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Li S, Chen M, Wang Z, Abudourexiti W, Zhang L, Ding C, Ding L, Gong J. Ant may well destroy a whole dam: glycans of colonic mucus barrier disintegrated by gut bacteria. Microbiol Res 2024; 281:127599. [PMID: 38219635 DOI: 10.1016/j.micres.2023.127599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 12/29/2023] [Accepted: 12/30/2023] [Indexed: 01/16/2024]
Abstract
The colonic mucus layer plays a critical role in maintaining the integrity of the colonic mucosal barrier, serving as the primary defense against colonic microorganisms. Predominantly composed of mucin 2 (MUC2), a glycosylation-rich protein, the mucus layer forms a gel-like coating that covers the colonic epithelium surface. This layer provides a habitat for intestinal microorganisms, which can utilize mucin glycans present in the mucus layer as a sustainable source of nutrients. Additionally, metabolites produced by the microbiota during the metabolism of mucus glycans have a profound impact on host health. Under normal conditions, the production and consumption of mucus maintain a dynamic balance. However, several studies have demonstrated that certain factors, such as dietary fiber deficiency, can enhance the metabolism of mucus glycans by gut bacteria, thereby disturbing this balance and weakening the mucus barrier function of the mucus layer. To better understand the occurrence and development of colon-related diseases, it is crucial to investigate the complex metabolic patterns of mucus glycosylation by intestinal microorganisms. Our objective was to comprehensively review these patterns in order to clarify the effects of mucus layer glycan metabolism by intestinal microorganisms on the host.
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Affiliation(s)
- Song Li
- Department of General Surgery, Affiliated Jinling Hospital, Medical School, Nanjing University, Nanjing, China
| | - Mingfei Chen
- Department of General Surgery, Affiliated Jinling Hospital, Medical School, Nanjing University, Nanjing, China
| | - Zhongyuan Wang
- Department of General Surgery, Affiliated Jinling Hospital, Medical School, Nanjing University, Nanjing, China
| | - Waresi Abudourexiti
- Department of General Surgery, Affiliated Jinling Hospital, Medical School, Nanjing University, Nanjing, China
| | - Liang Zhang
- Department of Gastrointestinal Surgery, Xuzhou Central Hospital, Xuzhou Clinical School of Xuzhou Medical College, Jiangsu, China
| | - Chao Ding
- Department of General Surgery, Affiliated Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China.
| | - Lin Ding
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China; Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China.
| | - Jianfeng Gong
- Department of General Surgery, Affiliated Jinling Hospital, Medical School, Nanjing University, Nanjing, China.
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González D, Morales-Olavarria M, Vidal-Veuthey B, Cárdenas JP. Insights into early evolutionary adaptations of the Akkermansia genus to the vertebrate gut. Front Microbiol 2023; 14:1238580. [PMID: 37779688 PMCID: PMC10540074 DOI: 10.3389/fmicb.2023.1238580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/21/2023] [Indexed: 10/03/2023] Open
Abstract
Akkermansia, a relevant mucin degrader from the vertebrate gut microbiota, is a member of the deeply branched Verrucomicrobiota, as well as the only known member of this phylum to be described as inhabitants of the gut. Only a few Akkermansia species have been officially described so far, although there is genomic evidence addressing the existence of more species-level variants for this genus. This niche specialization makes Akkermansia an interesting model for studying the evolution of microorganisms to their adaptation to the gastrointestinal tract environment, including which kind of functions were gained when the Akkermansia genus originated or how the evolutionary pressure functions over those genes. In order to gain more insight into Akkermansia adaptations to the gastrointestinal tract niche, we performed a phylogenomic analysis of 367 high-quality Akkermansia isolates and metagenome-assembled genomes, in addition to other members of Verrucomicrobiota. This work was focused on three aspects: the definition of Akkermansia genomic species clusters and the calculation and functional characterization of the pangenome for the most represented species; the evolutionary relationship between Akkermansia and their closest relatives from Verrucomicrobiota, defining the gene families which were gained or lost during the emergence of the last Akkermansia common ancestor (LAkkCA) and; the evaluation of the evolutionary pressure metrics for each relevant gene family of main Akkermansia species. This analysis found 25 Akkermansia genomic species clusters distributed in two main clades, divergent from their non-Akkermansia relatives. Pangenome analyses suggest that Akkermansia species have open pangenomes, and the gene gain/loss model indicates that genes associated with mucin degradation (both glycoside hydrolases and peptidases), (micro)aerobic metabolism, surface interaction, and adhesion were part of LAkkCA. Specifically, mucin degradation is a very ancestral innovation involved in the origin of Akkermansia. Horizontal gene transfer detection suggests that Akkermansia could receive genes mostly from unknown sources or from other Gram-negative gut bacteria. Evolutionary metrics suggest that Akkemansia species evolved differently, and even some conserved genes suffered different evolutionary pressures among clades. These results suggest a complex evolutionary landscape of the genus and indicate that mucin degradation could be an essential feature in Akkermansia evolution as a symbiotic species.
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Affiliation(s)
- Dámariz González
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago, Chile
| | - Mauricio Morales-Olavarria
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago, Chile
| | - Boris Vidal-Veuthey
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago, Chile
| | - Juan P. Cárdenas
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago, Chile
- Escuela de Biotecnología, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago, Chile
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Davey LE, Malkus PN, Villa M, Dolat L, Holmes ZC, Letourneau J, Ansaldo E, David LA, Barton GM, Valdivia RH. A genetic system for Akkermansia muciniphila reveals a role for mucin foraging in gut colonization and host sterol biosynthesis gene expression. Nat Microbiol 2023; 8:1450-1467. [PMID: 37337046 DOI: 10.1038/s41564-023-01407-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/10/2023] [Indexed: 06/21/2023]
Abstract
Akkermansia muciniphila, a mucophilic member of the gut microbiota, protects its host against metabolic disorders. Because it is genetically intractable, the mechanisms underlying mucin metabolism, gut colonization and its impact on host physiology are not well understood. Here we developed and applied transposon mutagenesis to identify genes important for intestinal colonization and for the use of mucin. An analysis of transposon mutants indicated that de novo biosynthesis of amino acids was required for A. muciniphila growth on mucin medium and that many glycoside hydrolases are redundant. We observed that mucin degradation products accumulate in internal compartments within bacteria in a process that requires genes encoding pili and a periplasmic protein complex, which we term mucin utilization locus (MUL) genes. We determined that MUL genes were required for intestinal colonization in mice but only when competing with other microbes. In germ-free mice, MUL genes were required for A. muciniphila to repress genes important for cholesterol biosynthesis in the colon. Our genetic system for A. muciniphila provides an important tool with which to uncover molecular links between the metabolism of mucins, regulation of lipid homeostasis and potential probiotic activities.
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Affiliation(s)
- Lauren E Davey
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA.
- Duke Microbiome Center, Duke University, Durham, NC, USA.
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada.
| | - Per N Malkus
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Max Villa
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Lee Dolat
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Zachary C Holmes
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Jeff Letourneau
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Eduard Ansaldo
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Lawrence A David
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Gregory M Barton
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Raphael H Valdivia
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA.
- Duke Microbiome Center, Duke University, Durham, NC, USA.
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Mucin utilization by gut microbiota: recent advances on characterization of key enzymes. Essays Biochem 2023; 67:345-353. [PMID: 36695502 PMCID: PMC10154618 DOI: 10.1042/ebc20220121] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/04/2023] [Accepted: 01/09/2023] [Indexed: 01/26/2023]
Abstract
The gut microbiota interacts with the host through the mucus that covers and protects the gastrointestinal epithelium. The main component of the mucus are mucins, glycoproteins decorated with hundreds of different O-glycans. Some microbiota members can utilize mucin O-glycans as carbons source. To degrade these host glycans the bacteria express multiple carbohydrate-active enzymes (CAZymes) such as glycoside hydrolases, sulfatases and esterases which are active on specific linkages. The studies of these enzymes in an in vivo context have started to reveal their importance in mucin utilization and gut colonization. It is now clear that bacteria evolved multiple specific CAZymes to overcome the diversity of linkages found in O-glycans. Additionally, changes in mucin degradation by gut microbiota have been associated with diseases like obesity, diabetes, irritable bowel disease and colorectal cancer. Thereby understanding how CAZymes from different bacteria work to degrade mucins is of critical importance to develop new treatments and diagnostics for these increasingly prevalent health problems. This mini-review covers the recent advances in biochemical characterization of mucin O-glycan-degrading CAZymes and how they are connected to human health.
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Li CC, Yi H, Wang YM, Tang XY, Zhu YB, Song YJ, Zhao NL, Huang Q, Mou XY, Luo GH, Liu TG, Yang GL, Zeng YJ, Wang LJ, Tang H, Fan G, Bao R. Nucleotide binding as an allosteric regulatory mechanism for Akkermansia muciniphila β- N-acetylhexosaminidase Am2136. Gut Microbes 2022; 14:2143221. [PMID: 36394293 PMCID: PMC9673926 DOI: 10.1080/19490976.2022.2143221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
β-N-acetylhexosaminidases (EC3.2.1.52), which belong to the glycosyl hydrolase family GH20, are important enzymes for oligosaccharides modification. Numerous microbial β-N-acetylhexosaminidases have been investigated for applications in biology, biomedicine and biotechnology. Akkermansia muciniphila is an anaerobic intestinal commensal bacterium which possesses specific β-N-acetylhexosaminidases for gut mucosal layer colonization and mucin degradation. In this study, we assessed the in vitro mucin glycan cleavage activity of the A. muciniphila β-N-acetylhexosaminidase Am2136 and demonstrated its ability that hydrolyzing the β-linkages joining N-acetylglucosamine to a wide variety of aglycone residues, which indicated that Am2136 may be a generalist β-N-acetylhexosaminidase. Structural and enzyme activity assay experiments allowed us to probe the essential function of the inter-domain interactions in β23-β33. Importantly, we revealed that the hydrolysis activity of Am2136 was enhanced by nucleotides. We further speculated that this activation mechanism might be associated with the conformational motions between domain III and IV. To our knowledge, this is the first report of nucleotide effector regulated β-N-acetylhexosaminidase, to reveal its novel biological functions. These findings contribute to understanding the distinct properties within the GH20 family and lay a certain foundation to develop controllable glycan hydrolyzing catalysts.Abbreviations: OD600 - optical cell densities at 600 nm; LB - Luria-Bertani; IPTG - isopropyl β-D-1-thiogalactopyranoside; PMSF - phenylmethanesulfonyl fluoride; rmsd - root mean square deviation; GlcNAc - N-acetyl-β-D-glucosamine; GalNAc - N-acetyl-β-D-galactosamine; Gal - galactose.
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Affiliation(s)
- Chang-Cheng Li
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Huan Yi
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yan-Mei Wang
- Institute of traditional Chinese medicine, Sichuan College of traditional Chinese Medicine (Sichuan Second Hospital of TCM), Chengdu, China
| | - Xin-Yue Tang
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Yi-Bo Zhu
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Ying-Jie Song
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Ning-Lin Zhao
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Qin Huang
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Xing-Yu Mou
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Gui-Hua Luo
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Tong-Gen Liu
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Gang-Long Yang
- School of Biotechnology, Jiangnan University, Chengdu, China
| | - Yu-Jiao Zeng
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Li-Jie Wang
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Hong Tang
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China,Hong Tang Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University. Chengdu. China
| | - Gang Fan
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China,Gang Fan State Key Laboratory of Southwestern Chinese Medicine Resources, College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine. Chengdu. China
| | - Rui Bao
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China,CONTACT Rui Bao
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Qian K, Chen S, Wang J, Sheng K, Wang Y, Zhang M. A β- N-acetylhexosaminidase Amuc_2109 from Akkermansia muciniphila protects against dextran sulfate sodium-induced colitis in mice by enhancing intestinal barrier and modulating gut microbiota. Food Funct 2022; 13:2216-2227. [PMID: 35133390 DOI: 10.1039/d1fo04094d] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inflammatory bowel disease (IBD) is associated with the microbial composition of the gut and its metabolites. Akkermansia muciniphila is a probiotic that exerts a significant alleviative or therapeutic effect on host enteritis. This study was designed to determine the protective effect and potential mechanism underlying the secretion of β-acetylaminohexosidase (Amuc_2109) by A. muciniphila against dextran sulfate sodium (DSS)-induced colitis in mice. C57BL/6 mice were gavaged with Amuc_2109 for 21 days, and during the last seven days of treatment, they drank DSS dissolved in their drinking water to induce colitis. Our results showed that supplementation with Amuc_2109 improved DSS-induced colitis as evidenced by lowered disease activity index (DAI) scores, reduced weight loss, increased colon length, and inhibited oxidative stress. In addition, Amuc_2109 inhibited the overexpression of inflammatory cytokines (TNF-α, IL-1β, IL-6) and the NLR family pyrin domain containing 3 (NLRP3) inflammasome in DSS-induced colitis. Furthermore, supplementation with Amuc_2109 also restored the mRNA expression of tight junction proteins (ZO-1, occludin, claudin-1). Further analysis of fecal microbial 16S rRNA sequences showed that Amuc_2109 reshaped the intestinal microbiota. While the anti-inflammatory effects of Amuc_2109 were only manifested with the wild-type protein, the anti-inflammatory effects were completely lost after the mutation of its key catalytic amino acids rendered Amuc_2109 inactive. In summary, these findings demonstrate the potential of Amuc_2109, as a therapeutic agent for ulcerative colitis. We posit that it will provide additional assistance in the prevention and treatment of mucus layer-related diseases such as ulcerative colitis.
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Affiliation(s)
- Kaiyue Qian
- School of Life Sciences, Anhui University, Hefei 230601, Anhui, China. .,Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei 230601, Anhui, China
| | - Shoujun Chen
- School of Life Sciences, Anhui University, Hefei 230601, Anhui, China. .,Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei 230601, Anhui, China
| | - Junchao Wang
- School of Life Sciences, Anhui University, Hefei 230601, Anhui, China. .,Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei 230601, Anhui, China.,Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China
| | - Kangliang Sheng
- School of Life Sciences, Anhui University, Hefei 230601, Anhui, China. .,Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei 230601, Anhui, China
| | - Yongzhong Wang
- School of Life Sciences, Anhui University, Hefei 230601, Anhui, China. .,Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei 230601, Anhui, China
| | - Min Zhang
- School of Life Sciences, Anhui University, Hefei 230601, Anhui, China. .,Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei 230601, Anhui, China
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Functional and structural characterization of a GH3 β-N-acetylhexosaminidase from Akkermansia muciniphila involved in mucin degradation. Biochem Biophys Res Commun 2021; 589:186-191. [PMID: 34922201 DOI: 10.1016/j.bbrc.2021.12.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 12/07/2021] [Indexed: 01/06/2023]
Abstract
Akkermansia muciniphila is a probiotic that colonizes the outer layer of intestinal mucus and is negatively associated with metabolic disorders. Amuc_2109 protein, a β-N-acetylhexosaminidase from A. muciniphila, may be involved in the degradation of mucins and is associated with intestinal health. Here, we reported the crystal structure of Amuc_2109, which belongs to the GH family 3 enzymes and fell into the canonical (α/β)8 TIM barrel structure with GlcNAc bound to the active center. Biochemical assay characterization of Amuc_2109 revealed that Amuc_2109 is a GlcNAc-specific glycosidase active over a wide temperature and pH range, reflecting the survival advantage of Amuc_2109 in the intestinal environment. Our structural and biochemical results will contribute to the understanding of the catalytic mechanism of the GH3 β-N-acetylhexosaminidase and help to gain insight into the molecular mechanism of complex carbohydrate utilization and restoration of the intestinal barrier in A. muciniphila.
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Bell A, Juge N. Mucosal glycan degradation of the host by the gut microbiota. Glycobiology 2020; 31:691-696. [PMID: 33043970 PMCID: PMC8252862 DOI: 10.1093/glycob/cwaa097] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/21/2020] [Accepted: 10/02/2020] [Indexed: 12/15/2022] Open
Abstract
The gut microbiota plays a major role in human health and an alteration in gut microbiota structure and function has been implicated in several diseases. In the colon, mucus covering the epithelium is critical to maintain a homeostatic relationship with the gut microbiota by harboring a microbial community at safe distance from the epithelium surface. The mucin glycans composing the mucus layer provide binding sites and a sustainable source of nutrients to the bacteria inhabiting the mucus niche. Access to these glycan chains requires a complement of glycoside hydrolases (GHs) produced by bacteria across the phyla constituting the human gut microbiota. Due to the increased recognition of the role of mucus-associated microbes in human health, how commensal bacteria breakdown and utilize host mucin glycans has become of increased interest and is reviewed here. This short review provides an overview of the strategies evolved by gut commensal bacteria to access this rich source of the nutrient with a focus on the GHs involved in mucin degradation.
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Affiliation(s)
- Andrew Bell
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Rosalind Franklin Road Norwich Research Park, Norwich NR4 7UQ, UK
| | - Nathalie Juge
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Rosalind Franklin Road Norwich Research Park, Norwich NR4 7UQ, UK
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Xu W, Yang W, Wang Y, Wang M, Zhang M. Structural and biochemical analyses of β-N-acetylhexosaminidase Am0868 from Akkermansia muciniphila involved in mucin degradation. Biochem Biophys Res Commun 2020; 529:876-881. [PMID: 32819592 DOI: 10.1016/j.bbrc.2020.06.116] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 06/23/2020] [Indexed: 12/30/2022]
Abstract
β-N-acetylhexosaminidases from the gut microbes are found to be capable of cleaving the specific glycoside linkages in the process of mucin degradation that has relevance for human health. However, features of the enzyme used in regulating the sugar-degrading capacities of Akkermansia muciniphila have not been well defined. Here we reported the crystal structure of a novel β-N-acetylhexosaminidase from Akkermansia muciniphila (Am0868), which displayed a typical (β/α) 8 barrel fold with a GlcNAc bound to the active center. Crystallographic and subsequent mutagenic analyses confirmed that Asp326 and Glu327 are the key catalytic residues of Am0868. Furthermore, Am0868 exhibited high specificity to β-GlcNAc supporting the substrate-assisted catalytic mechanism. Am0868 was also active in a broad pH and temperature range but inhibited strongly by metal ions Zn2+ and Cu2+. Collectively, these results indicate that Am0868 has the potential for mucin hydrolysis under some severe conditions, which highlight the superiority of A. muciniphila surviving in gut.
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Affiliation(s)
- Wenjuan Xu
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China
| | - Wenyi Yang
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China
| | - Yongzhong Wang
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China
| | - Mingzhu Wang
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China; Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, China.
| | - Min Zhang
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China.
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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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