compound demonstrated. Results The β-xylosidase BxTW1 from the ascomycete fungus Talaromyces amestolkiae was cloned and expressed in Pichia pastoris GS115. The yeast secreted 8 U/mL of β-xylosidase that was purified by a single step of cation-exchange chromatography. rBxTW1 in its active form is an N-glycosylated dimer of about 200 kDa. The enzyme was biochemically characterized displaying a Km and kcat against p-nitrophenyl-β-d-xylopyranoside of 0.20 mM and 69.3 s−1 respectively, and its maximal activity was achieved at pH 3 and 60 °C. The glycan component of rBxTW1 was also analyzed in order to interpret the observed loss of stability and maximum velocity when compared with the native enzyme. A rapid screening of aglycone specificity was performed, revealing a remarkable high number of potential transxylosylation acceptors for rBxTW1. Based on this analysis, the enzyme was successfully tested in the synthesis of 2-(6-hydroxynaphthyl) β-d-xylopyranoside, a well-known selective anti-proliferative compound, enzymatically obtained for the first time. The application of response surface methodology, following a Box-Behnken design, enhanced this production by eightfold, fitting the reaction conditions into a multiparametric model. The naphthyl derivative was purified and its identity confirmed by NMR. Conclusions A β-xylosidase from T. amestolkiae was produced in P. pastoris and purified. The final yields were much higher than those attained for the native protein, although some loss of stability and maximum velocity was observed. rBxTW1 displayed remarkable acceptor versatility in transxylosylation, catalyzing the synthesis of a selective antiproliferative compound, 2-(6-hydroxynaphthyl) β-d-xylopyranoside. These results evidence the interest of rBxTW1 for transxylosylation of relevant products with biotechnological interest. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0568-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Manuel Nieto-Domínguez
- Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Alicia Prieto
- Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Beatriz Fernández de Toro
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Francisco Javier Cañada
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Jorge Barriuso
- Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Zach Armstrong
- Department of Chemistry, Centre for High-Throughput Biology, University of British Columbia, Vancouver, Canada
| | - Stephen G Withers
- Department of Chemistry, Centre for High-Throughput Biology, University of British Columbia, Vancouver, Canada
| | - Laura I de Eugenio
- Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
| | - María Jesús Martínez
- Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
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12
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Affiliation(s)
- Prakram Singh Chauhan
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, SAS Nagar, Mohali, India and
| | - Naveen Gupta
- Department of Microbiology, Panjab University, Chandigarh, India
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13
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Li YX, Liu Y, Yan QJ, Yang SQ, Jiang ZQ. Characterization of a novel glycoside hydrolase family 5 β-mannosidase from Absidia corymbifera with high transglycosylation activity. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2015.09.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Li C, Kim YW. Characterization of a Galactosynthase Derived fromBacillus circulansβ-Galactosidase: Facile Synthesis ofD-Lacto- andD-Galacto-N-bioside. Chembiochem 2014; 15:522-6. [DOI: 10.1002/cbic.201300699] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Indexed: 11/10/2022]
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15
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Saburi W, Kobayashi M, Mori H, Okuyama M, Kimura A. Replacement of the catalytic nucleophile aspartyl residue of dextran glucosidase by cysteine sulfinate enhances transglycosylation activity. J Biol Chem 2013; 288:31670-7. [PMID: 24052257 DOI: 10.1074/jbc.m113.491449] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dextran glucosidase from Streptococcus mutans (SmDG) catalyzes the hydrolysis of an α-1,6-glucosidic linkage at the nonreducing end of isomaltooligosaccharides and dextran. This enzyme has an Asp-194 catalytic nucleophile and two catalytically unrelated Cys residues, Cys-129 and Cys-532. Cys-free SmDG was constructed by replacement with Ser (C129S/C532S (2CS), the activity of which was the same as that of the wild type, SmDG). The nucleophile mutant of 2CS was generated by substitution of Asp-194 with Cys (D194C-2CS). The hydrolytic activity of D194C-2CS was 8.1 × 10(-4) % of 2CS. KI-associated oxidation of D194C-2CS increased the activity up to 0.27% of 2CS, which was 330 times higher than D194C-2CS. Peptide-mapping mass analysis of the oxidized D194C-2CS (Ox-D194C-2CS) revealed that Cys-194 was converted into cysteine sulfinate. Ox-D194C-2CS and 2CS shared the same properties (optimum pH, pI, and substrate specificity), whereas Ox-D194C-2CS had much higher transglucosylation activity than 2CS. This is the first study indicating that a more acidic nucleophile (-SOO(-)) enhances transglycosylation. The introduction of cysteine sulfinate as a catalytic nucleophile could be a novel approach to enhance transglycosylation.
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Affiliation(s)
- Wataru Saburi
- From the Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8689, Japan
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16
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Single amino acid substitutions in HXT2.4 from Scheffersomyces stipitis lead to improved cellobiose fermentation by engineered Saccharomyces cerevisiae. Appl Environ Microbiol 2012; 79:1500-7. [PMID: 23263959 DOI: 10.1128/aem.03253-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Saccharomyces cerevisiae cannot utilize cellobiose, but this yeast can be engineered to ferment cellobiose by introducing both cellodextrin transporter (cdt-1) and intracellular β-glucosidase (gh1-1) genes from Neurospora crassa. Here, we report that an engineered S. cerevisiae strain expressing the putative hexose transporter gene HXT2.4 from Scheffersomyces stipitis and gh1-1 can also ferment cellobiose. This result suggests that HXT2.4p may function as a cellobiose transporter when HXT2.4 is overexpressed in S. cerevisiae. However, cellobiose fermentation by the engineered strain expressing HXT2.4 and gh1-1 was much slower and less efficient than that by an engineered strain that initially expressed cdt-1 and gh1-1. The rate of cellobiose fermentation by the HXT2.4-expressing strain increased drastically after serial subcultures on cellobiose. Sequencing and retransformation of the isolated plasmids from a single colony of the fast cellobiose-fermenting culture led to the identification of a mutation (A291D) in HXT2.4 that is responsible for improved cellobiose fermentation by the evolved S. cerevisiae strain. Substitutions for alanine (A291) of negatively charged amino acids (A291E and A291D) or positively charged amino acids (A291K and A291R) significantly improved cellobiose fermentation. The mutant HXT2.4(A291D) exhibited 1.5-fold higher K(m) and 4-fold higher V(max) values than those from wild-type HXT2.4, whereas the expression levels were the same. These results suggest that the kinetic properties of wild-type HXT2.4 expressed in S. cerevisiae are suboptimal, and mutations of A291 into bulky charged amino acids might transform HXT2.4p into an efficient transporter, enabling rapid cellobiose fermentation by engineered S. cerevisiae strains.
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17
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Minig M, Mazzaferro LS, Erra-Balsells R, Petroselli G, Breccia JD. α-Rhamnosyl-β-glucosidase-catalyzed reactions for analysis and biotransformations of plant-based foods. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:11238-11243. [PMID: 21834586 DOI: 10.1021/jf202412e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Most aroma compounds exist in vegetal tissues as disaccharide conjugates, rutinose being an abundant sugar moiety in grapes. The availability of aroma precursors would facilitate analytical analysis of plant-based foods. The diglycosidase α-rhamnosyl-β-glucosidase from Acremonium sp. DSM 24697 efficiently transglycosylated the rutinose moiety from hesperidin to 2-phenylethanol, geraniol, and nerol in an aqueous-organic biphasic system. 2-Phenethyl rutinoside was synthesized up to millimolar level with an 80% conversion regarding the donor hesperidin. The hydrolysis of the synthesized aroma precursors was not detected in an aqueous medium. However, in the presence of ethanol as a sugar acceptor, the enzyme was able to transfer the disaccharide residue forming the alkyl-rutinoside. The aroma precursors were significantly hydrolyzed (up to 3-4% in 2 h at 30 °C), which indicated the potential use of the enzyme for biotechnological applications, for example, in aroma modulation of fermented foods.
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Affiliation(s)
- Marisol Minig
- INCITAP-Consejo Nacional de Investigaciones Científicas y Técnicas, Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, Av. Uruguay 151, (6300) Santa Rosa, La Pampa, Argentina
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18
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Mazzaferro LS, Breccia JD. Functional and biotechnological insights into diglycosidases*. BIOCATAL BIOTRANSFOR 2011. [DOI: 10.3109/10242422.2011.594882] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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19
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Kuntothom T, Raab M, Tvaroška I, Fort S, Pengthaisong S, Cañada J, Calle L, Jiménez-Barbero J, Ketudat Cairns JR, Hrmova M. Binding of β-d-Glucosides and β-d-Mannosides by Rice and Barley β-d-Glycosidases with Distinct Substrate Specificities. Biochemistry 2010; 49:8779-93. [DOI: 10.1021/bi101112c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Teerachai Kuntothom
- School of Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Michal Raab
- Department of Structure and Function of Saccharides, Institute of Chemistry, Center for Glycomics, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Igor Tvaroška
- Department of Structure and Function of Saccharides, Institute of Chemistry, Center for Glycomics, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Sebastien Fort
- Centre de Recherches sur les Macromolecules Vegetales, Grenoble, France
| | - Salila Pengthaisong
- School of Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Javier Cañada
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Luis Calle
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | | | - James R. Ketudat Cairns
- School of Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Maria Hrmova
- Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond, Australia
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20
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Zhang R, Li C, Williams LK, Rempel BP, Brayer GD, Withers SG. Directed "in situ" inhibitor elongation as a strategy to structurally characterize the covalent glycosyl-enzyme intermediate of human pancreatic alpha-amylase. Biochemistry 2009; 48:10752-64. [PMID: 19803533 DOI: 10.1021/bi901400p] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
While covalent catalytic intermediates of retaining alpha-transglycosylases have been structurally characterized previously, no such information for a hydrolytic alpha-amylase has been obtained. This study presents a new "in situ" enzymatic elongation methodology that, for the first time, has allowed the isolation and structural characterization of a catalytically competent covalent glycosyl-enzyme intermediate with human pancreatic alpha-amylase. This has been achieved by the use of a 5-fluoro-beta-l-idosyl fluoride "warhead" in conjunction with either alpha-maltotriosyl fluoride or 4'-O-methyl-alpha-maltosyl fluoride as elongation agents. This generates an oligosaccharyl-5-fluoroglycosyl fluoride that then reacts with the free enzyme. The resultant covalent intermediates are extremely stable, with hydrolytic half-lives on the order of 240 h for the trisaccharide complex. In the presence of maltose, however, they undergo turnover via transglycosylation according to a half-life of less than 1 h. Structural studies of intermediate complexes unambiguously show the covalent attachment of a 5-fluoro-alpha-l-idosyl moiety in the chair conformation to the side chain of the catalytic nucleophile D197. The elongated portions of the intermediate complexes are found to bind in the high-affinity -2 and -3 binding subsites, forming extensive hydrogen-bonding interactions. Comparative structural analyses with the related noncovalent complex formed by acarbose highlight the structural rigidity of the enzyme surface during catalysis and the key role that substrate conformational flexibility must play in this process. Taken together, the structural data provide atomic details of several key catalytic steps. The scope of this elongation approach to probe the active sites and catalytic mechanisms of alpha-amylases is further demonstrated through preliminary experiments with porcine pancreatic alpha-amylase.
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Affiliation(s)
- Ran Zhang
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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21
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Rakić B, Withers SG. Recent Developments in Glycoside Synthesis with Glycosynthases and Thioglycoligases. Aust J Chem 2009. [DOI: 10.1071/ch09059] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Glycosynthases are hydrolytically incompetent engineered glycosidases that catalyze the high-yielding synthesis of glycoconjugates from glycosyl fluoride donor substrates and appropriate acceptors. Glycosynthases from more than 10 glycoside hydrolase families have now been generated, allowing the synthesis of a wide range of oligosaccharides. Recent examples include glycosynthase-mediated syntheses of xylo-oligosaccharides, xyloglucans, glycolipids, and aryl glycosides. Glycosynthases have also now been generated from inverting glycosidases, increasing the range of enzyme scaffolds. Improvement of glycosynthase activity and broadening of specificity has been achieved through directed evolution approaches, and several novel high-throughput screens have been developed to allow this. Finally, metabolically stable glycoside analogues have been generated using another class of mutant glycosidases: thioglycoligases. Recent developments in all these aspects are discussed.
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22
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Abstract
Cellulolytic bacteria and fungi have been shown to use two different approaches to degrade cellulose. Most aerobic microbes secrete sets of individual cellulases, many of which contain a carbohydrate binding molecule (CBM), which act synergistically on native cellulose. Most anaerobic microorganisms produce large multienzyme complexes called cellulosomes, which are usually attached to the outer surface of the microorganism. Most of the cellulosomal enzymes lack a CBM, but the cohesin subunit, to which they are bound, does contain a CBM. The cellulases present in each class show considerable overlap in their catalytic domains, and processive cellulases (exocellulases and processive endocellulases) are the most abundant components of both the sets of free enzymes and of the cellulosomal cellulases. Analysis of the genomic sequences of two cellulolytic bacteria, Cytophaga hutchinsonii, an aerobe, and Fibrobacter succinogenes, an anaerobe, suggest that these organisms must use a third mechanism. This is because neither of these organisms, encodes processive cellulases and most of their many endocellulase genes do not encode CBMs. Furthermore, neither organism appears to encode the dockerin and cohesin domains that are key components of cellulosomes.
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Affiliation(s)
- David B Wilson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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23
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Rempel BP, Withers SG. Covalent inhibitors of glycosidases and their applications in biochemistry and biology. Glycobiology 2008; 18:570-86. [PMID: 18499865 DOI: 10.1093/glycob/cwn041] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Glycoside hydrolases are important enzymes in a number of essential biological processes. Irreversible inhibitors of this class of enzyme have attracted interest as probes of both structure and function. In this review we discuss some of the compounds used to covalently modify glycosidases, their use in residue identification, structural and mechanistic investigations, and finally their applications, both in vitro and in vivo, to complex biological systems.
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Affiliation(s)
- Brian P Rempel
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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24
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Wilkinson SM, Liew CW, Mackay JP, Salleh HM, Withers SG, McLeod MD. Escherichia coli Glucuronylsynthase: An Engineered Enzyme for the Synthesis of β-Glucuronides. Org Lett 2008; 10:1585-8. [DOI: 10.1021/ol8002767] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shane M. Wilkinson
- School of Chemistry, University of Sydney, NSW 2006, Australia, School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia, and Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Chu W. Liew
- School of Chemistry, University of Sydney, NSW 2006, Australia, School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia, and Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Joel P. Mackay
- School of Chemistry, University of Sydney, NSW 2006, Australia, School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia, and Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Hamzah M. Salleh
- School of Chemistry, University of Sydney, NSW 2006, Australia, School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia, and Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Stephen G. Withers
- School of Chemistry, University of Sydney, NSW 2006, Australia, School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia, and Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Malcolm D. McLeod
- School of Chemistry, University of Sydney, NSW 2006, Australia, School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia, and Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
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25
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Dechancie J, Clemente FR, Smith AJT, Gunaydin H, Zhao YL, Zhang X, Houk KN. How similar are enzyme active site geometries derived from quantum mechanical theozymes to crystal structures of enzyme-inhibitor complexes? Implications for enzyme design. Protein Sci 2007; 16:1851-66. [PMID: 17766382 PMCID: PMC2206971 DOI: 10.1110/ps.072963707] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Quantum mechanical optimizations of theoretical enzymes (theozymes), which are predicted catalytic arrays of biological functionalities stabilizing a transition state, have been carried out for a set of nine diverse enzyme active sites. For each enzyme, the theozyme for the rate-determining transition state plus the catalytic groups modeled by side-chain mimics was optimized using B3LYP/6-31G(d) or, in one case, HF/3-21G(d) quantum mechanical calculations. To determine if the theozyme can reproduce the natural evolutionary catalytic geometry, the positions of optimized catalytic atoms, i.e., covalent, partial covalent, or stabilizing interactions with transition state atoms, are compared to the positions of the atoms in the X-ray crystal structure with a bound inhibitor. These structure comparisons are contrasted to computed substrate-active site structures surrounded by the same theozyme residues. The theozyme/transition structure is shown to predict geometries of active sites with an average RMSD of 0.64 A from the crystal structure, while the RMSD for the bound intermediate complexes are significantly higher at 1.42 A. The implications for computational enzyme design are discussed.
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Affiliation(s)
- Jason Dechancie
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
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26
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Kim YW, Chen HM, Kim JH, Müllegger J, Mahuran D, Withers SG. Thioglycoligase-based assembly of thiodisaccharides: screening as beta-galactosidase inhibitors. Chembiochem 2007; 8:1495-9. [PMID: 17661304 PMCID: PMC2910745 DOI: 10.1002/cbic.200700263] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Young-Wan Kim
- Department of Chemistry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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27
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Gomes J, Terler K, Kratzer R, Kainz E, Steiner W. Production of thermostable β-mannosidase by a strain of Thermoascus aurantiacus: Isolation, partial purification and characterization of the enzyme. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2006.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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28
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Kim YW, Chen H, Kim JH, Withers SG. Catalytic properties of a mutant β-galactosidase fromXanthomonas manihotisengineered to synthesize galactosyl-thio-β-1,3 and -β-1,4-glycosides. FEBS Lett 2006; 580:4377-81. [PMID: 16844121 DOI: 10.1016/j.febslet.2006.06.095] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Revised: 06/30/2006] [Accepted: 06/30/2006] [Indexed: 11/24/2022]
Abstract
The identity of the acid/base catalyst of the Family 35 beta-galactosidases from Xanthomonas manihotis (BgaX) has been confirmed as Glu184 by kinetic analysis of mutants modified at that position. The Glu184Ala mutant of BgaX is shown to function as an efficient thioglycoligase, which synthesises thiogalactosides with linkages to the 3 and 4 positions of glucosides and galactosides in high (>80%) yields. Kinetic analysis of the thioglycoligase reveals glycosyl donor K(m) values of 1.5-21 microM and glycosyl acceptor K(m) values from 180 to 500 microM. This mutant should be a valuable catalyst for the synthesis of metabolically stable analogues of this important glycosidic linkage.
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Affiliation(s)
- Young-Wan Kim
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1
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29
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Hommalai G, Chaiyen P, Svasti J. Studies on the transglucosylation reactions of cassava and Thai rosewood β-glucosidases using 2-deoxy-2-fluoro-glycosyl-enzyme intermediates. Arch Biochem Biophys 2005; 442:11-20. [PMID: 16139237 DOI: 10.1016/j.abb.2005.07.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Revised: 07/25/2005] [Accepted: 07/27/2005] [Indexed: 10/25/2022]
Abstract
Beta-glucosidases from cassava and Thai rosewood can synthesize a variety of alkyl glucosides using various alcohols as glucosyl acceptors for transglucosylation. Both enzymes were inactivated by 2-deoxy-2-fluoro-sugar analogues to form the covalent glycosyl-enzyme intermediates, indicating that the reaction mechanism was of the double-replacement type. The trapped enzyme intermediates were used for investigating transglucosylation specificity, by measuring the rate of reactivation by various alcohols. The glucosyl-enzyme intermediate from the cassava enzyme showed a 20- to 120-fold higher rate of glucose transfer to alcohols than the glucosyl-enzyme intermediate from the Thai rosewood enzyme. Kinetic analysis indicated that the aglycone binding site of the cassava enzyme was hydrophobic, since the enzyme bound better to more hydrophobic alcohols and showed poor transfer of glucose to hydrophilic sugars. With butanol, transglucosylation was faster with the primary alcohols than with the secondary or tertiary alcohol. Studies with ethanol and chloro-substituted ethanols indicated that the rate of transglucosylation was significantly faster with alcohols with lower pKa values, where the reactive alkoxide was more readily generated, indicating that the formation of the alkoxide species was a major step governing the formation of the transition state in the cassava enzyme.
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Affiliation(s)
- Greanggrai Hommalai
- Department of Biochemistry, Center for Protein Structure and Function, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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30
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Perugino G, Cobucci-Ponzano B, Rossi M, Moracci M. Recent Advances in the Oligosaccharide Synthesis Promoted by Catalytically Engineered Glycosidases. Adv Synth Catal 2005. [DOI: 10.1002/adsc.200505070] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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31
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Ducros VMA, Tarling CA, Zechel DL, Brzozowski AM, Frandsen TP, von Ossowski I, Schülein M, Withers SG, Davies GJ. Anatomy of glycosynthesis: structure and kinetics of the Humicola insolens Cel7B E197A and E197S glycosynthase mutants. CHEMISTRY & BIOLOGY 2003; 10:619-28. [PMID: 12890535 DOI: 10.1016/s1074-5521(03)00143-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The formation of glycoconjugates and oligosaccharides remains one of the most challenging chemical syntheses. Chemo-enzymatic routes using retaining glycosidases have been successfully harnessed but require tight kinetic or thermodynamic control. "Glycosynthases," specifically engineered glycosidases that catalyze the formation of glycosidic bonds from glycosyl donor and acceptor alcohol, are an emerging range of synthetic tools in which catalytic nucleophile mutants are harnessed together with glycosyl fluoride donors to generate powerful and versatile catalysts. Here we present the structural and kinetic dissection of the Humicola insolens Cel7B glycosynthases in which the nucleophile of the wild-type enzyme is mutated to alanine and serine (E197A and E197S). 3-D structures reveal the acceptor and donor subsites and the basis for substrate inhibition. Kinetic analysis shows that the E197S mutant is considerably more active than the corresponding alanine mutant due to a 40-fold increase in k(cat).
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Affiliation(s)
- Valérie M-A Ducros
- Structural Biology Laboratory, Department of Chemistry, The University of York, Heslington, York YO10 5YW, United Kingdom
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Béki E, Nagy I, Vanderleyden J, Jäger S, Kiss L, Fülöp L, Hornok L, Kukolya J. Cloning and heterologous expression of a beta-D-mannosidase (EC 3.2.1.25)-encoding gene from Thermobifida fusca TM51. Appl Environ Microbiol 2003; 69:1944-52. [PMID: 12676668 PMCID: PMC154781 DOI: 10.1128/aem.69.4.1944-1952.2003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2002] [Accepted: 01/03/2003] [Indexed: 11/20/2022] Open
Abstract
Thermobifida fusca TM51, a thermophilic actinomycete isolated from composted horse manure, was found to produce a number of lignocellulose-degrading hydrolases, including endoglucanases, exoglucanases, endoxylanases, beta-xylosidases, endomannanases, and beta-mannosidases, when grown on cellulose or hemicellulose as carbon sources. beta-Mannosidases (EC 3.2.1.25), although contributing to the hydrolysis of hemicellulose fractions, such as galacto-mannans, constitute a lesser-known group of the lytic enzyme systems due to their low representation in the proteins secreted by hemicellulolytic microorganisms. An expression library of T. fusca, prepared in Streptomyces lividans TK24, was screened for beta-mannosidase activity to clone genes coding for mannosidases. One positive clone was identified, and a beta-mannosidase-encoding gene (manB) was isolated. Sequence analysis of the deduced amino acid sequence of the putative ManB protein revealed substantial similarity to known mannosidases in family 2 of the glycosyl hydrolase enzymes. The calculated molecular mass of the predicted protein was 94 kDa, with an estimated pI of 4.87. S. lividans was used as heterologous expression host for the putative beta-mannosidase gene of T. fusca. The purified gene product obtained from the culture filtrate of S. lividans was then subjected to more-detailed biochemical analysis. Temperature and pH optima of the recombinant enzyme were 53 degrees C and 7.17, respectively. Substrate specificity tests revealed that the enzyme exerts only beta-D-mannosidase activity. Its kinetic parameters, determined on para-nitrophenyl beta-D-mannopyranoside (pNP-betaM) substrate were as follows: K(m) = 180 micro M and V(max) = 5.96 micro mol min(-1) mg(-1); the inhibition constant for mannose was K(i) = 5.5 mM. Glucono-lacton had no effect on the enzyme activity. A moderate trans-glycosidase activity was also observed when the enzyme was incubated in the presence of pNP-alphaM and pNP-betaM; under these conditions mannosyl groups were transferred by the enzyme from pNP-betaM to pNP-alphaM resulting in the synthesis of small amounts (1 to 2%) of disaccharides.
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Affiliation(s)
- Emese Béki
- Department of Agricultural Biotechnology and Microbiology, Szent István University, Gödöllõ, Hungary
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Abstract
The three-dimensional structure of glycosidases and of their complexes and the study of transition-state mimics reveal structural details that correlate with mechanism. Of particular interest are the transition-state conformations harnessed by individual enzymes and the substrate distortion observed in enzyme-ligand complexes. 3D-structure in synergy with transition-state mimicry opens the way for mechanistic interpretation of enzyme inhibition and for the development of therapeutic agents.
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Affiliation(s)
- Andrea Vasella
- Laboratorium für Organische Chemie, ETH Hönggerberg, HCI H317, CH-8093 Zürich, Switzerland
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