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You Y, Kong H, Li C, Gu Z, Ban X, Li Z. Carbohydrate binding modules: Compact yet potent accessories in the specific substrate binding and performance evolution of carbohydrate-active enzymes. Biotechnol Adv 2024; 73:108365. [PMID: 38677391 DOI: 10.1016/j.biotechadv.2024.108365] [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: 12/11/2023] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 04/29/2024]
Abstract
Carbohydrate binding modules (CBMs) are independent non-catalytic domains widely found in carbohydrate-active enzymes (CAZymes), and they play an essential role in the substrate binding process of CAZymes by guiding the appended catalytic modules to the target substrates. Owing to their precise recognition and selective affinity for different substrates, CBMs have received increasing research attention over the past few decades. To date, CBMs from different origins have formed a large number of families that show a variety of substrate types, structural features, and ligand recognition mechanisms. Moreover, through the modification of specific sites of CBMs and the fusion of heterologous CBMs with catalytic domains, improved enzymatic properties and catalytic patterns of numerous CAZymes have been achieved. Based on cutting-edge technologies in computational biology, gene editing, and protein engineering, CBMs as auxiliary components have become portable and efficient tools for the evolution and application of CAZymes. With the aim to provide a theoretical reference for the functional research, rational design, and targeted utilization of novel CBMs in the future, we systematically reviewed the function-related characteristics and potentials of CAZyme-derived CBMs in this review, including substrate recognition and binding mechanisms, non-catalytic contributions to enzyme performances, module modifications, and innovative applications in various fields.
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Affiliation(s)
- Yuxian You
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China
| | - Haocun Kong
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Caiming Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China
| | - Zhengbiao Gu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xiaofeng Ban
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Zhaofeng Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China.
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Shi Q, Abdel-Hamid AM, Sun Z, Cheng Y, Tu T, Cann I, Yao B, Zhu W. Carbohydrate-binding modules facilitate the enzymatic hydrolysis of lignocellulosic biomass: Releasing reducing sugars and dissociative lignin available for producing biofuels and chemicals. Biotechnol Adv 2023; 65:108126. [PMID: 36921877 DOI: 10.1016/j.biotechadv.2023.108126] [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: 11/18/2022] [Revised: 02/05/2023] [Accepted: 03/08/2023] [Indexed: 03/16/2023]
Abstract
The microbial decomposition and utilization of lignocellulosic biomass present in the plant tissues are driven by a series of carbohydrate active enzymes (CAZymes) acting in concert. As the non-catalytic domains widely found in the modular CAZymes, carbohydrate-binding modules (CBMs) are intimately associated with catalytic domains (CDs) that effect the diverse hydrolytic reactions. The CBMs function as auxiliary components for the recognition, adhesion, and depolymerization of the complex substrate mediated by the associated CDs. Therefore, CBMs are deemed as significant biotools available for enzyme engineering, especially to facilitate the enzymatic hydrolysis of dense and insoluble plant tissues to acquire more fermentable sugars. This review aims at presenting the taxonomies and biological properties of the CBMs currently curated in the CAZy database. The molecular mechanisms that CBMs use in assisting the enzymatic hydrolysis of plant polysaccharides and the regulatory factors of CBM-substrate interactions are outlined in detail. In addition, guidelines for the rational designs of CBM-fused CAZymes are proposed. Furthermore, the potential to harness CBMs for industrial applications, especially in enzymatic pretreatment of the recalcitrant lignocellulose, is evaluated. It is envisaged that the ideas outlined herein will aid in the engineering and production of novel CBM-fused enzymes to facilitate efficient degradation of lignocellulosic biomass to easily fermentable sugars for production of value-added products, including biofuels.
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Affiliation(s)
- Qicheng Shi
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
| | - Ahmed M Abdel-Hamid
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, IL 61801, USA
| | - Zhanying Sun
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanfen Cheng
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China.
| | - Tao Tu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Isaac Cann
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, IL 61801, USA; Department of Animal Science, University of Illinois at Urbana-Champaign, IL 61801, USA; Department of Microbiology, University of Illinois at Urbana-Champaign, IL 61801, USA; Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, IL 61801, USA; Center for East Asian and Pacific Studies, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Bin Yao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Weiyun Zhu
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
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Butyrate-producing colonic clostridia: picky glycan utilization specialists. Essays Biochem 2022; 67:415-428. [PMID: 36350044 DOI: 10.1042/ebc20220125] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/18/2022] [Accepted: 10/21/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Butyrate-producing human gut microbiota members are recognized for their strong association with a healthy immune-homeostasis and protection from inflammatory disorders and colorectal cancer. These effects are attributed to butyrate, the terminal electron sink of glycan fermentation by prevalent and abundant colonic Firmicutes from the Lachnospiraceae and Oscillospiraceae families. Remarkably, our insight into the glycan utilization mechanisms and preferences of butyrogenic Firmicutes remains very limited as compared with other gut symbionts, especially from the Bacteroides, Bifidobacterium, and Lactobacillus genera. Here, we summarize recent findings on the strategies that colonic butyrate producers have evolved to harvest energy from major dietary fibres, especially plant structural and storage glycans, such as resistant starch, xylans, and mannans. Besides dietary fibre, we also present the unexpected discovery of a conserved protein apparatus that confers the growth of butyrate producers on human milk oligosaccharides (HMOs), which are unique to mother’s milk. The dual dietary fibre/HMO utilization machinery attests the adaptation of this group to both the infant and adult guts. These finding are discussed in relation to the early colonization of butyrogenic bacteria and the maturation of the microbiota during the transition from mother’s milk to solid food. To date, the described butyrogenic Firmicutes are glycan utilization specialists that target only a few glycans in a highly competitive manner relying on co-regulated glycan utilization loci. We describe the common pillars of this machinery, highlighting butyrate producers as a source for discovery of biochemically and structurally novel carbohydrate active enzymes.
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Zhang C, Ma K, Nie K, Deng M, Luo W, Wu X, Huang Y, Wang X. Assessment of the safety and probiotic properties of Roseburia intestinalis: A potential “Next Generation Probiotic”. Front Microbiol 2022; 13:973046. [PMID: 36160246 PMCID: PMC9493362 DOI: 10.3389/fmicb.2022.973046] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 08/05/2022] [Indexed: 12/04/2022] Open
Abstract
Roseburia intestinalis is an anaerobic bacterium that produces butyric acid and belongs to the phylum Firmicutes. There is increasing evidence that this bacterium has positive effects on several diseases, including inflammatory bowel disease, atherosclerosis, alcoholic fatty liver, colorectal cancer, and metabolic syndrome, making it a potential “Next Generation Probiotic.” We investigated the genomic characteristics, probiotic properties, cytotoxicity, oral toxicity, colonization characteristics of the bacterium, and its effect on the gut microbiota. The genome contains few genes encoding virulence factors, three clustered regularly interspaced short palindromic repeat (CRISPR) sequences, two Cas genes, no toxic biogenic amine synthesis genes, and several essential amino acid and vitamin synthesis genes. Seven prophages and 41 genomic islands were predicted. In addition to a bacteriocin (Zoocin A), the bacterium encodes four metabolic gene clusters that synthesize short-chain fatty acids and 222 carbohydrate-active enzyme modules. This bacterium is sensitive to antibiotics specified by the European Food Safety Authority, does not exhibit hemolytic or gelatinase activity, and exhibits some acid resistance. R. intestinalis adheres to intestinal epithelial cells and inhibits the invasion of certain pathogens. In vitro experiments showed that the bacterium was not cytotoxic. R. intestinalis did not affect the diversity or abundance of the gut flora. Using the fluorescent labelling method, we discovered that R. intestinalis colonizes the cecum and mucus of the colon. An oral toxicity study did not reveal any obvious adverse effects. The lethal dose (LD)50 of R. intestinalis exceeded 1.9 × 109 colony forming units (CFU)/kg, whereas the no observed adverse effect level (NOAEL) derived from this study was 1.32 × 109 CFU/kg/day for 28 days. The current research shows that, R. intestinalis is a suitable next-generation probiotic considering its probiotic properties and safety.
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Affiliation(s)
- Chao Zhang
- Department of Gastroenterology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Kejia Ma
- Department of Gastroenterology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Kai Nie
- Department of Gastroenterology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Minzi Deng
- Department of Gastroenterology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Weiwei Luo
- Department of Gastroenterology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Xing Wu
- Department of Gastroenterology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Yujun Huang
- Department of Gastroenterology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Xiaoyan Wang
- Department of Gastroenterology, The Third Xiangya Hospital of Central South University, Changsha, China
- Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
- *Correspondence: Xiaoyan Wang,
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Tanno H, Fujii T, Hirano K, Maeno S, Tonozuka T, Sakamoto M, Ohkuma M, Tochio T, Endo A. Characterization of fructooligosaccharide metabolism and fructooligosaccharide-degrading enzymes in human commensal butyrate producers. Gut Microbes 2022; 13:1-20. [PMID: 33439065 PMCID: PMC7833758 DOI: 10.1080/19490976.2020.1869503] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Butyrate produced by gut microbiota has multiple beneficial effects on host health, and oligosaccharides derived from host diets and glycans originating from host mucus are major sources of its production. A significant reduction of butyrate-producing bacteria has been reported in patients with inflammatory bowel diseases and colorectal cancers. Although gut butyrate levels are important for host health, oligosaccharide metabolic properties in butyrate producers are poorly characterized. We studied the metabolic properties of fructooligosaccharides (FOSs) and other prebiotic oligosaccharides (i.e. raffinose and xylooligosaccharides; XOSs) in gut butyrate producers. 1-Kestose (kestose) and nystose, FOSs with degrees of polymerization of 3 and 4, respectively, were also included. Fourteen species of butyrate producers were divided into four groups based on their oligosaccharide metabolic properties, which are group A (two species) metabolizing all oligosaccharides tested, group F (four species) metabolizing FOSs but not raffinose and XOSs, group XR (four species) metabolizing XOSs and/or raffinose but not FOSs, and group N (four species) metabolizing none of the oligosaccharides tested. Species assigned to groups A and XR are rich glycoside hydrolase (GH) holders, whereas those in groups F and N are the opposite. In total, 17 enzymes assigned to GH32 were observed in nine of the 14 butyrate producers tested, and species that metabolized FOSs had at least one active GH32 enzyme. The GH32 enzymes were divided into four clusters by phylogenetic analysis. Heterologous gene expression analysis revealed that the GH32 enzymes in each cluster had similar FOS degradation properties within clusters, which may be linked to the conservation/substitution of amino acids to bind with substrates in GH32 enzymes. This study provides important knowledge to understand the impact of FOS supplementation on the activation of gut butyrate producers. Abbreviations: SCFA, short chain fatty acid; FOS, fructooligosaccharide; XOS, xylooligosaccharide; CAZy, Carbohydrate Active Enzymes; CBM, carbohydrate-binding module; PUL, polysaccharide utilization locus; S6PH sucrose-6-phosphate hydrolase.
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Affiliation(s)
- Hiroki Tanno
- Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, Hokkaido, Japan
| | | | | | - Shintaro Maeno
- Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, Hokkaido, Japan
| | - Takashi Tonozuka
- Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Mitsuo Sakamoto
- PRIME, Japan Agency for Medical Research and Development (AMED), Ibaraki, Japan,Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Research Center, Ibaraki, Japan
| | - Moriya Ohkuma
- Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Research Center, Ibaraki, Japan
| | | | - Akihito Endo
- Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, Hokkaido, Japan,CONTACT Akihito Endo Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, Hokkaido099-2493, Japan
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Nie K, Ma K, Luo W, Shen Z, Yang Z, Xiao M, Tong T, Yang Y, Wang X. Roseburia intestinalis: A Beneficial Gut Organism From the Discoveries in Genus and Species. Front Cell Infect Microbiol 2021; 11:757718. [PMID: 34881193 PMCID: PMC8647967 DOI: 10.3389/fcimb.2021.757718] [Citation(s) in RCA: 137] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/29/2021] [Indexed: 12/12/2022] Open
Abstract
Roseburia intestinalis is an anaerobic, Gram-positive, slightly curved rod-shaped flagellated bacterium that produces butyrate in the colon. R. intestinalis has been shown to prevent intestinal inflammation and maintain energy homeostasis by producing metabolites. Evidence shows that this bacterium contributes to various diseases, such as inflammatory bowel disease, type 2 diabetes mellitus, antiphospholipid syndrome, and atherosclerosis. This review reveals the potential therapeutic role of R. intestinalis in human diseases. Patients with inflammatory bowel disease exhibit significant changes in R. intestinalis abundance, and they may benefit a lot from modulations targeting R. intestinalis. The data reviewed here demonstrate that R. intestinalis plays its role in regulating barrier homeostasis, immune cells, and cytokine release through its metabolite butyrate, flagellin and other. Recent advancements in the application of primary culture technology, culture omics, single-cell sequencing, and metabonomics technology have improved research on Roseburia and revealed the benefits of this bacterium in human health and disease treatment.
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Affiliation(s)
- Kai Nie
- Department of Gastroenterology, The Third Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
| | - Kejia Ma
- Department of Gastroenterology, The Third Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
| | - Weiwei Luo
- Department of Gastroenterology, The Third Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
| | - Zhaohua Shen
- Department of Gastroenterology, The Third Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
| | - Zhenyu Yang
- Department of Gastroenterology, The Third Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
| | - Mengwei Xiao
- Department of Gastroenterology, The Third Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
| | - Ting Tong
- Department of Gastroenterology, The Third Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
| | - Yuanyuan Yang
- Department of Gastroenterology, The Third Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
| | - Xiaoyan Wang
- Department of Gastroenterology, The Third Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Cancer Research Institute, Central South University, Changsha, China
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Collinet A, Grimm P, Julliand S, Julliand V. Sequential Modulation of the Equine Fecal Microbiota and Fibrolytic Capacity Following Two Consecutive Abrupt Dietary Changes and Bacterial Supplementation. Animals (Basel) 2021; 11:ani11051278. [PMID: 33946811 PMCID: PMC8144951 DOI: 10.3390/ani11051278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/23/2021] [Accepted: 04/27/2021] [Indexed: 01/01/2023] Open
Abstract
Simple Summary The equine hindgut is colonized by microorganisms, some of which are involved in fiber digestion and are crucial for the horse’s nutrition and health. These key microorganisms are very sensitive to dietary changes, which have been identified as a risk factor for colics. This study assessed the stressful effect of two consecutive abrupt dietary changes on the diversity, the composition, and the activity of fecal microorganisms focusing on fibrolytic bacteria. Twelve horses were subjected to an abrupt change from forage to a concentrate-rich diet, followed by a second change from a concentrate to forage-rich diet 5 days later. Half of the horses were given a supplement of living bacteria as a probiotic. Two days after the sudden change from forage to concentrate diet, the proportions and types of microorganisms were altered drastically, as was their capacity to degrade fibers. After this dietary stress, it took 3–4 weeks of a high-fiber diet to recover the basal state. Supplementation with probiotics promoted an earlier recovery of fibrolytic bacteria after the dietary stress. Abrupt dietary changes should be limited in horse management to protect the hindgut microorganisms and their capacity to use forage fibers, and consequently to limit the development of colic. Abstract In horses, abrupt changes from high-fiber (HF) to high-starch (HS) diets can affect the cecal and colonic microbiota. This study investigated modifications and recovery of fecal microbiota after two consecutive abrupt dietary changes. Twelve horses fed HF for 2 weeks were changed to HS for 5 days then returned to HF for 7 weeks. Six received lactic acid bacteria supplementation. Bacterial population diversity, structure, and activity, especially fibrolysis, were assessed to obtain an overview of alteration in hindgut microbiota. Two days after the abrupt change from HF to HS, the findings in feces were consistent with those previously reported in the cecum and colon, with a decrease in fibrolytic activity and an increase in amylolytic activity. Fecal parameters stabilized at their basal level 3–4 weeks after the return to HF. A bloom of cellulolytic bacteria and lower pH were observed after 1.5 weeks, suggesting a higher level of fiber degradation. In supplemented horses the relative abundance of potentially fibrolytic genera was enhanced 2 days after HS and 2 days to 2–3 weeks after the return to HF. Fecal analysis could be a promising technique for monitoring hindgut microbial variations accompanying dietary changes.
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Affiliation(s)
- Axelle Collinet
- Lab To Field, 21000 Dijon, France; (A.C.); (P.G.); (S.J.)
- Unité Mixte de Recherche Procédés Alimentaires et Microbiologiques (UMR PAM) A 02.102, AgroSup Dijon, University Bourgogne Franche-Comté, 21000 Dijon, France
| | - Pauline Grimm
- Lab To Field, 21000 Dijon, France; (A.C.); (P.G.); (S.J.)
| | - Samy Julliand
- Lab To Field, 21000 Dijon, France; (A.C.); (P.G.); (S.J.)
| | - Véronique Julliand
- Unité Mixte de Recherche Procédés Alimentaires et Microbiologiques (UMR PAM) A 02.102, AgroSup Dijon, University Bourgogne Franche-Comté, 21000 Dijon, France
- Correspondence:
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Tamura K, Brumer H. Glycan utilization systems in the human gut microbiota: a gold mine for structural discoveries. Curr Opin Struct Biol 2020; 68:26-40. [PMID: 33285501 DOI: 10.1016/j.sbi.2020.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/20/2020] [Accepted: 11/01/2020] [Indexed: 12/17/2022]
Abstract
The complex glycans comprising 'dietary fiber' evade the limited repertoire of human digestive enzymes and hence feed the vast community of microbes in the lower gastrointestinal tract. As such, complex glycans drive the composition of the human gut microbiota and, in turn, influence diverse facets of our nutrition and health. To access these otherwise recalcitrant carbohydrates, gut bacteria produce coordinated, substrate-specific arsenals of carbohydrate-active enzymes, glycan-binding proteins, oligosaccharide transporters, and transcriptional regulators. A recent explosion of biochemical and enzymological studies of these systems has led to the discovery of manifold new carbohydrate-active enzyme (CAZyme) families. Crucially underpinned by structural biology, these studies have also provided unprecedented molecular insight into the exquisite specificity of glycan recognition in the diverse CAZymes and non-catalytic proteins from the HGM. The revelation of a multitude of new three-dimensional structures and substrate complexes constitutes a 'gold rush' in the structural biology of the human gut microbiota.
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Affiliation(s)
- Kazune Tamura
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada; Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
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