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Kao MR, Ma TH, Chou HY, Chang SC, Cheng LC, Liao KS, Shie JJ, Harris PJ, Wong CH, Hsieh YSY. A Robust α-l-Fucosidase from Prevotella nigrescens for Glycoengineering Therapeutic Antibodies. ACS Chem Biol 2024. [PMID: 38912881 DOI: 10.1021/acschembio.4c00196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
Eliminating the core fucose from the N-glycans of the Fc antibody segment by pathway engineering or enzymatic methods has been shown to enhance the potency of therapeutic antibodies, especially in the context of antibody-dependent cytotoxicity (ADCC). However, there is a significant challenge due to the limited defucosylation efficiency of commercially available α-l-fucosidases. In this study, we report a unique α-l-fucosidase (PnfucA) from the bacterium Prevotella nigrescens that has a low sequence identity compared with all other known α-l-fucosidases and is highly reactive toward a core disaccharide substrate with fucose α(1,3)-, α (1,4)-and α(1,6)-linked to GlcNAc, and is less reactive toward the Fuc-α(1,2)-Gal on the terminal trisaccharide of the oligosaccharide Globo H (Bb3). The kinetic properties of the enzyme, such as its Km and kcat, were determined and the optimized expression of PnfucA gave a yield exceeding 30 mg/L. The recombinant enzyme retained its full activity even after being incubated for 6 h at 37 °C. Moreover, it retained 92 and 87% of its activity after freezing and freeze-drying treatments, respectively, for over 28 days. In a representative glycoengineering of adalimumab (Humira), PnfucA showed remarkable hydrolytic efficiency in cleaving the α(1,6)-linked core fucose from FucGlcNAc on the antibody with a quantitative yield. This enabled the seamless incorporation of biantennary sialylglycans by Endo-S2 D184 M in a one-pot fashion to yield adalimumab in a homogeneous afucosylated glycoform with an improved binding affinity toward Fcγ receptor IIIa.
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Affiliation(s)
- Mu-Rong Kao
- School of Pharmacy, College of Pharmacy, Taipei Medical University, No. 250 Wuxing Street, Taipei 11031, Taiwan
- Genomics Research Center, Academia Sinica, No. 128 Academia Road, Section 2, Nankang District, Taipei 115201, Taiwan
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm SE-10691, Sweden
| | - Tzu-Hsuan Ma
- School of Pharmacy, College of Pharmacy, Taipei Medical University, No. 250 Wuxing Street, Taipei 11031, Taiwan
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm SE-10691, Sweden
| | - Hsiang-Yu Chou
- School of Pharmacy, College of Pharmacy, Taipei Medical University, No. 250 Wuxing Street, Taipei 11031, Taiwan
| | - Shu-Chieh Chang
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm SE-10691, Sweden
| | - Lin-Chen Cheng
- School of Pharmacy, College of Pharmacy, Taipei Medical University, No. 250 Wuxing Street, Taipei 11031, Taiwan
| | - Kuo-Shiang Liao
- Genomics Research Center, Academia Sinica, No. 128 Academia Road, Section 2, Nankang District, Taipei 115201, Taiwan
| | - Jiun-Jie Shie
- Institute of Chemistry, Academia Sinica, No. 128 Academia Road, Section 2, Nankang District, Taipei 115201, Taiwan
| | - Philip J Harris
- School of Biological Sciences, The University of Auckland, Auckland Mail Centre, Private Bag 92019, Auckland 1142, New Zealand
| | - Chi-Huey Wong
- Genomics Research Center, Academia Sinica, No. 128 Academia Road, Section 2, Nankang District, Taipei 115201, Taiwan
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Yves S Y Hsieh
- School of Pharmacy, College of Pharmacy, Taipei Medical University, No. 250 Wuxing Street, Taipei 11031, Taiwan
- Genomics Research Center, Academia Sinica, No. 128 Academia Road, Section 2, Nankang District, Taipei 115201, Taiwan
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm SE-10691, Sweden
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2
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Martínez Gascueña A, Wu H, Wang R, Owen CD, Hernando PJ, Monaco S, Penner M, Xing K, Le Gall G, Gardner R, Ndeh D, Urbanowicz PA, Spencer DIR, Walsh M, Angulo J, Juge N. Exploring the sequence-function space of microbial fucosidases. Commun Chem 2024; 7:137. [PMID: 38890439 PMCID: PMC11189522 DOI: 10.1038/s42004-024-01212-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 05/28/2024] [Indexed: 06/20/2024] Open
Abstract
Microbial α-L-fucosidases catalyse the hydrolysis of terminal α-L-fucosidic linkages and can perform transglycosylation reactions. Based on sequence identity, α-L-fucosidases are classified in glycoside hydrolases (GHs) families of the carbohydrate-active enzyme database. Here we explored the sequence-function space of GH29 fucosidases. Based on sequence similarity network (SSN) analyses, 15 GH29 α-L-fucosidases were selected for functional characterisation. HPAEC-PAD and LC-FD-MS/MS analyses revealed substrate and linkage specificities for α1,2, α1,3, α1,4 and α1,6 linked fucosylated oligosaccharides and glycoconjugates, consistent with their SSN clustering. The structural basis for the substrate specificity of GH29 fucosidase from Bifidobacterium asteroides towards α1,6 linkages and FA2G2 N-glycan was determined by X-ray crystallography and STD NMR. The capacity of GH29 fucosidases to carry out transfucosylation reactions with GlcNAc and 3FN as acceptors was evaluated by TLC combined with ESI-MS and NMR. These experimental data supported the use of SSN to further explore the GH29 sequence-function space through machine-learning models. Our lightweight protein language models could accurately allocate test sequences in their respective SSN clusters and assign 34,258 non-redundant GH29 sequences into SSN clusters. It is expected that the combination of these computational approaches will be used in the future for the identification of novel GHs with desired specificities.
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Affiliation(s)
- Ana Martínez Gascueña
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Haiyang Wu
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
- GuangDong Engineering Technology Research Center of Enzyme and Biocatalysis, Institute of Biological and Medical Engineering, Guangdong Academy of Sciences, Guangzhou, China
| | - Rui Wang
- Beijing Key Lab of Traffic Data Analysis and Mining, Beijing Jiaotong University, Beijing, China
- Collaborative Innovation Center of Railway Traffic Safety, Beijing Jiaotong University, Beijing, China
- School of Computer and Information Technology, Beijing Jiaotong University, Beijing, China
| | - C David Owen
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, OX11 0FA, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, OX11 0FA, UK
| | - Pedro J Hernando
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
- Iceni Glycoscience Ltd., Norwich Research Park, Norwich, NR4 7JG, UK
| | - Serena Monaco
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Matthew Penner
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, OX11 0FA, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, OX11 0FA, UK
| | - Ke Xing
- School of Computer and Information Technology, Beijing Jiaotong University, Beijing, China
| | - Gwenaelle Le Gall
- Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | | | - Didier Ndeh
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
- University of Dundee, School of Life Sciences, Dundee, DD1 5EH, Scotland, UK
| | | | | | - Martin Walsh
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, OX11 0FA, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, OX11 0FA, UK
| | - Jesus Angulo
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
- Departamento de Química Orgánica, Universidad de Sevilla, 41012, Sevilla, Spain
- Instituto de Investigaciones Químicas (CSIC-US), 41092, Sevilla, Spain
| | - Nathalie Juge
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK.
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Tong Y, Lu X, Shen D, Rao L, Zou L, Lyu S, Hou L, Sun G, Chen L. Identification and characterization of emGalaseE, a β-1,4 galactosidase from Elizabethkingia meningoseptica, and its application on living cell surface. Int J Biol Macromol 2024; 268:131766. [PMID: 38657932 DOI: 10.1016/j.ijbiomac.2024.131766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 03/18/2024] [Accepted: 04/20/2024] [Indexed: 04/26/2024]
Abstract
The biological function of terminal galactose on glycoprotein is an open field of research. Although progress had being made on enzymes that can remove the terminal galactose on glycoproteins, there is a lack of report on galactosidases that can work directly on living cells. In this study, a unique beta 1,4 galactosidase was isolated from Elizabethkingia meningoseptica (Em). It exhibited favorable stability at various temperatures (4-37 °C) and pH (5-8) levels and can remove β-1, 4 linked galactoses directly from glycoproteins. Using Alanine scanning, we found that two acidic residues (Glu-468, and Glu-531) in the predicted active pocket are critical for galactosidase activity. In addition, we also demonstrated that it could cleave galactose residues present on living cell surface. As this enzyme has a potential application for living cell glycan editing, we named it emGalaseE or glycan-editing galactosidase I (csgeGalaseI). In summary, our findings lay the groundwork for further investigation by presenting a simple and effective approach for the removal of galactose moieties from cell surface.
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Affiliation(s)
- Yongliang Tong
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Xinrong Lu
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Danfeng Shen
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Lin Rao
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Lin Zou
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Shaoxian Lyu
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Linlin Hou
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, China.
| | - Guiqin Sun
- School of Medical Technology and Information Engineering, Zhejiang Chinese Medical University, Hangzhou 310053, Zhejiang Province, China.
| | - Li Chen
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China.
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Shen D, Lu X, Li W, Zou L, Tong Y, Wang L, Rao L, Zhang Y, Hou L, Sun G, Chen L. Identification and characterization of an α-1,3 mannosidase from Elizabethkingia meningoseptica and its potential attenuation impact on allergy associated with cross-reactive carbohydratedeterminant. Biochem Biophys Res Commun 2023; 672:17-26. [PMID: 37331167 DOI: 10.1016/j.bbrc.2023.06.035] [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: 05/28/2023] [Accepted: 06/10/2023] [Indexed: 06/20/2023]
Abstract
Core α-1,3 mannose is structurally near the core xylose and core fucose on core pentasaccharide from plant and insect glycoproteins. Mannosidase is a useful tool for characterization the role of core α-1,3 mannose in the composition of glycan related epitope, especially for those epitopes in which core xylose and core fucose are involved. Through functional genomic analysis, we identified a glycoprotein α-1,3 mannosidase and named it MA3. We used MA3 to treat allergen horseradish peroxidase (HRP) and phospholipase A2 (PLA2) separately. The results showed that after MA3 removed α-1,3 mannose on HRP, the reactivity of HRP with anti-core xylose polyclonal antibody almost disappeared. And the reactivity of MA3-treated PLA2 with anti-core fucose polyclonal antibody decreased partially. In addition, when PLA2 was conducted enzyme digestion by MA3, the reactivity between PLA2 and allergic patients' sera diminished. These results demonstrated that α-1,3 mannose was an critical component of glycan related epitope.
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Affiliation(s)
- Danfeng Shen
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Xinrong Lu
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Wenjie Li
- Clinical Laboratory, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang Province, China
| | - Lin Zou
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Yongliang Tong
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Lei Wang
- Department of Research and Development, SysDiagno Biomedtech, Nanjing, 211800, Jiangsu Province, China
| | - Lin Rao
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Yuxin Zhang
- School of Medical Technology and Information Engineering, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang Province, China
| | - Linlin Hou
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, 266109, Shandong Province, China.
| | - Guiqin Sun
- School of Medical Technology and Information Engineering, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang Province, China.
| | - Li Chen
- Dept. of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.
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Structure and function of microbial α-l-fucosidases: a mini review. Essays Biochem 2023; 67:399-414. [PMID: 36805644 PMCID: PMC10154630 DOI: 10.1042/ebc20220158] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/09/2023] [Accepted: 01/16/2023] [Indexed: 02/23/2023]
Abstract
Fucose is a monosaccharide commonly found in mammalian, insect, microbial and plant glycans. The removal of terminal α-l-fucosyl residues from oligosaccharides and glycoconjugates is catalysed by α-l-fucosidases. To date, glycoside hydrolases (GHs) with exo-fucosidase activity on α-l-fucosylated substrates (EC 3.2.1.51, EC 3.2.1.-) have been reported in the GH29, GH95, GH139, GH141 and GH151 families of the Carbohydrate Active Enzymes (CAZy) database. Microbes generally encode several fucosidases in their genomes, often from more than one GH family, reflecting the high diversity of naturally occuring fucosylated structures they encounter. Functionally characterised microbial α-l-fucosidases have been shown to act on a range of substrates with α-1,2, α-1,3, α-1,4 or α-1,6 fucosylated linkages depending on the GH family and microorganism. Fucosidases show a modular organisation with catalytic domains of GH29 and GH151 displaying a (β/α)8-barrel fold while GH95 and GH141 show a (α/α)6 barrel and parallel β-helix fold, respectively. A number of crystal structures have been solved in complex with ligands, providing structural basis for their substrate specificity. Fucosidases can also be used in transglycosylation reactions to synthesise oligosaccharides. This mini review provides an overview of the enzymatic and structural properties of microbial α-l-fucosidases and some insights into their biological function and biotechnological applications.
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Characterization and stabilization of the α-L-fucosidase set from Lacticaseibacillus rhamnosus INIA P603. Appl Microbiol Biotechnol 2022; 106:8067-8077. [PMID: 36370158 DOI: 10.1007/s00253-022-12262-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/20/2022] [Accepted: 10/23/2022] [Indexed: 11/13/2022]
Abstract
This study describes the molecular identification, biochemical characterization, and stabilization of three recombinant AlfA, AlfB, and AlfC fucosidases from Lacticaseibacillus rhamnosus INIA P603. Even though previous studies revealed the presence of fucosidase activity in L. rhamnosus extracts, the identification of the fucosidases, their physicochemical properties, and the substrate spectrum remained unknown. Although the presence of alfB is not common in strains of L. rhamnosus, fucosidases from L. rhamnosus INIA P603 were selected because this strain exhibited higher fucosidase activity in culture and the complete set of fucosidases. A high yield of purified recombinant AlfA, AlfB, and AlfC fucosidases was obtained (8, 12, and 18 mg, respectively). AlfA, AlfB, and AlfC showed their optimal activities at pH 5.0 and 4.0 at 60 °C, 40 °C, and 50 °C, respectively. Unlike 3-fucosyllactose, all three recombinant fucosidases were able to hydrolyze 2'-fucosyllactose (2'-FL), and their activities were improved through their immobilization on agarose supports. Nevertheless, immobilized AlfB exhibited the highest hydrolysis, releasing 39.6 µmol of fucose mg enzyme-1 min-1. Only the immobilized AlfB was able to synthetize 2'-FL. In conclusion, the enzymatic properties elucidated in this study support the potential ability of fucosidases from L. rhamnosus INIA P603 to hydrolyze fucosylated substrates as well as justifying interest for further research into AlfB for its application to catalyze the synthesis of fucosylated prebiotics. KEY POINTS: • Few strains of L. rhamnosus exhibited alfB on their chromosomes. • Fucosidases from L. rhamnosus INIA P603 were characterized and stabilized. • Although all the fucosidases hydrolyzed 2'-FL, only AlfB transfucosylated lactose.
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Nuccio EE, Blazewicz SJ, Lafler M, Campbell AN, Kakouridis A, Kimbrel JA, Wollard J, Vyshenska D, Riley R, Tomatsu A, Hestrin R, Malmstrom RR, Firestone M, Pett-Ridge J. HT-SIP: a semi-automated stable isotope probing pipeline identifies cross-kingdom interactions in the hyphosphere of arbuscular mycorrhizal fungi. MICROBIOME 2022; 10:199. [PMID: 36434737 PMCID: PMC9700909 DOI: 10.1186/s40168-022-01391-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Linking the identity of wild microbes with their ecophysiological traits and environmental functions is a key ambition for microbial ecologists. Of many techniques that strive for this goal, Stable-isotope probing-SIP-remains among the most comprehensive for studying whole microbial communities in situ. In DNA-SIP, actively growing microorganisms that take up an isotopically heavy substrate build heavier DNA, which can be partitioned by density into multiple fractions and sequenced. However, SIP is relatively low throughput and requires significant hands-on labor. We designed and tested a semi-automated, high-throughput SIP (HT-SIP) pipeline to support well-replicated, temporally resolved amplicon and metagenomics experiments. We applied this pipeline to a soil microhabitat with significant ecological importance-the hyphosphere zone surrounding arbuscular mycorrhizal fungal (AMF) hyphae. AMF form symbiotic relationships with most plant species and play key roles in terrestrial nutrient and carbon cycling. RESULTS Our HT-SIP pipeline for fractionation, cleanup, and nucleic acid quantification of density gradients requires one-sixth of the hands-on labor compared to manual SIP and allows 16 samples to be processed simultaneously. Automated density fractionation increased the reproducibility of SIP gradients compared to manual fractionation, and we show adding a non-ionic detergent to the gradient buffer improved SIP DNA recovery. We applied HT-SIP to 13C-AMF hyphosphere DNA from a 13CO2 plant labeling study and created metagenome-assembled genomes (MAGs) using high-resolution SIP metagenomics (14 metagenomes per gradient). SIP confirmed the AMF Rhizophagus intraradices and associated MAGs were highly enriched (10-33 atom% 13C), even though the soils' overall enrichment was low (1.8 atom% 13C). We assembled 212 13C-hyphosphere MAGs; the hyphosphere taxa that assimilated the most AMF-derived 13C were from the phyla Myxococcota, Fibrobacterota, Verrucomicrobiota, and the ammonia-oxidizing archaeon genus Nitrososphaera. CONCLUSIONS Our semi-automated HT-SIP approach decreases operator time and improves reproducibility by targeting the most labor-intensive steps of SIP-fraction collection and cleanup. We illustrate this approach in a unique and understudied soil microhabitat-generating MAGs of actively growing microbes living in the AMF hyphosphere (without plant roots). The MAGs' phylogenetic composition and gene content suggest predation, decomposition, and ammonia oxidation may be key processes in hyphosphere nutrient cycling. Video Abstract.
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Affiliation(s)
- Erin E. Nuccio
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Steven J. Blazewicz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Marissa Lafler
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Ashley N. Campbell
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Anne Kakouridis
- Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
- Department of Environmental Science Policy and Management, University of California, Berkeley, CA USA
| | - Jeffrey A. Kimbrel
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Jessica Wollard
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | | | | | | | - Rachel Hestrin
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA USA
| | | | - Mary Firestone
- Department of Environmental Science Policy and Management, University of California, Berkeley, CA USA
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
- Life & Environmental Sciences Department, University of California Merced, Merced, CA USA
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Abstract
N-glycans are common posttranslational modifications on plant proteins, particularly secreted proteins. As plants are the major component of the human diet, and especially in high-fiber diets, plant N-glycans are prominent in the gut. Despite their ubiquity in the gut, the degradation of plant N-glycans by the microbiota has not been described. Here we used a functional analysis approach, coupled to detailed biochemistry and structural biology, to reveal a pathway for the degradation of plant N-glycans encoded by the human gut microbiota. The work reveals insight into how our gut microbes use plant N-glycans as a nutrient source and also provides tools to modify plant N-glycans to mitigate allergic responses, either from foods or plant-expressed therapeutics. The major nutrients available to the human colonic microbiota are complex glycans derived from the diet. To degrade this highly variable mix of sugar structures, gut microbes have acquired a huge array of different carbohydrate-active enzymes (CAZymes), predominantly glycoside hydrolases, many of which have specificities that can be exploited for a range of different applications. Plant N-glycans are prevalent on proteins produced by plants and thus components of the diet, but the breakdown of these complex molecules by the gut microbiota has not been explored. Plant N-glycans are also well characterized allergens in pollen and some plant-based foods, and when plants are used in heterologous protein production for medical applications, the N-glycans present can pose a risk to therapeutic function and stability. Here we use a novel genome association approach for enzyme discovery to identify a breakdown pathway for plant complex N-glycans encoded by a gut Bacteroides species and biochemically characterize five CAZymes involved, including structures of the PNGase and GH92 α-mannosidase. These enzymes provide a toolbox for the modification of plant N-glycans for a range of potential applications. Furthermore, the keystone PNGase also has activity against insect-type N-glycans, which we discuss from the perspective of insects as a nutrient source.
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Li J, He Z, Liang Y, Peng T, Hu Z. Insights into Algal Polysaccharides: A Review of Their Structure, Depolymerases, and Metabolic Pathways. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:1749-1765. [PMID: 35124966 DOI: 10.1021/acs.jafc.1c05365] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In recent years, marine macroalgae with extensive biomass have attracted the attention of researchers worldwide. Furthermore, algal polysaccharides have been widely studied in the food, pharmaceutical, and cosmetic fields because of their various kinds of bioactivities. However, there are immense barriers to their application as a result of their high molecular size, poor solubility, hydrocolloid nature, and low physiological activities. Unique polysaccharides, such as laminarin, alginate, fucoidan, agar, carrageenan, porphyran, ulvan, and other complex structural polysaccharides, can be digested by marine bacteria with many carbohydrate-active enzymes (CAZymes) by breaking down the limitation of glycosidic bonds. However, structural elucidation of algal polysaccharides, metabolic pathways, and identification of potential polysaccharide hydrolases that participate in different metabolic pathways remain major obstacles restricting the efficient utilization of algal oligosaccharides. This review focuses on the structure, hydrolase families, metabolic pathways, and potential applications of seven macroalgae polysaccharides. These results will contribute to progressing our understanding of the structure of algal polysaccharides and their metabolic pathways and will be valuable for clearing the way for the compelling utilization of bioactive oligosaccharides.
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Affiliation(s)
- Jin Li
- Department of Biology, College of Science, Shantou University, Shantou, Guangdong 515063, People's Republic of China
| | - Zhixiao He
- Department of Biology, College of Science, Shantou University, Shantou, Guangdong 515063, People's Republic of China
| | - Yumei Liang
- Department of Biology, College of Science, Shantou University, Shantou, Guangdong 515063, People's Republic of China
| | - Tao Peng
- Department of Biology, College of Science, Shantou University, Shantou, Guangdong 515063, People's Republic of China
| | - Zhong Hu
- Department of Biology, College of Science, Shantou University, Shantou, Guangdong 515063, People's Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, Guangdong 511458, People's Republic of China
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10
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OUP accepted manuscript. Glycobiology 2022; 32:529-539. [DOI: 10.1093/glycob/cwab132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 12/09/2021] [Accepted: 12/17/2021] [Indexed: 11/14/2022] Open
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11
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Klontz EH, Li C, Kihn K, Fields JK, Beckett D, Snyder GA, Wintrode PL, Deredge D, Wang LX, Sundberg EJ. Structure and dynamics of an α-fucosidase reveal a mechanism for highly efficient IgG transfucosylation. Nat Commun 2020; 11:6204. [PMID: 33277506 PMCID: PMC7718225 DOI: 10.1038/s41467-020-20044-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/15/2020] [Indexed: 11/26/2022] Open
Abstract
Fucosylation is important for the function of many proteins with biotechnical and medical applications. Alpha-fucosidases comprise a large enzyme family that recognizes fucosylated substrates with diverse α-linkages on these proteins. Lactobacillus casei produces an α-fucosidase, called AlfC, with specificity towards α(1,6)-fucose, the only linkage found in human N-glycan core fucosylation. AlfC and certain point mutants thereof have been used to add and remove fucose from monoclonal antibody N-glycans, with significant impacts on their effector functions. Despite the potential uses for AlfC, little is known about its mechanism. Here, we present crystal structures of AlfC, combined with mutational and kinetic analyses, hydrogen–deuterium exchange mass spectrometry, molecular dynamic simulations, and transfucosylation experiments to define the molecular mechanisms of the activities of AlfC and its transfucosidase mutants. Our results indicate that AlfC creates an aromatic subsite adjacent to the active site that specifically accommodates GlcNAc in α(1,6)-linkages, suggest that enzymatic activity is controlled by distinct open and closed conformations of an active-site loop, with certain mutations shifting the equilibrium towards open conformations to promote transfucosylation over hydrolysis, and provide a potentially generalizable framework for the rational creation of AlfC transfucosidase mutants. AlfC transfucosidase is used to modulate fucosylation of glycans decorating monoclonal antibodies. Herein, structural and biophysical characterization reveals the enzymatic mechanism of AlfC and a blueprint for the design of AlfC mutants with novel specificities and functions.
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Affiliation(s)
- Erik H Klontz
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Program in Molecular Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Chao Li
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA
| | - Kyle Kihn
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, College Park, MD, 21201, USA
| | - James K Fields
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Program in Molecular Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Dorothy Beckett
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA
| | - Greg A Snyder
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Patrick L Wintrode
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, College Park, MD, 21201, USA
| | - Daniel Deredge
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, College Park, MD, 21201, USA
| | - Lai-Xi Wang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA
| | - Eric J Sundberg
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA.
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12
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Nakamura S, Miyazaki T, Park EY. α-L-Fucosidase from Bombyx mori has broad substrate specificity and hydrolyzes core fucosylated N-glycans. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 124:103427. [PMID: 32561391 DOI: 10.1016/j.ibmb.2020.103427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/25/2020] [Accepted: 05/31/2020] [Indexed: 06/11/2023]
Abstract
N-glycans play a role in physiological functions, including glycoprotein conformation, signal transduction, and antigenicity. Insects display both α-1,6- and α-1,3-linked fucose residues bound to the innermost N-acetylglucosamine of N-glycans whereas core α-1,3-fucosylated N-glycans are not found in mammals. Functions of insect core-fucosylated glycans are not clear, and no α-L-fucosidase related to the N-glycan degradation has been identified. In the genome of the domestic silkworm, Bombyx mori, a gene for a protein, BmFucA, belonging to the glycoside hydrolase family 29 is a candidate for an α-L-fucosidase gene. In this study, BmFucA was cloned and recombinantly expressed as a glutathione-S-transferase tagged protein (GST-BmFucA). Recombinant GST-BmFucA exhibited broad substrate specificity and hydrolyzed p-nitrophenyl α-L-fucopyranoside, 2'-fucosyllactose, 3-fucosyllactose, 3-fucosyl-N,N'-diacetylchitobiose, and 6-fucosyl-N,N'-diacetylchitobiose. Further, GST-BmFucA released fucose from both pyridylaminated complex-type and paucimannose-type glycans that were core-α-1,6-fucosylated. GST-BmFucA also shows hydrolysis activity for core-fucosylated glycans attached to phospholipase A2 from bee venom. BmFucA may be involved in the catabolism of core-fucosylated N-glycans in B. mori.
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Affiliation(s)
- Shuntaro Nakamura
- Department of Agriculture, Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Takatsugu Miyazaki
- Department of Agriculture, Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan; Green Chemistry Research Division, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan.
| | - Enoch Y Park
- Department of Agriculture, Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan; Green Chemistry Research Division, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
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13
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Liu P, Zhang H, Wang Y, Chen X, Jin L, Xu L, Xiao M. Screening and characterization of an α-L-fucosidase from Bacteroides fragilis NCTC9343 for synthesis of fucosyl-N-acetylglucosamine disaccharides. Appl Microbiol Biotechnol 2020; 104:7827-7840. [PMID: 32715363 DOI: 10.1007/s00253-020-10759-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 06/18/2020] [Accepted: 06/29/2020] [Indexed: 11/30/2022]
Abstract
Fucosyl-N-acetylglucosamine disaccharides are present in many biologically important oligosaccharides, such as human milk oligosaccharides, Lewis carbohydrate antigens, and glycans on cell-surface glycoconjugate receptors, and thus have vast potential for infant formulas, prebiotics, and pharmaceutical applications. In this work, in order to screen biocatalysts for enzymatic synthesis of fucosyl-N-acetylglucosamine disaccharides, we performed sequence analysis of 12 putative and one known α-L-fucosidases of Bacteroides fragilis NCTC9343 and constructed a phylogenetic tree of the nine GH29 α-L-fucosidases. After that, five GH29A α-L-fucosidases were cloned, and four of them were successfully heterogeneous expressed and screened for transglycosylation activity, and a GH29A α-L-fucosidase (BF3242) that synthesized a mix of Fuc-α-1,3/1,6-GlcNAc disaccharides using pNPαFuc as donor and GlcNAc as acceptor was characterized. The effects of initial substrate concentration, pH, temperature, and reaction time on its transglycosylation activity were studied in detail. Under the optimum conditions of 0.05 U/mL enzyme, 20 mM pNPαFuc, and 500 mM GlcNAc in sodium buffer (pH 7.5) at 37 °C for 45 min, BF3242 efficiently synthesized Fuc-α-1,3/1,6-GlcNAc at a maximum yield of 79.0% with the ratio of 0.48 for 1,3/1,6. The molecular dynamics simulation analysis revealed that Loop-4 (His220-Ser245) in the putative 3D model of BF3242 displayed significant changes throughout the thermal simulations, might being responsible for the changes in the ratio of two regioisomeric products at different temperatures. This work provided not only a potential synthetic tool for enzymatic synthesis of fucosyl-N-acetylglucosamine disaccharides but also a possibility for the formation of regioisomeric products in glycosidase-catalyzed transglycosylation. KEY POINTS: • Sequence analysis of α-L-fucosidases of Bacteroides fragilis NCTC9343 • Obtainment of an α-L-fucosidase with high transglycosylation activity • Explanation why temperature affected the ratio of two regioisomeric products.
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Affiliation(s)
- Peng Liu
- 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
| | - Huaqin Zhang
- 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
| | - Yuying Wang
- 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
| | - 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.,Department of Clinical Laboratory Medicine, Jinan Maternity and Child Care Hospital Affiliated to Shandong First Medical University, Jinan, 250001, 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
| | - 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.
| | - 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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14
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Novel NGLY1 gene variants in Chinese children with global developmental delay, microcephaly, hypotonia, hypertransaminasemia, alacrimia, and feeding difficulty. J Hum Genet 2020; 65:387-396. [PMID: 31965062 DOI: 10.1038/s10038-019-0719-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 12/18/2019] [Accepted: 12/22/2019] [Indexed: 11/09/2022]
Abstract
NGLY1 deficiency is the first and only autosomal recessive congenital disorder of N-linked deglycosylation (NGLY1-CDDG). To date, no patients with NGLY1 deficiency has been reported from mainland China or East Asia in English literature. Here, we present six patients with a diagnosis of NGLY1-CDDG on the basis of clinical phenotype, genetic testing, and functional studies. We retrospectively analyzed clinical phenotypes and NGLY1 genotypes of six cases from four families. Informed consent was obtained for diagnosis and treatment. In-silico tools and in vitro enzyme activity assays were used to determine pathogenicity of NGLY1 varaints. All patients had typical features of NGLY1-CDDG, including global developmental delay, microcephaly, hypotonia, hypertransaminasemia, alacrimia, and feeding difficulty. Dysmorphic features found in our patients include flat nasal bridge, loose and hollow cheeks, short stature, malnutrition, and ptosis. Pachylosis could be a novel cutaneous feature that may be explained by lack of sweat. We found three novel variants, including one missense (c.982C > G/p.Arg328Gly), one splice site (c.1003+3A > G), and one frame-shift (c.1637-1652delCATCTTTTGCTTATAT/p.Ser546PhefsTer) variant. All mutations were predicted to be disease causing with in-silico prediction tools, and affected at least one feature of gene splicing. Protein modeling showed missense variants may affect covalent bonding within the protein structure, or interrupt active/binding amino-acid residues. In vitro studies indicated that proteins carrying missense variants (p.Arg328Gly and p.Tyr342Cys) lost the enzyme activity. We expanded clinical phenotype and genetic mutation spectrum of NGLY1-CDDG by reporting six cases, three novel variants, and novel clinical features from mainland China.
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15
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Filamentation initiated by Cas2 and its association with the acquisition process in cells. Int J Oral Sci 2019; 11:29. [PMID: 31578319 PMCID: PMC6802651 DOI: 10.1038/s41368-019-0063-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/18/2019] [Accepted: 07/07/2019] [Indexed: 12/15/2022] Open
Abstract
Cas1-and-Cas2-mediated new spacer acquisition is an essential process for bacterial adaptive immunity. The process is critical for the ecology of the oral microflora and oral health. Although molecular mechanisms for spacer acquisition are known, it has never been established if this process is associated with the morphological changes of bacteria. In this study, we demonstrated a novel Cas2-induced filamentation phenotype in E. coli that was regulated by co-expression of the Cas1 protein. A 30 amino acid motif at the carboxyl terminus of Cas2 is necessary for this function. By imaging analysis, we provided evidence to argue that Cas-induced filamentation is a step coupled with new spacer acquisition during which filaments are characterised by polyploidy with asymmetric cell division. This work may open new opportunities to investigate the adaptive immune response and microbial balance for oral health.
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16
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You J, Lin S, Jiang T. Origins and Evolution of the α-L-Fucosidases: From Bacteria to Metazoans. Front Microbiol 2019; 10:1756. [PMID: 31507539 PMCID: PMC6718869 DOI: 10.3389/fmicb.2019.01756] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/16/2019] [Indexed: 12/24/2022] Open
Abstract
α-L-fucosidases (EC 3.2.1.51, FUC), belonging to the glycoside hydrolase family 29 (GH29), play important roles in several biological processes and are markers used for detecting hepatocellular carcinoma. In this study, a protein sequence similarity network (SSN) was generated and a subsequent evolutionary analysis was performed to understand the enzymes comprehensively. The SSN indicated that the proteins in the FUC family are mainly present in bacteria, fungi, metazoans, plants, as well as in archaea, but less abundantly. The sequences in bacteria were found to be more diverse than those in other taxonomic groups. The SSN and a phylogenetic tree both supported that the proteins in the FUC family can be classified into 3 subfamilies. FUCs in each subfamily are under the pressure of negative selection. The enzymes from metazoans, fungi, and plants separated into the three subfamilies and shared high similarity with the bacterial homologs. The multiple sequence alignment results indicated that the amino acid residues for binding α-L-fucosidase and catalysis are highly conserved in the 3 subfamilies; however, the evolutionary patterns were different, based on the coevolution analysis in the subfamily of metazoans and bacteria. Finally, gene duplication plays an important role for α-L-fucosidase evolution, not only in metazoans, but also in bacteria and fungi.
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Affiliation(s)
- Jia You
- Department of Hepatology, The Liver Center, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Shujin Lin
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, China
| | - Tao Jiang
- Department of Urology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
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17
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Identification and characterization of a novel glycoprotein core xylosidase from the bacterium Elizabethkingia meningoseptica. Biochem Biophys Res Commun 2019; 517:390-397. [PMID: 31358319 DOI: 10.1016/j.bbrc.2019.07.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 07/11/2019] [Indexed: 11/24/2022]
Abstract
Although core xylose on glycoproteins has been implicated in allergy, infection and other biological processes, research on core xylose modification is rare. The lack of a β-d-xylosidase that can catalytically remove the core xylose directly from glycoproteins is a reason for this. Through functional genomic analysis, we identified a glycoprotein core xylosidase and named it gpcXase I. gpcXase I is located immediately downstream of glycoprotein core fucosidase cFase I in Elizabethkingia meningoseptica. These two genes form a functional operon for glycoprotein core modifications. Three acidic residues (Asp-200, Asp-304 and Glu-649) were identified as key catalytic sites for gpcXase I activity, suggesting a unique triacdic mechanize for its activity. Asp-200 was identified a novel and essential base catalysts in the catalytic process, Asp-304 and Glu-649 was function as catalytic nucleophiles and acid catalysts, respectively. In addition, IgE-specific reactions were detected in 55% of serum samples collected from 40 allergic patients, and the reactions were significantly attenuated by removal of the core xylose of the allergen by treatment with gpcXase I. gpcXase I is a novel tool for basic and clinical glycomics.
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