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Nekvasilová P, Kulik N, Kotik M, Petrásková L, Slámová K, Křen V, Bojarová P. Mutation Hotspot for Changing the Substrate Specificity of β- N-Acetylhexosaminidase: A Library of GlcNAcases. Int J Mol Sci 2022; 23:12456. [PMID: 36293310 PMCID: PMC9604439 DOI: 10.3390/ijms232012456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/27/2022] [Accepted: 10/12/2022] [Indexed: 12/27/2023] Open
Abstract
β-N-Acetylhexosaminidase from Talaromyces flavus (TfHex; EC 3.2.1.52) is an exo-glycosidase with dual activity for cleaving N-acetylglucosamine (GlcNAc) and N-acetylgalactosamine (GalNAc) units from carbohydrates. By targeting a mutation hotspot of the active site residue Glu332, we prepared a library of ten mutant variants with their substrate specificity significantly shifted towards GlcNAcase activity. Suitable mutations were identified by in silico methods. We optimized a microtiter plate screening method in the yeast Pichia pastoris expression system, which is required for the correct folding of tetrameric fungal β-N-acetylhexosaminidases. While the wild-type TfHex is promiscuous with its GalNAcase/GlcNAcase activity ratio of 1.2, the best single mutant variant Glu332His featured an 8-fold increase in selectivity toward GlcNAc compared with the wild-type. Several prepared variants, in particular Glu332Thr TfHex, had significantly stronger transglycosylation capabilities than the wild-type, affording longer chitooligomers - they behaved like transglycosidases. This study demonstrates the potential of mutagenesis to alter the substrate specificity of glycosidases.
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Affiliation(s)
- Pavlína Nekvasilová
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
- Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, CZ-12843 Praha 2, Czech Republic
| | - Natalia Kulik
- Laboratory of Structural Biology and Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Zámek 136, CZ-37333 Nové Hrady, Czech Republic
| | - Michael Kotik
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
| | - Lucie Petrásková
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
| | - Kristýna Slámová
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
| | - Vladimír Křen
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
| | - Pavla Bojarová
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
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Mészáros Z, Petrásková L, Kulik N, Pelantová H, Bojarová P, Křen V, Slámová K. Hypertransglycosylating Variants of the GH20 β‐
N
‐Acetylhexosaminidase for the Synthesis of Chitooligomers. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Zuzana Mészáros
- Laboratory of Biotransformation Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 Prague 4 CZ 14220 Czech Republic
- Department of Biochemistry University of Chemistry and Technology Prague Technická 6 Prague 6 CZ 16000 Czech Republic
| | - Lucie Petrásková
- Laboratory of Biotransformation Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 Prague 4 CZ 14220 Czech Republic
| | - Natalia Kulik
- Laboratory of Structural Biology and Bioinformatics Institute of Microbiology of the Czech Academy of Sciences Zámek 136 Nové Hrady CZ 37333 Czech Republic
| | - Helena Pelantová
- Laboratory of Molecular Structure Characterization Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 Prague 4 CZ 14220 Czech Republic
| | - Pavla Bojarová
- Laboratory of Biotransformation Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 Prague 4 CZ 14220 Czech Republic
| | - Vladimír Křen
- Laboratory of Biotransformation Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 Prague 4 CZ 14220 Czech Republic
| | - Kristýna Slámová
- Laboratory of Biotransformation Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 Prague 4 CZ 14220 Czech Republic
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Engineered Glycosidases for the Synthesis of Analogs of Human Milk Oligosaccharides. Int J Mol Sci 2022; 23:ijms23084106. [PMID: 35456924 PMCID: PMC9027921 DOI: 10.3390/ijms23084106] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/02/2022] [Accepted: 04/05/2022] [Indexed: 12/04/2022] Open
Abstract
Enzymatic synthesis is an elegant biocompatible approach to complex compounds such as human milk oligosaccharides (HMOs). These compounds are vital for healthy neonatal development with a positive impact on the immune system. Although HMOs may be prepared by glycosyltransferases, this pathway is often complicated by the high price of sugar nucleotides, stringent substrate specificity, and low enzyme stability. Engineered glycosidases (EC 3.2.1) represent a good synthetic alternative, especially if variations in the substrate structure are desired. Site-directed mutagenesis can improve the synthetic process with higher yields and/or increased reaction selectivity. So far, the synthesis of human milk oligosaccharides by glycosidases has mostly been limited to analytical reactions with mass spectrometry detection. The present work reveals the potential of a library of engineered glycosidases in the preparative synthesis of three tetrasaccharides derived from lacto-N-tetraose (Galβ4GlcNAcβ3Galβ4Glc), employing sequential cascade reactions catalyzed by β3-N-acetylhexosaminidase BbhI from Bifidobacterium bifidum, β4-galactosidase BgaD-B from Bacillus circulans, β4-N-acetylgalactosaminidase from Talaromyces flavus, and β3-galactosynthase BgaC from B. circulans. The reaction products were isolated and structurally characterized. This work expands the insight into the multi-step catalysis by glycosidases and shows the path to modified derivatives of complex carbohydrates that cannot be prepared by standard glycosyltransferase methods.
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Mészáros Z, Nekvasilová P, Bojarová P, Křen V, Slámová K. Reprint of: Advanced glycosidases as ingenious biosynthetic instruments. Biotechnol Adv 2021; 51:107820. [PMID: 34462167 DOI: 10.1016/j.biotechadv.2021.107820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/09/2021] [Accepted: 03/17/2021] [Indexed: 11/27/2022]
Abstract
Until recently, glycosidases, naturally hydrolyzing carbohydrate-active enzymes, have found few synthetic applications in industry, being primarily used for cleaving unwanted carbohydrates. With the establishment of glycosynthase and transglycosidase technology by genetic engineering, the view of glycosidases as industrial biotechnology tools has started to change. Their easy production, affordability, robustness, and substrate versatility, added to the possibility of controlling undesired side hydrolysis by enzyme engineering, have made glycosidases competitive synthetic tools. Current promising applications of engineered glycosidases include the production of well-defined chitooligomers, precious galactooligosaccharides or specialty chemicals such as glycosylated flavonoids. Other synthetic pathways leading to human milk oligosaccharides or remodeled antibodies are on the horizon. This work provides an overview of the synthetic achievements to date for glycosidases, emphasizing the latest trends and outlining possible developments in the field.
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Affiliation(s)
- Zuzana Mészáros
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic; Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Technická 1903/3, CZ-16628 Praha 6, Czech Republic
| | - Pavlína Nekvasilová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic; Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, CZ-12843, Praha 2, Czech Republic
| | - Pavla Bojarová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
| | - Vladimír Křen
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
| | - Kristýna Slámová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic.
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Karimi Alavijeh M, Meyer AS, Gras SL, Kentish SE. Synthesis of N-Acetyllactosamine and N-Acetyllactosamine-Based Bioactives. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:7501-7525. [PMID: 34152750 DOI: 10.1021/acs.jafc.1c00384] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
N-Acetyllactosamine (LacNAc) or more specifically β-d-galactopyranosyl-1,4-N-acetyl-d-glucosamine is a unique acyl-amino sugar and a key structural unit in human milk oligosaccharides, an antigen component of many glycoproteins, and an antiviral active component for the development of effective drugs against viruses. LacNAc is useful itself and as a basic building block for producing various bioactive oligosaccharides, notably because this synthesis may be used to add value to dairy lactose. Despite a significant amount of information in the literature on the benefits, structures, and types of different LacNAc-derived oligosaccharides, knowledge about their effective synthesis for large-scale production is still in its infancy. This work provides a comprehensive analysis of existing production strategies for LacNAc and important LacNAc-based structures, including sialylated LacNAc as well as poly- and oligo-LacNAc. We conclude that direct extraction from milk is too complex, while chemical synthesis is also impractical at an industrial scale. Microbial routes have application when multiple step reactions are needed, but the major route to large-scale biochemical production will likely lie with enzymatic routes, particularly those using β-galactosidases (for LacNAc synthesis), sialidases (for sialylated LacNAc synthesis), and β-N-acetylhexosaminidases (for oligo-LacNAc synthesis). Glycosyltransferases, especially for the biosynthesis of extended complex LacNAc structures, could also play a major role in the future. In these cases, immobilization of the enzyme can increase stability and reduce cost. Processing parameters, such as substrate concentration and purity, acceptor/donor ratio, water activity, and temperature, can affect product selectivity and yield. More work is needed to optimize these reaction parameters and in the development of robust, thermally stable enzymes to facilitate commercial production of these important bioactive substances.
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Affiliation(s)
- M Karimi Alavijeh
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - A S Meyer
- Protein Chemistry and Enzyme Technology Division, Department of Biotechnology and Biomedicine, Technical University of Denmark (DTU), DK-2800 Kongens Lyngby, Denmark
| | - S L Gras
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - S E Kentish
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
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Mészáros Z, Nekvasilová P, Bojarová P, Křen V, Slámová K. Advanced glycosidases as ingenious biosynthetic instruments. Biotechnol Adv 2021; 49:107733. [PMID: 33781890 DOI: 10.1016/j.biotechadv.2021.107733] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/09/2021] [Accepted: 03/17/2021] [Indexed: 12/22/2022]
Abstract
Until recently, glycosidases, naturally hydrolyzing carbohydrate-active enzymes, have found few synthetic applications in industry, being primarily used for cleaving unwanted carbohydrates. With the establishment of glycosynthase and transglycosidase technology by genetic engineering, the view of glycosidases as industrial biotechnology tools has started to change. Their easy production, affordability, robustness, and substrate versatility, added to the possibility of controlling undesired side hydrolysis by enzyme engineering, have made glycosidases competitive synthetic tools. Current promising applications of engineered glycosidases include the production of well-defined chitooligomers, precious galactooligosaccharides or specialty chemicals such as glycosylated flavonoids. Other synthetic pathways leading to human milk oligosaccharides or remodeled antibodies are on the horizon. This work provides an overview of the synthetic achievements to date for glycosidases, emphasizing the latest trends and outlining possible developments in the field.
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Affiliation(s)
- Zuzana Mészáros
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic; Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Technická 1903/3, CZ-16628 Praha 6, Czech Republic
| | - Pavlína Nekvasilová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic; Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, CZ-12843, Praha 2, Czech Republic
| | - Pavla Bojarová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
| | - Vladimír Křen
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic
| | - Kristýna Slámová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic.
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Nekvasilová P, Kulik N, Rychlá N, Pelantová H, Petrásková L, Bosáková Z, Cvačka J, Slámová K, Křen V, Bojarová P. How Site‐Directed Mutagenesis Boosted Selectivity of a Promiscuous Enzyme. Adv Synth Catal 2020. [DOI: 10.1002/adsc.202000604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Pavlína Nekvasilová
- Institute of Microbiology Czech Academy of Sciences Vídeňská 1083 CZ-14220 Praha 4 Czech Republic
- Department of Genetics and Microbiology Faculty of Science Charles University Viničná 5 CZ-12843 Praha 2 Czech Republic
- Department of Analytical Chemistry Faculty of Science Charles University Hlavova 2030/8. CZ-12843 Praha 2 Czech Republic
| | - Natalia Kulik
- Center for Nanobiology and Structural Biology Institute of Microbiology Czech Academy of Sciences Zámek 136 CZ-37333 Nové Hrady Czech Republic
| | - Nikola Rychlá
- Institute of Microbiology Czech Academy of Sciences Vídeňská 1083 CZ-14220 Praha 4 Czech Republic
- Department of Health Care Disciplines and Population Protection Faculty of Biomedical Engineering Czech Technical University in Prague Nám. Sítná 3105 CZ-27201 Kladno Czech Republic
| | - Helena Pelantová
- Institute of Microbiology Czech Academy of Sciences Vídeňská 1083 CZ-14220 Praha 4 Czech Republic
| | - Lucie Petrásková
- Institute of Microbiology Czech Academy of Sciences Vídeňská 1083 CZ-14220 Praha 4 Czech Republic
| | - Zuzana Bosáková
- Department of Analytical Chemistry Faculty of Science Charles University Hlavova 2030/8. CZ-12843 Praha 2 Czech Republic
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry Czech Academy of Sciences Flemingovo nám. 2 CZ-16610 Praha 6 Czech Republic
| | - Kristýna Slámová
- Institute of Microbiology Czech Academy of Sciences Vídeňská 1083 CZ-14220 Praha 4 Czech Republic
| | - Vladimír Křen
- Institute of Microbiology Czech Academy of Sciences Vídeňská 1083 CZ-14220 Praha 4 Czech Republic
| | - Pavla Bojarová
- Institute of Microbiology Czech Academy of Sciences Vídeňská 1083 CZ-14220 Praha 4 Czech Republic
- Department of Health Care Disciplines and Population Protection Faculty of Biomedical Engineering Czech Technical University in Prague Nám. Sítná 3105 CZ-27201 Kladno Czech Republic
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Kapešová J, Petrásková L, Kulik N, Straková Z, Bojarová P, Markošová K, Rebroš M, Křen V, Slámová K. Transglycosidase activity of glycosynthase-type mutants of a fungal GH20 β-N-acetylhexosaminidase. Int J Biol Macromol 2020; 161:1206-1215. [PMID: 32522540 DOI: 10.1016/j.ijbiomac.2020.05.273] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/29/2020] [Accepted: 05/20/2020] [Indexed: 02/07/2023]
Abstract
β-N-Acetylhexosaminidases (CAZy GH20, EC 3.2.1.52) are exo-glycosidases specific for cleaving N-acetylglucosamine and N-acetylgalactosamine moieties of various substrates. The β-N-acetylhexosaminidase from the filamentous fungus Talaromyces flavus (TfHex), a model enzyme in this study, has a broad substrate flexibility and outstanding synthetic ability. We have designed and characterized seven glycosynthase-type variants of TfHex mutated at the catalytic aspartate residue that stabilizes the oxazoline reaction intermediate. Most of the obtained enzyme variants lost the majority of their original hydrolytic activity towards the standard substrate p-nitrophenyl 2-acetamido-2-deoxy-β-D-glucopyranoside (pNP-β-GlcNAc); moreover, the mutants were not active with the proposed glycosynthase donor 2-acetamido-2-deoxy-d-glucopyranosyl-α-fluoride (GlcNAc-α-F) either as would be expected in a glycosynthase. Importantly, the mutant enzymes instead retained a strong transglycosylation activity towards the standard substrate pNP-β-GlcNAc. In summary, five out of seven prepared TfHex variants bearing mutation at the catalytic Asp370 residue acted as efficient transglycosidases, which makes them excellent tools for the synthesis of chitooligosaccharides, with the advantage of processing an inexpensive, stable and commercially available pNP-β-GlcNAc.
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Affiliation(s)
- Jana Kapešová
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, Prague 4 CZ 14220, Czech Republic
| | - Lucie Petrásková
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, Prague 4 CZ 14220, Czech Republic
| | - Natalia Kulik
- Center for Nanobiology and Structural Biology, Institute of Microbiology of the Czech Academy of Sciences, Zámek 136, Nové Hrady, CZ 37333, Czech Republic
| | - Zuzana Straková
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, Prague 4 CZ 14220, Czech Republic.; Department of Biochemistry, University of Chemistry and Technology Prague, Technická 6, Prague 6, CZ 16000, Czech Republic
| | - Pavla Bojarová
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, Prague 4 CZ 14220, Czech Republic
| | - Kristína Markošová
- Institute of Biotechnology, Slovak University of Technology, Radlinského 9, Bratislava, SK 81237, Slovakia
| | - Martin Rebroš
- Institute of Biotechnology, Slovak University of Technology, Radlinského 9, Bratislava, SK 81237, Slovakia
| | - Vladimír Křen
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, Prague 4 CZ 14220, Czech Republic
| | - Kristýna Slámová
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, Prague 4 CZ 14220, Czech Republic..
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Venugopal A, Mondal S, Ranganatha KS, Datta D, Kumar NS, Swamy MJ. Purification and biochemical/biophysical characterization of two hexosaminidases from the fresh water mussel, Lamellidens corrianus. Int J Biol Macromol 2020; 149:754-766. [PMID: 31987953 DOI: 10.1016/j.ijbiomac.2020.01.241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 01/18/2023]
Abstract
Two thermostable isoforms of a hexosaminidase were purified to homogeneity from the soluble extract of fresh water mussel Lamellidens corrianus, employing a variety of chromatographic techniques. Hexosaminidase A (HexA) is a heterodimer with subunit masses of ~80 and 55 kDa. Hexosaminidase B (HexB) is a homodimer with a subunit mass of 55-60 kDa. Circular dichroism spectroscopic studies indicated that both HexA and HexB contain β-sheet as the major secondary structural component with considerably lower content of α-helix. The temperature and pH optima of both the isoforms were found to be 60 °C and 4.0, respectively. The IC50 values for HexA with N-acetyl-d-galactosamine, N-acetyl-d-glucosamine, d-galactosamine, d-glucosamine, methyl α-d-mannopyranoside and d-mannose are 3.7, 72.8, 307, 216, 244 and 128 mM, respectively, whereas the corresponding IC50 values for HexB were estimated as 5.1, 61, 68, 190, 92 and 133 mM, respectively. Kinetic parameters KM and Vmax for HexA and B with p-nitrophenyl N-acetyl-β-d-glucosaminide are 4 mM, 0.23 μmol·min-1·mL-1 and 2.86 mM, 0.29 μmol·min-1·mL-1, respectively, and with p-nitrophenyl N-acetyl-β-d-galactosaminide are 4.5 mM, 0.054 μmol·min-1·mL-1 and 1.4 mM, 0.14 μmol·min-1·mL-1, respectively. GalNAc inhibited both isoforms in a non-competitive manner, whereas a mixed mode of inhibition was observed with GlcNAc with both forms.
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Affiliation(s)
| | - Saradamoni Mondal
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
| | | | - Debparna Datta
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
| | - Nadimpalli Siva Kumar
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
| | - Musti J Swamy
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India.
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Abstract
β-N-acetylhexosaminidases (EC 3.2.1.52) are retaining hydrolases of glycoside hydrolase family 20 (GH20). These enzymes catalyze hydrolysis of terminal, non-reducing N-acetylhexosamine residues, notably N-acetylglucosamine or N-acetylgalactosamine, in N-acetyl-β-D-hexosaminides. In nature, bacterial β-N-acetylhexosaminidases are mainly involved in cell wall peptidoglycan synthesis, analogously, fungal β-N-acetylhexosaminidases act on cell wall chitin. The enzymes work via a distinct substrate-assisted mechanism that utilizes the 2-acetamido group as nucleophile. Curiously, the β-N-acetylhexosaminidases possess an inherent trans-glycosylation ability which is potentially useful for biocatalytic synthesis of functional carbohydrates, including biomimetic synthesis of human milk oligosaccharides and other glycan-functionalized compounds. In this review, we summarize the reaction engineering approaches (donor substrate activation, additives, and reaction conditions) that have proven useful for enhancing trans-glycosylation activity of GH20 β-N-acetylhexosaminidases. We provide comprehensive overviews of reported synthesis reactions with GH20 enzymes, including tables that list the specific enzyme used, donor and acceptor substrates, reaction conditions, and details of the products and yields obtained. We also describe the active site traits and mutations that appear to favor trans-glycosylation activity of GH20 β-N-acetylhexosaminidases. Finally, we discuss novel protein engineering strategies and suggest potential “hotspots” for mutations to promote trans-glycosylation activity in GH20 for efficient synthesis of specific functional carbohydrates and other glyco-engineered products.
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A novel enzymatic tool for transferring GalNAc moiety onto challenging acceptors. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140319. [DOI: 10.1016/j.bbapap.2019.140319] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/15/2019] [Accepted: 10/28/2019] [Indexed: 12/31/2022]
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Identification and Characterization of a β- N-Acetylhexosaminidase with a Biosynthetic Activity from the Marine Bacterium Paraglaciecola hydrolytica S66 T. Int J Mol Sci 2020; 21:ijms21020417. [PMID: 31936522 PMCID: PMC7014002 DOI: 10.3390/ijms21020417] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 01/04/2020] [Accepted: 01/07/2020] [Indexed: 11/24/2022] Open
Abstract
β-N-Acetylhexosaminidases are glycoside hydrolases (GHs) acting on N-acetylated carbohydrates and glycoproteins with the release of N-acetylhexosamines. Members of the family GH20 have been reported to catalyze the transfer of N-acetylglucosamine (GlcNAc) to an acceptor, i.e., the reverse of hydrolysis, thus representing an alternative to chemical oligosaccharide synthesis. Two putative GH20 β-N-acetylhexosaminidases, PhNah20A and PhNah20B, encoded by the marine bacterium Paraglaciecola hydrolytica S66T, are distantly related to previously characterized enzymes. Remarkably, PhNah20A was located by phylogenetic analysis outside clusters of other studied β-N-acetylhexosaminidases, in a unique position between bacterial and eukaryotic enzymes. We successfully produced recombinant PhNah20A showing optimum activity at pH 6.0 and 50 °C, hydrolysis of GlcNAc β-1,4 and β-1,3 linkages in chitobiose (GlcNAc)2 and GlcNAc-1,3-β-Gal-1,4-β-Glc (LNT2), a human milk oligosaccharide core structure. The kinetic parameters of PhNah20A for p-nitrophenyl-GlcNAc and p-nitrophenyl-GalNAc were highly similar: kcat/KM being 341 and 344 mM−1·s−1, respectively. PhNah20A was unstable in dilute solution, but retained full activity in the presence of 0.5% bovine serum albumin (BSA). PhNah20A catalyzed the formation of LNT2, the non-reducing trisaccharide β-Gal-1,4-β-Glc-1,1-β-GlcNAc, and in low amounts the β-1,2- or β-1,3-linked trisaccharide β-Gal-1,4(β-GlcNAc)-1,x-Glc by a transglycosylation of lactose using 2-methyl-(1,2-dideoxy-α-d-glucopyrano)-oxazoline (NAG-oxazoline) as the donor. PhNah20A is the first characterized member of a distinct subgroup within GH20 β-N-acetylhexosaminidases.
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Chen X, Jin L, Jiang X, Guo L, Gu G, Xu L, Lu L, Wang F, Xiao M. Converting a β-N-acetylhexosaminidase into two trans-β-N-acetylhexosaminidases by domain-targeted mutagenesis. Appl Microbiol Biotechnol 2019; 104:661-673. [PMID: 31822984 DOI: 10.1007/s00253-019-10253-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/29/2019] [Accepted: 11/12/2019] [Indexed: 01/14/2023]
Abstract
We have recently derived a β-N-acetylhexosaminidase, BbhI, from Bifidobacterium bifidum JCM 1254, which could regioselectively synthesize GlcNAcβ1-3Galβ1-4Glc with a yield of 44.9%. Here, directed evolution of BbhI by domain-targeted mutagenesis was carried out. Firstly, the GH20 domain was selected for random mutagenesis using MEGAWHOP method and a small library of 1300 clones was created. A total of 734 colonies with reduced hydrolytic activity were isolated, and three mutants with elevated transglycosylation yields, GlcNAcβ1-3Galβ1-4Glc yields of 68.5%, 74.7%, and 81.1%, respectively, were obtained. Subsequently, nineteen independent mutants were constructed according to all the mutation sites in these three mutants. After transglycosylation analysis, Asp714 and Trp773 were identified as key residues for improvement in transglycosylation ability and were chosen for the second round of directed evolution by site-saturation mutagenesis. Two most efficient mutants D714T and W773R that acted as trans-β-N-acetylhexosaminidase were finally achieved. D714T with the substitution at the putative nucleophile assistant residue Asp714 by threonine showed high yield of 84.7% with unobserved hydrolysis towards transglycosylation product. W773R with arginine substitution at Trp773 residue locating at the entrance of catalytic cavity led to the yield up to 81.8%. The kcat/Km values of D714T and W773R for hydrolysis of pNP-β-GlcNAc displayed drastic decreases. NMR investigation of protein-substrate interaction revealed an invariable mode of the catalytic cavity of D714T, W773R, and WT BbhI. The collective motions of protein model showed the mutations Thr714 and Arg773 exerted little effect on the dynamics of the inside but a large effect on the dynamics of the outside of catalytic cavity.
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Affiliation(s)
- Xiaodi Chen
- State Key Lab of Microbial Technology, National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, 266237, People's Republic of China.,School of Pharmaceutical Sciences, Shandong University, Jinan, 250012, People's Republic of China
| | - Lan Jin
- State Key Lab of Microbial Technology, National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Xukai Jiang
- State Key Lab of Microbial Technology, National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Longcheng Guo
- State Key Lab of Microbial Technology, National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Guofeng Gu
- State Key Lab of Microbial Technology, National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Li Xu
- State Key Lab of Microbial Technology, National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Lili Lu
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Fengshan Wang
- School of Pharmaceutical Sciences, Shandong University, Jinan, 250012, People's Republic of China
| | - Min Xiao
- State Key Lab of Microbial Technology, National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, 266237, People's Republic of China.
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Acceptor Specificity of β- N-Acetylhexosaminidase from Talaromyces flavus: A Rational Explanation. Int J Mol Sci 2019; 20:ijms20246181. [PMID: 31817903 PMCID: PMC6940953 DOI: 10.3390/ijms20246181] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/03/2019] [Accepted: 12/05/2019] [Indexed: 01/08/2023] Open
Abstract
Fungal β-N-acetylhexosaminidases, though hydrolytic enzymes in vivo, are useful tools in the preparation of oligosaccharides of biological interest. The β-N-acetylhexosaminidase from Talaromyces flavus is remarkable in terms of its synthetic potential, broad substrate specificity, and tolerance to substrate modifications. It can be heterologously produced in Pichia pastoris in a high yield. The mutation of the Tyr470 residue to histidine greatly enhances its transglycosylation capability. The aim of this work was to identify the structural requirements of this model β-N-acetylhexosaminidase for its transglycosylation acceptors and formulate a structure-activity relationship study. Enzymatic reactions were performed using an activated glycosyl donor, 4-nitrophenyl N-acetyl-β-d-glucosaminide or 4-nitrophenyl N-acetyl-β-d-galactosaminide, and a panel of glycosyl acceptors of varying structural features (N-acetylglucosamine, glucose, N-acetylgalactosamine, galactose, N-acetylmuramic acid, and glucuronic acid). The transglycosylation products were isolated and structurally characterized. The C-2 N-acetamido group in the acceptor molecule was found to be essential for recognition by the enzyme. The presence of the C-2 hydroxyl moiety strongly hindered the normal course of transglycosylation, yielding unique non-reducing disaccharides in a low yield. Moreover, whereas the gluco-configuration at C-4 steered the glycosylation into the β(1-4) position, the galacto-acceptor afforded a β(1-6) glycosidic linkage. The Y470H mutant enzyme was tested with acceptors based on β-glycosides of uronic acid and N-acetylmuramic acid. With the latter acceptor, we were able to isolate and characterize one glycosylation product in a low yield. To our knowledge, this is the first example of enzymatic glycosylation of an N-acetylmuramic acid derivative. In order to explain these findings and predict enzyme behavior, a modeling study was accomplished that correlated with the acquired experimental data.
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β-N-Acetylhexosaminidases-the wizards of glycosylation. Appl Microbiol Biotechnol 2019; 103:7869-7881. [PMID: 31401752 DOI: 10.1007/s00253-019-10065-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 12/27/2022]
Abstract
β-N-Acetylhexosaminidases (EC 3.2.1.52) are a unique family of glycoside hydrolases with dual substrate specificity and a particular reaction mechanism. Though hydrolytic enzymes per se, their good stability, easy recombinant production, absolute stereoselectivity, and a broad substrate specificity predestine these enzymes for challenging applications in carbohydrate synthesis. This mini-review aims to demonstrate the catalytic potential of β-N-acetylhexosaminidases in a range of unusual reactions, processing of unnatural substrates, formation of unexpected products, and demanding reaction designs. The use of unconventional media can considerably alter the progress of transglycosylation reactions. By means of site-directed mutagenesis, novel catalytic machineries can be constructed. Glycosylation of difficult substrates such as sugar nucleotides was accomplished, and the range of afforded glycosidic bonds comprises unique non-reducing sugars. Specific functional groups may be tolerated in the substrate molecule, which makes β-N-acetylhexosaminidases invaluable allies in difficult synthetic problems.
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Bassanini I, Kapešová J, Petrásková L, Pelantová H, Markošová K, Rebroš M, Valentová K, Kotik M, Káňová K, Bojarová P, Cvačka J, Turková L, Ferrandi EE, Bayout I, Riva S, Křen V. Glycosidase‐Catalyzed Synthesis of Glycosyl Esters and Phenolic Glycosides of Aromatic Acids. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900259] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Ivan Bassanini
- Istituto di Chimica del Riconoscimento MolecolareConsiglio Nazionale delle Ricerche Via Mario Bianco 9 I 20131 Milano Italy
- Dipartimento di Scienze FarmaceuticheUniversità degli Studi di Milano Via Mangiagalli 25 I 20131 Milano Italy
| | - Jana Kapešová
- Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague 4 Czech Republic
| | - Lucie Petrásková
- Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague 4 Czech Republic
| | - Helena Pelantová
- Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague 4 Czech Republic
| | - Kristína Markošová
- Institute of BiotechnologySlovak University of Technology Radlinského 9 SK 81237 Bratislava Slovakia
| | - Martin Rebroš
- Institute of BiotechnologySlovak University of Technology Radlinského 9 SK 81237 Bratislava Slovakia
| | - Kateřina Valentová
- Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague 4 Czech Republic
| | - Michael Kotik
- Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague 4 Czech Republic
| | - Kristýna Káňová
- Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague 4 Czech Republic
| | - Pavla Bojarová
- Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague 4 Czech Republic
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry of theCzech Academy of Sciences Flemingovo nám. 2 CZ 16610 Prague 6 Czech Republic
| | - Lucie Turková
- Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague 4 Czech Republic
| | - Erica E. Ferrandi
- Istituto di Chimica del Riconoscimento MolecolareConsiglio Nazionale delle Ricerche Via Mario Bianco 9 I 20131 Milano Italy
| | - Ikram Bayout
- Istituto di Chimica del Riconoscimento MolecolareConsiglio Nazionale delle Ricerche Via Mario Bianco 9 I 20131 Milano Italy
- Asymmetric Catalysis Laboratory (LCAE)Badji Mokhtar Annaba-University B.P. 12 23000 Annaba Algeria
| | - Sergio Riva
- Istituto di Chimica del Riconoscimento MolecolareConsiglio Nazionale delle Ricerche Via Mario Bianco 9 I 20131 Milano Italy
| | - Vladimír Křen
- Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague 4 Czech Republic
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Bojarová P, Kulik N, Hovorková M, Slámová K, Pelantová H, Křen V. The β- N-Acetylhexosaminidase in the Synthesis of Bioactive Glycans: Protein and Reaction Engineering. Molecules 2019; 24:molecules24030599. [PMID: 30743988 PMCID: PMC6384963 DOI: 10.3390/molecules24030599] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 02/04/2019] [Accepted: 02/06/2019] [Indexed: 01/05/2023] Open
Abstract
N-Acetylhexosamine oligosaccharides terminated with GalNAc act as selective ligands of galectin-3, a biomedically important human lectin. Their synthesis can be accomplished by β-N-acetylhexosaminidases (EC 3.2.1.52). Advantageously, these enzymes tolerate the presence of functional groups in the substrate molecule, such as the thiourea linker useful for covalent conjugation of glycans to a multivalent carrier, affording glyconjugates. β-N-Acetylhexosaminidases exhibit activity towards both N-acetylglucosamine (GlcNAc) and N-acetylgalactosamine (GalNAc) moieties. A point mutation of active-site amino acid Tyr into other amino acid residues, especially Phe, His, and Asn, has previously been shown to strongly suppress the hydrolytic activity of β-N-acetylhexosaminidases, creating enzymatic synthetic engines. In the present work, we demonstrate that Tyr470 is an important mutation hotspot for altering the ratio of GlcNAcase/GalNAcase activity, resulting in mutant enzymes with varying affinity to GlcNAc/GalNAc substrates. The enzyme selectivity may additionally be manipulated by altering the reaction medium upon changing pH or adding selected organic co-solvents. As a result, we are able to fine-tune the β-N-acetylhexosaminidase affinity and selectivity, resulting in a high-yield production of the functionalized GalNAcβ4GlcNAc disaccharide, a selective ligand of galectin-3.
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Affiliation(s)
- Pavla Bojarová
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic.
| | - Natalia Kulik
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Sciences, Zámek 136, CZ-37333 Nové Hrady, Czech Republic.
| | - Michaela Hovorková
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic.
| | - Kristýna Slámová
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic.
| | - Helena Pelantová
- Laboratory of Molecular Structure Characterization, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic.
| | - Vladimír Křen
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Praha 4, Czech Republic.
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18
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Bojarová P, Tavares MR, Laaf D, Bumba L, Petrásková L, Konefał R, Bláhová M, Pelantová H, Elling L, Etrych T, Chytil P, Křen V. Biocompatible glyconanomaterials based on HPMA-copolymer for specific targeting of galectin-3. J Nanobiotechnology 2018; 16:73. [PMID: 30236114 PMCID: PMC6146777 DOI: 10.1186/s12951-018-0399-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 09/11/2018] [Indexed: 01/01/2023] Open
Abstract
Background Galectin-3 (Gal-3) is a promising target in cancer therapy with a high therapeutic potential due to its abundant localization within the tumor tissue and its involvement in tumor development and proliferation. Potential clinical application of Gal-3-targeted inhibitors is often complicated by their insufficient selectivity or low biocompatibility. Nanomaterials based on N-(2-hydroxypropyl)methacrylamide (HPMA) nanocarrier are attractive for in vivo application due to their good water solubility and lack of toxicity and immunogenicity. Their conjugation with tailored carbohydrate ligands can yield specific glyconanomaterials applicable for targeting biomedicinally relevant lectins like Gal-3. Results In the present study we describe the synthesis and the structure-affinity relationship study of novel Gal-3-targeted glyconanomaterials, based on hydrophilic HPMA nanocarriers. HPMA nanocarriers decorated with varying amounts of Gal-3 specific epitope GalNAcβ1,4GlcNAc (LacdiNAc) were analyzed in a competitive ELISA-type assay and their binding kinetics was described by surface plasmon resonance. We showed the impact of various linker types and epitope distribution on the binding affinity to Gal-3. The synthesis of specific functionalized LacdiNAc epitopes was accomplished under the catalysis by mutant β-N-acetylhexosaminidases. The glycans were conjugated to statistic HPMA copolymer precursors through diverse linkers in a defined pattern and density using Cu(I)-catalyzed azide–alkyne cycloaddition. The resulting water-soluble and structurally flexible synthetic glyconanomaterials exhibited affinity to Gal-3 in low μM range. Conclusions The results of this study reveal the relation between the linker structure, glycan distribution and the affinity of the glycopolymer nanomaterial to Gal-3. They pave the way to specific biomedicinal glyconanomaterials that target Gal-3 as a therapeutic goal in cancerogenesis and other disorders. Electronic supplementary material The online version of this article (10.1186/s12951-018-0399-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- P Bojarová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic.
| | - M R Tavares
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovský Sq. 2, 16206, Prague 6, Czech Republic
| | - D Laaf
- Laboratory for Biomaterials, Institute for Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstraße 20, 52074, Aachen, Germany
| | - L Bumba
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - L Petrásková
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - R Konefał
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovský Sq. 2, 16206, Prague 6, Czech Republic
| | - M Bláhová
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovský Sq. 2, 16206, Prague 6, Czech Republic
| | - H Pelantová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - L Elling
- Laboratory for Biomaterials, Institute for Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstraße 20, 52074, Aachen, Germany
| | - T Etrych
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovský Sq. 2, 16206, Prague 6, Czech Republic
| | - P Chytil
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovský Sq. 2, 16206, Prague 6, Czech Republic.
| | - V Křen
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
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Slámová K, Kapešová J, Valentová K. "Sweet Flavonoids": Glycosidase-Catalyzed Modifications. Int J Mol Sci 2018; 19:E2126. [PMID: 30037103 PMCID: PMC6073497 DOI: 10.3390/ijms19072126] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 01/27/2023] Open
Abstract
Natural flavonoids, especially in their glycosylated forms, are the most abundant phenolic compounds found in plants, fruit, and vegetables. They exhibit a large variety of beneficial physiological effects, which makes them generally interesting in a broad spectrum of scientific areas. In this review, we focus on recent advances in the modifications of the glycosidic parts of various flavonoids employing glycosidases, covering both selective trimming of the sugar moieties and glycosylation of flavonoid aglycones by natural and mutant glycosidases. Glycosylation of flavonoids strongly enhances their water solubility and thus increases their bioavailability. Antioxidant and most biological activities are usually less pronounced in glycosides, but some specific bioactivities are enhanced. The presence of l-rhamnose (6-deoxy-α-l-mannopyranose) in rhamnosides, rutinosides (rutin, hesperidin) and neohesperidosides (naringin) plays an important role in properties of flavonoid glycosides, which can be considered as "pro-drugs". The natural hydrolytic activity of glycosidases is widely employed in biotechnological deglycosylation processes producing respective aglycones or partially deglycosylated flavonoids. Moreover, deglycosylation is quite commonly used in the food industry aiming at the improvement of sensoric properties of beverages such as debittering of citrus juices or enhancement of wine aromas. Therefore, natural and mutant glycosidases are excellent tools for modifications of flavonoid glycosides.
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Affiliation(s)
- Kristýna Slámová
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Prague 4, Czech Republic.
| | - Jana Kapešová
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Prague 4, Czech Republic.
| | - Kateřina Valentová
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-14220 Prague 4, Czech Republic.
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Revisiting glycoside hydrolase family 20 β-N-acetyl-d-hexosaminidases: Crystal structures, physiological substrates and specific inhibitors. Biotechnol Adv 2018; 36:1127-1138. [DOI: 10.1016/j.biotechadv.2018.03.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/18/2018] [Accepted: 03/19/2018] [Indexed: 12/31/2022]
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21
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Slámová K, Bojarová P. Engineered N-acetylhexosamine-active enzymes in glycoscience. Biochim Biophys Acta Gen Subj 2017; 1861:2070-2087. [PMID: 28347843 DOI: 10.1016/j.bbagen.2017.03.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/21/2017] [Accepted: 03/23/2017] [Indexed: 01/17/2023]
Abstract
BACKGROUND In recent years, enzymes modifying N-acetylhexosamine substrates have emerged in numerous theoretical studies as well as practical applications from biology, biomedicine, and biotechnology. Advanced enzyme engineering techniques converted them into potent synthetic instruments affording a variety of valuable glycosides. SCOPE OF REVIEW This review presents the diversity of engineered enzymes active with N-acetylhexosamine carbohydrates: from popular glycoside hydrolases and glycosyltransferases to less known oxidases, epimerases, kinases, sulfotransferases, and acetylases. Though hydrolases in natura, engineered chitinases, β-N-acetylhexosaminidases, and endo-β-N-acetylglucosaminidases were successfully employed in the synthesis of defined natural and derivatized chitooligomers and in the remodeling of N-glycosylation patterns of therapeutic antibodies. The genes of various N-acetylhexosaminyltransferases were cloned into metabolically engineered microorganisms for producing human milk oligosaccharides, Lewis X structures, and human-like glycoproteins. Moreover, mutant N-acetylhexosamine-active glycosyltransferases were applied, e.g., in the construction of glycomimetics and complex glycostructures, industrial production of low-lactose milk, and metabolic labeling of glycans. In the synthesis of biotechnologically important compounds, several innovative glycoengineered systems are presented for an efficient bioproduction of GlcNAc, UDP-GlcNAc, N-acetylneuraminic acid, and of defined glycosaminoglycans. MAJOR CONCLUSIONS The above examples demonstrate that engineering of N-acetylhexosamine-active enzymes was able to solve complex issues such as synthesis of tailored human-like glycoproteins or industrial-scale production of desired oligosaccharides. Due to the specific catalytic mechanism, mutagenesis of these catalysts was often realized through rational solutions. GENERAL SIGNIFICANCE Specific N-acetylhexosamine glycosylation is crucial in biological, biomedical and biotechnological applications and a good understanding of its details opens new possibilities in this fast developing area of glycoscience.
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Affiliation(s)
- Kristýna Slámová
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ 14220 Prague 4, Czech Republic
| | - Pavla Bojarová
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ 14220 Prague 4, Czech Republic.
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22
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Efficient and Regioselective Synthesis of β-GalNAc/GlcNAc-Lactose by a Bifunctional Transglycosylating β-N-Acetylhexosaminidase from Bifidobacterium bifidum. Appl Environ Microbiol 2016; 82:5642-52. [PMID: 27422836 DOI: 10.1128/aem.01325-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 06/29/2016] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED β-N-Acetylhexosaminidases have attracted interest particularly for oligosaccharide synthesis, but their use remains limited by the rarity of enzyme sources , low efficiency, and relaxed regioselectivity of transglycosylation. In this work, genes of 13 β-N-acetylhexosaminidases, including 5 from Bacteroides fragilis ATCC 25285, 5 from Clostridium perfringens ATCC 13124, and 3 from Bifidobacterium bifidum JCM 1254, were cloned and heterogeneously expressed in Escherichia coli The resulting recombinant enzymes were purified and screened for transglycosylation activity. A β-N-acetylhexosaminidase named BbhI, which belongs to glycoside hydrolase family 20 and was obtained from B. bifidum JCM 1254, possesses the bifunctional property of efficiently transferring both GalNAc and GlcNAc residues through β1-3 linkage to the Gal residue of lactose. The effects of initial substrate concentration, pH, temperature, and reaction time on transglycosylation activities of BbhI were studied in detail. With the use of 10 mM pNP-β-GalNAc or 20 mM pNP-β-GlcNAc as the donor and 400 mM lactose as the acceptor in phosphate buffer (pH 5.8), BbhI synthesized GalNAcβ1-3Galβ1-4Glc and GlcNAcβ1-3Galβ1-4Glc at maximal yields of 55.4% at 45°C and 4 h and 44.9% at 55°C and 1.5 h, respectively. The model docking of BbhI with lactose showed the possible molecular basis of strict regioselectivity of β1-3 linkage in β-N-acetylhexosaminyl lactose synthesis. IMPORTANCE Oligosaccharides play a crucial role in many biological events and therefore are promising potential therapeutic agents. However, their use is limited because large-scale production of oligosaccharides is difficult. The chemical synthesis requires multiple protecting group manipulations to control the regio- and stereoselectivity of glycosidic bonds. In comparison, enzymatic synthesis can produce oligosaccharides in one step by using glycosyltransferases and glycosidases. Given the lower price of their glycosyl donor and their broader acceptor specificity, glycosidases are more advantageous than glycosyltransferases for large-scale synthesis. β-N-Acetylhexosaminidases have attracted interest particularly for β-N-acetylhexosaminyl oligosaccharide synthesis, but their application is affected by having few enzyme sources, low efficiency, and relaxed regioselectivity of transglycosylation. In this work, we describe a microbial β-N-acetylhexosaminidase that exhibited strong transglycosylation activity and strict regioselectivity for β-N-acetylhexosaminyl lactose synthesis and thus provides a powerful synthetic tool to obtain biologically important GalNAcβ1-3Lac and GlcNAcβ1-3Lac.
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Slámová K, Krejzová J, Marhol P, Kalachova L, Kulik N, Pelantová H, Cvačka J, Křen V. Synthesis of Derivatized Chitooligomers using Transglycosidases Engineered from the Fungal GH20 β-N-Acetylhexosaminidase. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500075] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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24
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Kulik N, Slámová K, Ettrich R, Křen V. Computational study of β-N-acetylhexosaminidase from Talaromyces flavus, a glycosidase with high substrate flexibility. BMC Bioinformatics 2015; 16:28. [PMID: 25627923 PMCID: PMC4384365 DOI: 10.1186/s12859-015-0465-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/15/2015] [Indexed: 01/17/2023] Open
Abstract
Background β-N-Acetylhexosaminidase (GH20) from the filamentous fungus Talaromyces flavus, previously identified as a prominent enzyme in the biosynthesis of modified glycosides, lacks a high resolution three-dimensional structure so far. Despite of high sequence identity to previously reported Aspergillus oryzae and Penicilluim oxalicum β-N-acetylhexosaminidases, this enzyme tolerates significantly better substrate modification. Understanding of key structural features, prediction of effective mutants and potential substrate characteristics prior to their synthesis are of general interest. Results Computational methods including homology modeling and molecular dynamics simulations were applied to shad light on the structure-activity relationship in the enzyme. Primary sequence analysis revealed some variable regions able to influence difference in substrate affinity of hexosaminidases. Moreover, docking in combination with consequent molecular dynamics simulations of C-6 modified glycosides enabled us to identify the structural features required for accommodation and processing of these bulky substrates in the active site of hexosaminidase from T. flavus. To access the reliability of predictions on basis of the reported model, all results were confronted with available experimental data that demonstrated the principal correctness of the predictions as well as the model. Conclusions The main variable regions in β-N-acetylhexosaminidases determining difference in modified substrate affinity are located close to the active site entrance and engage two loops. Differences in primary sequence and the spatial arrangement of these loops and their interplay with active site amino acids, reflected by interaction energies and dynamics, account for the different catalytic activity and substrate specificity of the various fungal and bacterial β-N-acetylhexosaminidases. Electronic supplementary material The online version of this article (doi:10.1186/s12859-015-0465-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Natallia Kulik
- Department of Structure and Function of Proteins, Institute of Nanobiology and Structural Biology of GCRC, Academy of Sciences of the Czech Republic, Zamek 136, 37333, Nove Hrady, Czech Republic.
| | - Kristýna Slámová
- Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Videnska 1083, 14220, Praha 4, Czech Republic.
| | - Rüdiger Ettrich
- Department of Structure and Function of Proteins, Institute of Nanobiology and Structural Biology of GCRC, Academy of Sciences of the Czech Republic, Zamek 136, 37333, Nove Hrady, Czech Republic. .,Faculty of Sciences, University of South Bohemia in Ceske Budejovice, Zamek 136, 37333, Nove Hrady, Czech Republic.
| | - Vladimír Křen
- Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Videnska 1083, 14220, Praha 4, Czech Republic.
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Krejzová J, Kalachova L, Šimon P, Pelantová H, Slámová K, Křen V. Inhibition of microbial β-N-acetylhexosaminidases by 4-deoxy- and galacto-analogues of NAG-thiazoline. Bioorg Med Chem Lett 2014; 24:5321-3. [PMID: 25442323 DOI: 10.1016/j.bmcl.2014.09.066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/11/2014] [Accepted: 09/12/2014] [Indexed: 11/24/2022]
Abstract
NAG-thiazoline is a well-established competitive inhibitor of two physiologically relevant glycosidase families-β-N-acetylhexosaminidases (GH20) and β-N-acetylglucosaminidases (GH84). Based on the different substrate flexibilities of these enzyme groups, we designed and synthesized the 4-deoxy derivative of NAG-thiazoline aiming at the selective inhibition of GH20 β-N-acetylhexosaminidases. One GH84 and two GH20 microbial glycosidases were employed as model enzymes for the inhibition assays. Surprisingly, the new compound 4-deoxy-thiazoline exhibited no activity inhibition with either of the enzyme families of interest. Unlike with the substrates, the 4-hydroxyl group of the inhibitor's sugar ring seems to be crucial for binding the inhibitor to the active sites of these enzymes.
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Affiliation(s)
- Jana Krejzová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 14220 Praha 4, Czech Republic; Department of Biochemistry and Microbiology, Institute of Chemical Technology Prague, Technická 5, CZ 16628 Praha 6, Czech Republic
| | - Lubica Kalachova
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 14220 Praha 4, Czech Republic
| | - Petr Šimon
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 14220 Praha 4, Czech Republic
| | - Helena Pelantová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 14220 Praha 4, Czech Republic
| | - Kristýna Slámová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 14220 Praha 4, Czech Republic.
| | - Vladimír Křen
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 14220 Praha 4, Czech Republic
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Nyyssönen M, Tran HM, Karaoz U, Weihe C, Hadi MZ, Martiny JBH, Martiny AC, Brodie EL. Coupled high-throughput functional screening and next generation sequencing for identification of plant polymer decomposing enzymes in metagenomic libraries. Front Microbiol 2013; 4:282. [PMID: 24069019 PMCID: PMC3779933 DOI: 10.3389/fmicb.2013.00282] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 09/02/2013] [Indexed: 12/13/2022] Open
Abstract
Recent advances in sequencing technologies generate new predictions and hypotheses about the functional roles of environmental microorganisms. Yet, until we can test these predictions at a scale that matches our ability to generate them, most of them will remain as hypotheses. Function-based mining of metagenomic libraries can provide direct linkages between genes, metabolic traits and microbial taxa and thus bridge this gap between sequence data generation and functional predictions. Here we developed high-throughput screening assays for function-based characterization of activities involved in plant polymer decomposition from environmental metagenomic libraries. The multiplexed assays use fluorogenic and chromogenic substrates, combine automated liquid handling and use a genetically modified expression host to enable simultaneous screening of 12,160 clones for 14 activities in a total of 170,240 reactions. Using this platform we identified 374 (0.26%) cellulose, hemicellulose, chitin, starch, phosphate and protein hydrolyzing clones from fosmid libraries prepared from decomposing leaf litter. Sequencing on the Illumina MiSeq platform, followed by assembly and gene prediction of a subset of 95 fosmid clones, identified a broad range of bacterial phyla, including Actinobacteria, Bacteroidetes, multiple Proteobacteria sub-phyla in addition to some Fungi. Carbohydrate-active enzyme genes from 20 different glycoside hydrolase (GH) families were detected. Using tetranucleotide frequency (TNF) binning of fosmid sequences, multiple enzyme activities from distinct fosmids were linked, demonstrating how biochemically-confirmed functional traits in environmental metagenomes may be attributed to groups of specific organisms. Overall, our results demonstrate how functional screening of metagenomic libraries can be used to connect microbial functionality to community composition and, as a result, complement large-scale metagenomic sequencing efforts.
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Affiliation(s)
- Mari Nyyssönen
- Ecology Department, Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA
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Angling for uniqueness in enzymatic preparation of glycosides. Biomolecules 2013; 3:334-50. [PMID: 24970171 PMCID: PMC4030847 DOI: 10.3390/biom3020334] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 05/23/2013] [Accepted: 06/03/2013] [Indexed: 02/06/2023] Open
Abstract
In the early days of biocatalysis, limitations of an enzyme modeled the enzymatic applications; nowadays the enzyme can be engineered to be suitable for the process requirements. This is a general bird's-eye view and as such cannot be specific for articulated situations found in different classes of enzymes or for selected enzymatic processes. As far as the enzymatic preparation of glycosides is concerned, recent scientific literature is awash with examples of uniqueness related to the features of the biocatalyst (yield, substrate specificity, regioselectivity, and resistance to a particular reaction condition). The invention of glycosynthases is just one of the aspects that has thrust forward the research in this field. Protein engineering, metagenomics and reaction engineering have led to the discovery of an expanding number of novel enzymes and to the setting up of new bio-based processes for the preparation of glycosides. In this review, new examples from the last decade are compiled with attention both to cases in which naturally present, as well as genetically inserted, characteristics of the catalysts make them attractive for biocatalysis.
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Krejzová J, Šimon P, Vavříková E, Slámová K, Pelantová H, Riva S, Spiwok V, Křen V. Enzymatic synthesis of new C-6-acylated derivatives of NAG-thiazoline and evaluation of their inhibitor activities towards fungal β-N-acetylhexosaminidase. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcatb.2012.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Carbohydrate synthesis and biosynthesis technologies for cracking of the glycan code: recent advances. Biotechnol Adv 2012; 31:17-37. [PMID: 22484115 DOI: 10.1016/j.biotechadv.2012.03.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 03/06/2012] [Accepted: 03/20/2012] [Indexed: 12/22/2022]
Abstract
The glycan code of glycoproteins can be conceptually defined at molecular level by the sequence of well characterized glycans attached to evolutionarily predetermined amino acids along the polypeptide chain. Functional consequences of protein glycosylation are numerous, and include a hierarchy of properties from general physicochemical characteristics such as solubility, stability and protection of the polypeptide from the environment up to specific glycan interactions. Definition of the glycan code for glycoproteins has been so far hampered by the lack of chemically defined glycoprotein glycoforms that proved to be extremely difficult to purify from natural sources, and the total chemical synthesis of which has been hitherto possible only for very small molecular species. This review summarizes the recent progress in chemical and chemoenzymatic synthesis of complex glycans and their protein conjugates. Progress in our understanding of the ways in which a particular glycoprotein glycoform gives rise to a unique set of functional properties is now having far reaching implications for the biotechnology of important glycodrugs such as therapeutical monoclonal antibodies, glycoprotein hormones, carbohydrate conjugates used for vaccination and other practically important protein-carbohydrate conjugates.
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Slámová K, Bojarová P, Gerstorferová D, Fliedrová B, Hofmeisterová J, Fiala M, Pompach P, Křen V. Sequencing, cloning and high-yield expression of a fungal β-N-acetylhexosaminidase in Pichia pastoris. Protein Expr Purif 2012; 82:212-7. [PMID: 22266368 DOI: 10.1016/j.pep.2012.01.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/02/2012] [Accepted: 01/04/2012] [Indexed: 11/25/2022]
Abstract
The β-N-acetylhexosaminidase from Talaromyces flavus has a remarkable synthetic ability, processing even carbohydrates with various functionalities. Its broader use is partially hampered by low-yield production in the native fungus. Here, we present an optimized 3-day production of this enzyme in the eukaryotic host of Pichia pastoris, in ca 10-fold higher volume activity (10 U/ml) and close-to-perfect purity (one chromatographic step needed). Importantly, the recombinant enzyme features the same biochemical and catalytic properties, including the syntheses with derivatized carbohydrate substrates. This is the first example of the overexpression of a fungal β-N-acetylhexosaminidase by a single-cell producer in liquid medium. It represents a promising solution for wider biotechnological applications of this outstanding enzyme.
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Affiliation(s)
- Kristýna Slámová
- Institute of Microbiology, Center for Biocatalysis and Biotransformation, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 14220, Prague 4, Czech Republic
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Drozdová A, Bojarová P, Křenek K, Weignerová L, Henßen B, Elling L, Christensen H, Jensen HH, Pelantová H, Kuzma M, Bezouška K, Krupová M, Adámek D, Slámová K, Křen V. Enzymatic synthesis of dimeric glycomimetic ligands of NK cell activation receptors. Carbohydr Res 2011; 346:1599-609. [DOI: 10.1016/j.carres.2011.04.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/20/2011] [Accepted: 04/27/2011] [Indexed: 10/18/2022]
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Bojarová P, Slámová K, Křenek K, Gažák R, Kulik N, Ettrich R, Pelantová H, Kuzma M, Riva S, Adámek D, Bezouška K, Křen V. Charged Hexosaminides as New Substrates for β-N-Acetylhexosaminidase-Catalyzed Synthesis of Immunomodulatory Disaccharides. Adv Synth Catal 2011. [DOI: 10.1002/adsc.201100371] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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33
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Ryšlavá H, Kalendová A, Doubnerová V, Skočdopol P, Kumar V, Kukačka Z, Pompach P, Vaněk O, Slámová K, Bojarová P, Kulik N, Ettrich R, Křen V, Bezouška K. Enzymatic characterization and molecular modeling of an evolutionarily interesting fungal β-N-acetylhexosaminidase. FEBS J 2011; 278:2469-84. [DOI: 10.1111/j.1742-4658.2011.08173.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Slámová K, Bojarová P, Petrásková L, Křen V. β-N-Acetylhexosaminidase: What's in a name…? Biotechnol Adv 2010; 28:682-93. [DOI: 10.1016/j.biotechadv.2010.04.004] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 04/17/2010] [Accepted: 04/24/2010] [Indexed: 01/28/2023]
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