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Lu Z, Kvammen A, Li H, Hao M, Inman AR, Bulone V, McKee LS. A polysaccharide utilization locus from Chitinophaga pinensis simultaneously targets chitin and β-glucans found in fungal cell walls. mSphere 2023; 8:e0024423. [PMID: 37493618 PMCID: PMC10449523 DOI: 10.1128/msphere.00244-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 06/06/2023] [Indexed: 07/27/2023] Open
Abstract
In nature, complex carbohydrates are rarely found as pure isolated polysaccharides. Instead, bacteria in competitive environments are presented with glycans embedded in heterogeneous matrices such as plant or microbial cell walls. Members of the Bacteroidota phylum thrive in such ecosystems because they are efficient at extracting nutrients from complex substrates, secreting consortia of synergistic enzymes to release metabolizable sugars. Carbohydrate-binding modules (CBMs) are used to target enzymes to substrates, enhancing reaction rate and product release. Additionally, genome organizational tools like polysaccharide utilization loci (PULs) ensure that the appropriate set of enzymes is produced when needed. In this study, we show that the soil bacterium Chitinophaga pinensis uses a PUL and several CBMs to coordinate the activities of enzymes targeting two distinct polysaccharides found in fungal cell walls. We describe the enzymatic activities and carbohydrate-binding behaviors of components of the fungal cell wall utilization locus (FCWUL), which uses multiple chitinases and one β-1,3-glucanase to hydrolyze two different substrates. Unusually, one of the chitinases is appended to a β-glucan-binding CBM, implying targeting to a bulk cell wall substrate rather than to the specific polysaccharide being hydrolyzed. Based on our characterization of the PUL's outer membrane sensor protein, we suggest that the FCWUL is activated by β-1,3-glucans, even though most of its enzymes are chitin-degrading. Our data showcase the complexity of polysaccharide deconstruction in nature and highlight an elegant solution for how multiple different glycans can be accessed using one enzymatic cascade. IMPORTANCE We report that the genome of the soil bacterium Chitinophaga pinensis encodes three multi-modular carbohydrate-active enzymes that work together to hydrolyze the major polysaccharide components found in fungal cell walls (FCWs). The enzymes are all encoded by one polysaccharide utilization locus and are co-expressed, potentially induced in the presence of β-1,3-glucans. We present biochemical characterization of each enzyme, including the appended carbohydrate-binding modules that likely tether the enzymes to a FCW substrate. Finally, we propose a model for how this so-called fungal cell wall utilization locus might enable C. pinensis to metabolize both chitin and β-1,3-glucans found in complex biomass in the soil.
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Affiliation(s)
- Zijia Lu
- Department of Chemistry, Division of Glycoscience, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Alma Kvammen
- Department of Chemistry, Division of Glycoscience, KTH Royal Institute of Technology, Stockholm, Sweden
| | - He Li
- Department of Chemistry, Division of Glycoscience, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Mengshu Hao
- Department of Chemistry, Division of Glycoscience, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Annie R. Inman
- Department of Chemistry, Division of Glycoscience, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Vincent Bulone
- Department of Chemistry, Division of Glycoscience, KTH Royal Institute of Technology, Stockholm, Sweden
- College of Medicine and Public Health, Flinders University, Adelaide, Australia
| | - Lauren S. McKee
- Department of Chemistry, Division of Glycoscience, KTH Royal Institute of Technology, Stockholm, Sweden
- Wallenberg Wood Science Center, KTH Royal Institute of Technology, Stockholm, Sweden
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Plant chitinases and their role in plant defense – a comprehensive review. Enzyme Microb Technol 2022; 159:110055. [DOI: 10.1016/j.enzmictec.2022.110055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 04/07/2022] [Accepted: 04/25/2022] [Indexed: 12/22/2022]
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La Rosa SL, Ostrowski MP, Vera-Ponce de León A, McKee LS, Larsbrink J, Eijsink VG, Lowe EC, Martens EC, Pope PB. Glycan processing in gut microbiomes. Curr Opin Microbiol 2022; 67:102143. [PMID: 35338908 DOI: 10.1016/j.mib.2022.102143] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/10/2022] [Accepted: 02/21/2022] [Indexed: 12/16/2022]
Abstract
Microbiomes and their enzymes process many of the nutrients accessible in the gastrointestinal tract of bilaterians and play an essential role in host health and nutrition. In this review, we describe recent insights into nutrient processing in microbiomes across three exemplary yet contrasting gastrointestinal ecosystems (humans, ruminants and insects), with focus on bacterial mechanisms for the utilization of common and atypical dietary glycans as well as host-derived mucus glycans. In parallel, we discuss findings from multi-omic studies that have provided new perspectives on understanding glycan-dependent interactions and the complex food-webs of microbial populations in their natural habitat. Using key examples, we emphasize how increasing understanding of glycan processing by gut microbiomes can provide critical insights to assist 'microbiome reprogramming', a growing field that seeks to leverage diet to improve animal growth and host health.
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Affiliation(s)
| | - Matthew P Ostrowski
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, 48109, MI, USA
| | - Arturo Vera-Ponce de León
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1433, Norway
| | - Lauren S McKee
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, 106 91, Sweden
| | - Johan Larsbrink
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, 412 96, Sweden
| | - Vincent G Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1433, Norway
| | | | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, 48109, MI, USA
| | - Phillip B Pope
- Faculty of Biosciences, Norwegian University of Life Sciences, Ås, 1433, Norway; Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1433, Norway
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Mechanism of cooperative degradation of gum arabic arabinogalactan protein by Bifidobacterium longum surface enzymes. Appl Environ Microbiol 2022; 88:e0218721. [PMID: 35108084 PMCID: PMC8939339 DOI: 10.1128/aem.02187-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gum arabic is an arabinogalactan protein (AGP) that is effective as a prebiotic for the growth of bifidobacteria in the human intestine. We recently identified a key enzyme in the glycoside hydrolase (GH) family 39, 3-O-α-d-galactosyl-α-l-arabinofuranosidase (GAfase), for the assimilation of gum arabic AGP in Bifidobacterium longum subsp. longum. The enzyme released α-d-Galp-(1→3)-l-Ara and β-l-Arap-(1→3)-l-Ara from gum arabic AGP and facilitated the action of other enzymes for degrading the AGP backbone and modified sugar. In this study, we identified an α-l-arabinofuranosidase (BlArafE; encoded by BLLJ_1850), a multidomain enzyme with both GH43_22 and GH43_34 catalytic domains, as a critical enzyme for the degradation of modified α-l-arabinofuranosides in gum arabic AGP. Site-directed mutagenesis approaches revealed that the α1,3/α1,4-Araf double-substituted gum arabic AGP side chain was initially degraded by the GH43_22 domain and subsequently cleaved by the GH43_34 domain to release α1,3-Araf and α1,4-Araf residues, respectively. Furthermore, we revealed that a tetrasaccharide, α-l-Rhap-(1→4)-β-d-GlcpA-(1→6)-β-d-Galp-(1→6)-d-Gal, was a limited degradative oligosaccharide in the gum arabic AGP fermentation of B. longum subsp. longum JCM7052. The oligosaccharide was produced from gum arabic AGP by the cooperative action of the three cell surface-anchoring enzymes, GAfase, exo-β1,3-galactanase (Bl1,3Gal), and BlArafE, on B. longum subsp. longum JCM7052. Furthermore, the tetrasaccharide was utilized by the commensal bacteria. IMPORTANCE Terminal galactose residues of the side chain of gum arabic arabinogalactan protein (AGP) are mainly substituted by α1,3/α1,4-linked Araf and β1,6-linked α-l-Rhap-(1→4)-β-d-GlcpA residues. This study found a multidomain BlArafE with GH43_22 and GH43_34 catalytic domains showing cooperative action for degrading α1,3/α1,4-linked Araf of the side chain of gum arabic AGP. In particular, the GH43_34 domain of BlArafE was a novel α-l-arabinofuranosidase for cleaving the α1,4-Araf linkage of terminal galactose. α-l-Rhap-(1→4)-β-d-GlcpA-(1→6)-β-d-Galp-(1→6)-d-Gal tetrasaccharide was released from gum arabic AGP by the cooperative action of GAfase, GH43_24 exo-β-1,3-galactanase (Bl1,3Gal), and BlArafE and remained after B. longum subsp. longum JCM7052 culture. Furthermore, in vitro assimilation test of the remaining oligosaccharide using Bacteroides species revealed that cross-feeding may occur from bifidobacteria to other taxonomic groups in the gut.
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Parvulescu VI, Epron F, Garcia H, Granger P. Recent Progress and Prospects in Catalytic Water Treatment. Chem Rev 2021; 122:2981-3121. [PMID: 34874709 DOI: 10.1021/acs.chemrev.1c00527] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Presently, conventional technologies in water treatment are not efficient enough to completely mineralize refractory water contaminants. In this context, the implementation of catalytic processes could be an alternative. Despite the advantages provided in terms of kinetics of transformation, selectivity, and energy saving, numerous attempts have not yet led to implementation at an industrial scale. This review examines investigations at different scales for which controversies and limitations must be solved to bridge the gap between fundamentals and practical developments. Particular attention has been paid to the development of solar-driven catalytic technologies and some other emerging processes, such as microwave assisted catalysis, plasma-catalytic processes, or biocatalytic remediation, taking into account their specific advantages and the drawbacks. Challenges for which a better understanding related to the complexity of the systems and the coexistence of various solid-liquid-gas interfaces have been identified.
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Affiliation(s)
- Vasile I Parvulescu
- Department of Organic Chemistry, Biochemistry and Catalysis, University of Bucharest, B-dul Regina Elisabeta 4-12, Bucharest 030016, Romania
| | - Florence Epron
- Université de Poitiers, CNRS UMR 7285, Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), 4 rue Michel Brunet, TSA 51106, 86073 Poitiers Cedex 9, France
| | - Hermenegildo Garcia
- Instituto Universitario de Tecnología Química, Universitat Politecnica de Valencia-Consejo Superior de Investigaciones Científicas, Universitat Politencia de Valencia, Av. de los Naranjos s/n, 46022 Valencia, Spain
| | - Pascal Granger
- CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, Univ. Lille, F-59000 Lille, France
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McKee LS, La Rosa SL, Westereng B, Eijsink VG, Pope PB, Larsbrink J. Polysaccharide degradation by the Bacteroidetes: mechanisms and nomenclature. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:559-581. [PMID: 34036727 DOI: 10.1111/1758-2229.12980] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 05/22/2021] [Accepted: 05/23/2021] [Indexed: 06/12/2023]
Abstract
The Bacteroidetes phylum is renowned for its ability to degrade a wide range of complex carbohydrates, a trait that has enabled its dominance in many diverse environments. The best studied species inhabit the human gut microbiome and use polysaccharide utilization loci (PULs), discrete genetic structures that encode proteins involved in the sensing, binding, deconstruction, and import of target glycans. In many environmental species, polysaccharide degradation is tightly coupled to the phylum-exclusive type IX secretion system (T9SS), which is used for the secretion of certain enzymes and is linked to gliding motility. In addition, within specific species these two adaptive systems (PULs and T9SS) are intertwined, with PUL-encoded enzymes being secreted by the T9SS. Here, we discuss the most noteworthy PUL and non-PUL mechanisms that confer specific and rapid polysaccharide degradation capabilities to the Bacteroidetes in a range of environments. We also acknowledge that the literature showcasing examples of PULs is rapidly expanding and developing a set of assumptions that can be hard to track back to original findings. Therefore, we present a simple universal description of conserved PUL functions and how they are determined, while proposing a common nomenclature describing PULs and their components, to simplify discussion and understanding of PUL systems.
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Affiliation(s)
- Lauren S McKee
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, 106 91, Sweden
- Wallenberg Wood Science Center, Stockholm, 100 44, Sweden
| | | | - Bjørge Westereng
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Vincent G Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Phillip B Pope
- Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Johan Larsbrink
- Wallenberg Wood Science Center, Stockholm, 100 44, Sweden
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, 412 96, Sweden
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Kmezik C, Krska D, Mazurkewich S, Larsbrink J. Characterization of a novel multidomain CE15-GH8 enzyme encoded by a polysaccharide utilization locus in the human gut bacterium Bacteroides eggerthii. Sci Rep 2021; 11:17662. [PMID: 34480044 PMCID: PMC8417218 DOI: 10.1038/s41598-021-96659-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/11/2021] [Indexed: 11/13/2022] Open
Abstract
Bacteroidetes are efficient degraders of complex carbohydrates, much thanks to their use of polysaccharide utilization loci (PULs). An integral part of PULs are highly specialized carbohydrate-active enzymes, sometimes composed of multiple linked domains with discrete functions—multicatalytic enzymes. We present the biochemical characterization of a multicatalytic enzyme from a large PUL encoded by the gut bacterium Bacteroides eggerthii. The enzyme, BeCE15A-Rex8A, has a rare and novel architecture, with an N-terminal carbohydrate esterase family 15 (CE15) domain and a C-terminal glycoside hydrolase family 8 (GH8) domain. The CE15 domain was identified as a glucuronoyl esterase (GE), though with relatively poor activity on GE model substrates, attributed to key amino acid substitutions in the active site compared to previously studied GEs. The GH8 domain was shown to be a reducing-end xylose-releasing exo-oligoxylanase (Rex), based on having activity on xylooligosaccharides but not on longer xylan chains. The full-length BeCE15A-Rex8A enzyme and the Rex domain were capable of boosting the activity of a commercially available GH11 xylanase on corn cob biomass. Our research adds to the understanding of multicatalytic enzyme architectures and showcases the potential of discovering novel and atypical carbohydrate-active enzymes from mining PULs.
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Affiliation(s)
- Cathleen Kmezik
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Daniel Krska
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Scott Mazurkewich
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden.,Wallenberg Wood Science Center, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Johan Larsbrink
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden. .,Wallenberg Wood Science Center, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
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