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Walt HK, Ahn SJ, Hoffmann FG. Horizontally transferred glycoside hydrolase 26 may aid hemipteran insects in plant tissue digestion. Mol Phylogenet Evol 2024; 198:108134. [PMID: 38901473 DOI: 10.1016/j.ympev.2024.108134] [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: 04/15/2024] [Revised: 05/28/2024] [Accepted: 06/15/2024] [Indexed: 06/22/2024]
Abstract
Glycoside hydrolases are enzymes that break down complex carbohydrates into simple sugars by catalyzing the hydrolysis of glycosidic bonds. There have been multiple instances of adaptive horizontal gene transfer of genes belonging to various glycoside hydrolase families from microbes to insects, as glycoside hydrolases can metabolize constituents of the carbohydrate-rich plant cell wall. In this study, we characterize the horizontal transfer of a gene from the glycoside hydrolase family 26 (GH26) from bacteria to insects of the order Hemiptera. Our phylogenies trace the horizontal gene transfer to the common ancestor of the superfamilies Pentatomoidea and Lygaeoidea, which include stink bugs and seed bugs. After horizontal transfer, the gene was assimilated into the insect genome as indicated by the gain of an intron, and a eukaryotic signal peptide. Subsequently, the gene has undergone independent losses and expansions in copy number in multiple lineages, suggesting an adaptive role of GH26s in some insects. Finally, we measured tissue-level gene expression of multiple stink bugs and the large milkweed bug using publicly available RNA-seq datasets. We found that the GH26 genes are highly expressed in tissues associated with plant digestion, especially in the principal salivary glands of the stink bugs. Our results are consistent with the hypothesis that this horizontally transferred GH26 was co-opted by the insect to aid in plant tissue digestion and that this HGT event was likely adaptive.
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Affiliation(s)
- Hunter K Walt
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, USA
| | - Seung-Joon Ahn
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, USA
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, USA; Institute for Genomics, Biotechnology and Biocomputing, Mississippi State University, Mississippi State, MS 39762, USA.
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2
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Liu J, Shi J, Gao J, Shi R, Zhu J, Jensen MS, Li C, Yang J, Zhao S, Sun A, Sun D, Zhang Y, Liu C, Liu W. Functional studies on tandem carbohydrate-binding modules of a multimodular enzyme possessing two catalytic domains. Appl Environ Microbiol 2024; 90:e0088824. [PMID: 38940565 PMCID: PMC11267928 DOI: 10.1128/aem.00888-24] [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: 05/10/2024] [Accepted: 06/09/2024] [Indexed: 06/29/2024] Open
Abstract
Although functional studies on carbohydrate-binding module (CBM) have been carried out extensively, the role of tandem CBMs in the enzyme containing multiple catalytic domains (CDs) is unclear. Here, we identified a multidomain enzyme (Lc25986) with a novel modular structure from lignocellulolytic bacterial consortium. It consists of a mannanase domain, two CBM65 domains (LcCBM65-1/LcCBM65-2), and an esterase domain. To investigate CBM function and domain interactions, full-length Lc25986 and its variants were constructed and used for enzymatic activity, binding, and bioinformatic analyses. The results showed that LcCBM65-1 and LcCBM65-2 both bind mannan and xyloglucan but not cellulose or β-1,3-1,4-glucan, which differs from the ligand specificity of reported CBM65s. Compared to LcCBM65-2, LcCBM65-1 showed a stronger ligand affinity and a preference for acetylation sites. Both CBM65s stimulated the enzymatic activities of their respective neighboring CDs against acetylated mannan, but did not contribute to the activities of the distal CDs. The time course of mannan hydrolysis indicated that the full-length Lc25986 was more effective in the complete degradation of mixed acetyl/non-acetyl substrates than the mixture of single-CD mutants. When acting on complex substrates, LcCBM65-1 not only improved the enzymatic activity of the mannanase domain, but also directed the esterase domain to the acetylated polysaccharides. LcCBM65-2 adopted a low affinity to reduce interference with the catalysis of the mannanase domain. These results demonstrate the importance of CBMs for the synergism between the two CDs of a multidomain enzyme and suggest that they contribute to the adequate degradation of complex substrates such as plant cell walls. IMPORTANCE Lignocellulolytic enzymes, particularly those of bacterial origin, often harbor multiple carbohydrate-binding modules (CBMs). However, the function of CBM multivalency remains poorly understood. This is especially true for enzymes that contain more than one catalytic domain (CD), as the interactions between CDs, CBMs, and CDs and CBMs can be complex. Our research demonstrates that homogeneous CBMs can have distinct functions in a multimodular enzyme. The tandem CBMs coordinate the CDs in catalytic conflict through their differences in binding affinity, ligand preference, and arrangement within the full-length enzyme. Additionally, although the synergism between mannanase and esterase is widely acknowledged, our study highlights the benefits of integrating the two enzymes into a single entity for the degradation of complex substrates. In summary, these findings enhance our understanding of the intra-synergism of a multimodular enzyme and emphasize the significance of multiple CBMs in this context.
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Affiliation(s)
- Jiawen Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jiani Shi
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jiahui Gao
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Rui Shi
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jingrong Zhu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Marcus Sepo Jensen
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Chenchen Li
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jing Yang
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Siyi Zhao
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Aofei Sun
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Di Sun
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Ying Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Cong Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Weijie Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
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3
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Lamote B, da Fonseca MJM, Vanderstraeten J, Meert K, Elias M, Briers Y. Current challenges in designer cellulosome engineering. Appl Microbiol Biotechnol 2023; 107:2755-2770. [PMID: 36941434 DOI: 10.1007/s00253-023-12474-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 02/28/2023] [Accepted: 03/03/2023] [Indexed: 03/23/2023]
Abstract
Designer cellulosomes (DCs) are engineered multi-enzyme complexes, comprising carbohydrate-active enzymes attached to a common backbone, the scaffoldin, via high-affinity cohesin-dockerin interactions. The use of DCs in the degradation of renewable biomass polymers is a promising approach for biorefineries. Indeed, DCs have shown significant hydrolytic activities due to the enhanced enzyme-substrate proximity and inter-enzyme synergies, but technical hurdles in DC engineering have hindered further progress towards industrial application. The challenge in DC engineering lies in the large diversity of possible building blocks and architectures, resulting in a multivariate and immense design space. Simultaneously, the precise DC composition affects many relevant parameters such as activity, stability, and manufacturability. Since protein engineers face a lack of high-throughput approaches to explore this vast design space, DC engineering may result in an unsatisfying outcome. This review provides a roadmap to guide researchers through the process of DC engineering. Each step, starting from concept to evaluation, is described and provided with its challenges, along with possible solutions, both for DCs that are assembled in vitro or are displayed on the yeast cell surface. KEY POINTS: • Construction of designer cellulosomes is a multi-step process. • Designer cellulosome research deals with multivariate construction challenges. • Boosting designer cellulosome efficiency requires exploring a vast design space.
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Affiliation(s)
- Babette Lamote
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, Ghent, Belgium
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Ghent, Belgium
| | | | - Julie Vanderstraeten
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Kenan Meert
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, Ghent, Belgium
- Laboratory of Applied Mycology and Phenomics, Department of Plants and Crops, Ghent University, Ghent, Belgium
| | - Marte Elias
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, Ghent, Belgium
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Yves Briers
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, Ghent, Belgium.
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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: 6] [Impact Index Per Article: 6.0] [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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5
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Novak JK, Gardner JG. Galactomannan utilization by Cellvibrio japonicus relies on a single essential α-galactosidase encoded by the aga27A gene. Mol Microbiol 2023; 119:312-325. [PMID: 36604822 DOI: 10.1111/mmi.15024] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/22/2022] [Accepted: 12/30/2022] [Indexed: 01/07/2023]
Abstract
Plant mannans are a component of lignocellulose that can have diverse compositions in terms of its backbone and side-chain substitutions. Consequently, the degradation of mannan substrates requires a cadre of enzymes for complete reduction to substituent monosaccharides that can include mannose, galactose, and/or glucose. One bacterium that possesses this suite of enzymes is the Gram-negative saprophyte Cellvibrio japonicus, which has 10 predicted mannanases from the Glycoside Hydrolase (GH) families 5, 26, and 27. Here we describe a systems biology approach to identify and characterize the essential mannan-degrading components in this bacterium. The transcriptomic analysis uncovered significant changes in gene expression for most mannanases, as well as many genes that encode carbohydrate active enzymes (CAZymes) when mannan was actively being degraded. A comprehensive mutational analysis characterized 54 CAZyme-encoding genes in the context of mannan utilization. Growth analysis of the mutant strains found that the man26C, aga27A, and man5D genes, which encode a mannobiohydrolase, α-galactosidase, and mannosidase, respectively, were important for the deconstruction of galactomannan, with Aga27A being essential. Our updated model of mannan degradation in C. japonicus proposes that the removal of galactose sidechains from substituted mannans constitutes a crucial step for the complete degradation of this hemicellulose.
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Affiliation(s)
- Jessica K Novak
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, Maryland, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, Maryland, USA
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6
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Yu L, Yoshimi Y, Cresswell R, Wightman R, Lyczakowski JJ, Wilson LFL, Ishida K, Stott K, Yu X, Charalambous S, Wurman-Rodrich J, Terrett OM, Brown SP, Dupree R, Temple H, Krogh KBRM, Dupree P. Eudicot primary cell wall glucomannan is related in synthesis, structure, and function to xyloglucan. THE PLANT CELL 2022; 34:4600-4622. [PMID: 35929080 PMCID: PMC9614514 DOI: 10.1093/plcell/koac238] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Hemicellulose polysaccharides influence assembly and properties of the plant primary cell wall (PCW), perhaps by interacting with cellulose to affect the deposition and bundling of cellulose fibrils. However, the functional differences between plant cell wall hemicelluloses such as glucomannan, xylan, and xyloglucan (XyG) remain unclear. As the most abundant hemicellulose, XyG is considered important in eudicot PCWs, but plants devoid of XyG show relatively mild phenotypes. We report here that a patterned β-galactoglucomannan (β-GGM) is widespread in eudicot PCWs and shows remarkable similarities to XyG. The sugar linkages forming the backbone and side chains of β-GGM are analogous to those that make up XyG, and moreover, these linkages are formed by glycosyltransferases from the same CAZy families. Solid-state nuclear magnetic resonance indicated that β-GGM shows low mobility in the cell wall, consistent with interaction with cellulose. Although Arabidopsis β-GGM synthesis mutants show no obvious growth defects, genetic crosses between β-GGM and XyG mutants produce exacerbated phenotypes compared with XyG mutants. These findings demonstrate a related role of these two similar but distinct classes of hemicelluloses in PCWs. This work opens avenues to study the roles of β-GGM and XyG in PCWs.
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Affiliation(s)
- Li Yu
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Yoshihisa Yoshimi
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK
| | | | - Raymond Wightman
- Microscopy Core Facility, Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK
| | | | | | - Konan Ishida
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Katherine Stott
- Department of Biochemistry, University of Cambridge, Sanger Building, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Xiaolan Yu
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Stephan Charalambous
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK
| | | | - Oliver M Terrett
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Steven P Brown
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
| | - Ray Dupree
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
| | - Henry Temple
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK
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Novel Nematode-Killing Protein-1 (Nkp-1) from a Marine Epiphytic Bacterium Pseudoalteromonas tunicata. Biomedicines 2021; 9:biomedicines9111586. [PMID: 34829814 PMCID: PMC8615270 DOI: 10.3390/biomedicines9111586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/22/2021] [Accepted: 10/22/2021] [Indexed: 12/12/2022] Open
Abstract
Drug resistance among parasitic nematodes has resulted in an urgent need for the development of new therapies. However, the high re-discovery rate of anti-nematode compounds from terrestrial environments necessitates a new repository for future drug research. Marine epiphytes are hypothesised to produce nematicidal compounds as a defence against bacterivorous predators, thus representing a promising yet underexplored source for anti-nematode drug discovery. The marine epiphytic bacterium Pseudoalteromonas tunicata is known to produce several bioactive compounds. Screening heterologously expressed genomic libraries of P. tunicata against the nematode Caenorhabditis elegans, identified as an E. coli clone (HG8), shows fast-killing activity. Here we show that clone HG8 produces a novel nematode-killing protein-1 (Nkp-1) harbouring a predicted carbohydrate-binding domain with weak homology to known bacterial pore-forming toxins. We found bacteria expressing Nkp-1 were able to colonise the C. elegans intestine, with exposure to both live bacteria and protein extracts resulting in physical damage and necrosis, leading to nematode death within 24 h of exposure. Furthermore, this study revealed C. elegans dar (deformed anal region) and internal hatching may act as a nematode defence strategy against Nkp-1 toxicity. The characterisation of this novel protein and putative mode of action not only contributes to the development of novel anti-nematode applications in the future but reaffirms the potential of marine epiphytic bacteria as a new source of novel biomolecules.
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8
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Chavan RR, Singh AP, Azizan A, Harris PJ. Heteromannans are the predominant hemicelluloses in the gametophytic stem of the umbrella moss Hypnodendron menziesii and occur in the walls of all cell types. PLANTA 2021; 254:2. [PMID: 34085144 DOI: 10.1007/s00425-021-03650-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
Heteromannans are the predominant hemicelluloses in the gametophytic stem of the moss Hypnodendron menziesii and occur in the walls of all cell types Little is known about the cell-wall polysaccharides of mosses. Monosaccharide analysis of cell walls isolated from the stem of the umbrella moss Hypnodendron menziesii was consistent with heteromannans, probably galactoglucomannans, being the predominant hemicellulosic polysaccharides in the walls. Immunofluorescence and immunogold microscopy with the monoclonal antibody LM21, specific for heteromannans, showed that these polysaccharides were present in the walls of all stem cell types. These cell types, except the hydroids, have secondary walls. Experiments in which sections were pre-treated with 0.1 M sodium carbonate and with the enzyme pectate lyase indicated that the heteromannans have O-acetyl groups that limit LM21 binding and the cell walls contain pectic homogalacturonan that masks detection of heteromannans using LM21. Therefore, to fully detect heteromannans in the cell walls, it was essential to use these pre-treatments to remove the O-acetyl groups from the heteromannans and pectic homogalacturonan from the cell walls. Fluorescence microscopy experiments with a second monoclonal antibody, LM22, also specific for heteromannans, showed similar results, but the binding was considerably weaker than with LM21, possibly as a result of subtle structural differences in the epitopes of the two antibodies. Although heteromannans occur abundantly in the cell walls of many species in basal lineages of tracheophytes, prior to the present study, research on the distribution of these polysaccharides in the walls of different cell types in mosses was confined to the model species Physcomitrium patens.
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Affiliation(s)
- Ramesh R Chavan
- School of Biological Sciences, The University of Auckland, Auckland Mail Centre, Private Bag 92019, Auckland, 1142, New Zealand
| | - Adya P Singh
- School of Biological Sciences, The University of Auckland, Auckland Mail Centre, Private Bag 92019, Auckland, 1142, New Zealand
| | - Awanis Azizan
- School of Biological Sciences, The University of Auckland, Auckland Mail Centre, Private Bag 92019, Auckland, 1142, New Zealand
- Faculty of Health and Environmental Sciences, Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand
| | - Philip J Harris
- School of Biological Sciences, The University of Auckland, Auckland Mail Centre, Private Bag 92019, Auckland, 1142, New Zealand.
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9
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Pinheiro MP, Reis RA, Dupree P, Ward RJ. Plant cell wall architecture guided design of CBM3-GH11 chimeras with enhanced xylanase activity using a tandem repeat left-handed β-3-prism scaffold. Comput Struct Biotechnol J 2021; 19:1108-1118. [PMID: 33680354 PMCID: PMC7890094 DOI: 10.1016/j.csbj.2021.01.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 01/19/2023] Open
Abstract
Effective use of plant biomass as an abundant and renewable feedstock for biofuel production and biorefinery requires efficient enzymatic mobilization of cell wall polymers. Knowledge of plant cell wall composition and architecture has been exploited to develop novel multifunctional enzymes with improved activity against lignocellulose, where a left-handed β-3-prism synthetic scaffold (BeSS) was designed for insertion of multiple protein domains at the prism vertices. This allowed construction of a series of chimeras fusing variable numbers of a GH11 β-endo-1,4-xylanase and the CipA-CBM3 with defined distances and constrained relative orientations between catalytic domains. The cellulose binding and endoxylanase activities of all chimeras were maintained. Activity against lignocellulose substrates revealed a rapid 1.6- to 3-fold increase in total reducing saccharide release and increased levels of all major oligosaccharides as measured by polysaccharide analysis using carbohydrate gel electrophoresis (PACE). A construct with CBM3 and GH11 domains inserted in the same prism vertex showed highest activity, demonstrating interdomain geometry rather than number of catalytic sites is important for optimized chimera design. These results confirm that the BeSS concept is robust and can be successfully applied to the construction of multifunctional chimeras, which expands the possibilities for knowledge-based protein design.
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Affiliation(s)
- Matheus P. Pinheiro
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP CEP 14040-901, Brazil
| | - Renata A.G. Reis
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Ribeirão Preto, SP CEP 14040-901, Brazil
| | - Paul Dupree
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Richard J. Ward
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP CEP 14040-901, Brazil
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10
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Liu Z, Liang Q, Wang P, Kong Q, Fu X, Mou H. Improving the kinetic stability of a hyperthermostable β-mannanase by a rationally combined strategy. Int J Biol Macromol 2020; 167:405-414. [PMID: 33278432 DOI: 10.1016/j.ijbiomac.2020.11.202] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/24/2020] [Accepted: 11/29/2020] [Indexed: 01/09/2023]
Abstract
Feasible and easily accessible methods for the rational design of enzyme engineering strategies remain to be established. Thus, a new rationally combined strategy based on disulfide bond engineering and HotSpot Wizard 3.0 was proposed and experimentally demonstrated to be effective using a hyperthermostable β-mannanase. Ten of 42 mutants showed prominent enhancement of kinetic stability with 26.4%-39.9% increases in t1/2 (75 °C) compared with the parent enzyme ManAKH. The best mutant, D273-V308, showed apparent increases in both optimal temperature (5 °C) and T50 (6.8 °C), as well as advanced catalytic efficiency. The low rate of inactive mutants and the high rate of positive mutants indicated that newly introduced screening factors (distance from catalytic residues, Gibbs free energy term, molecular simulation, and visual inspections) greatly enhance the design of thermostable β-mannanase. Moreover, these findings further advance the industrial application of β-mannanase (ManAK) in food and food-related applications.
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Affiliation(s)
- Zhemin Liu
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Qingping Liang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Peng Wang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Qing Kong
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Xiaodan Fu
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Haijin Mou
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China.
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Kaira GS, Kapoor M. Molecular advancements on over-expression, stability and catalytic aspects of endo-β-mannanases. Crit Rev Biotechnol 2020; 41:1-15. [PMID: 33032458 DOI: 10.1080/07388551.2020.1825320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The hydrolysis of mannans by endo-β-mannanases continues to gather significance as exemplified by its commercial applications in food, feed, and a rekindled interest in biorefineries. The present review provides a comprehensive account of fundamental research and fascinating insights in the field of endo-β-mannanase engineering in order to improve over-expression and to decipher molecular determinants governing activity-stability during harsh conditions, substrate recognition, polysaccharide specificity, endo/exo mode of action and multi-functional activities in the modular polypeptide. In-depth analysis of the available literature has also been made on rational and directed evolution approaches, which have translated native endo-β-mannanases into superior biocatalysts for satisfying industrial requirements.
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Affiliation(s)
- Gaurav Singh Kaira
- Department of Protein Chemistry and Technology, CSIR-Central Food Technological Research Institute, Mysuru, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Mukesh Kapoor
- Department of Protein Chemistry and Technology, CSIR-Central Food Technological Research Institute, Mysuru, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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12
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Galloway AF, Akhtar J, Marcus SE, Fletcher N, Field K, Knox P. Cereal root exudates contain highly structurally complex polysaccharides with soil-binding properties. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1666-1678. [PMID: 32463959 DOI: 10.1111/tpj.14852] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 04/30/2020] [Accepted: 05/12/2020] [Indexed: 05/21/2023]
Abstract
Rhizosheaths function in plant-soil interactions, and are proposed to form due to a mix of soil particle entanglement in root hairs and the action of adhesive root exudates. The soil-binding factors released into rhizospheres to form rhizosheaths have not been characterised. Analysis of the high-molecular-weight (HMW) root exudates of both wheat and maize plants indicate the presence of complex, highly branched polysaccharide components with a wide range of galactosyl, glucosyl and mannosyl linkages that do not directly reflect cereal root cell wall polysaccharide structures. Periodate oxidation indicates that it is the carbohydrate components of the HMW exudates that have soil-binding properties. The root exudates contain xyloglucan (LM25), heteroxylan (LM11/LM27) and arabinogalactan-protein (LM2) epitopes, and sandwich-ELISA evidence indicates that, in wheat particularly, these can be interlinked in multi-polysaccharide complexes. Using wheat as a model, exudate-binding monoclonal antibodies have enabled the tracking of polysaccharide release along root axes of young seedlings, and their presence at root hair surfaces and in rhizosheaths. The observations indicate that specific root exudate polysaccharides, distinct from cell wall polysaccharides, are adhesive factors secreted by root axes, and that they contribute to the formation and stabilisation of cereal rhizosheaths.
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Affiliation(s)
- Andrew F Galloway
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Jumana Akhtar
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Susan E Marcus
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Nathan Fletcher
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Katie Field
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Paul Knox
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
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13
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Ahl LI, Mravec J, Jørgensen B, Rudall PJ, Rønsted N, Grace OM. Dynamics of intracellular mannan and cell wall folding in the drought responses of succulent Aloe species. PLANT, CELL & ENVIRONMENT 2019; 42:2458-2471. [PMID: 30980422 PMCID: PMC6851777 DOI: 10.1111/pce.13560] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 05/17/2023]
Abstract
Plants have evolved a multitude of adaptations to survive extreme conditions. Succulent plants have the capacity to tolerate periodically dry environments, due to their ability to retain water in a specialized tissue, termed hydrenchyma. Cell wall polysaccharides are important components of water storage in hydrenchyma cells. However, the role of the cell wall and its polysaccharide composition in relation to drought resistance of succulent plants are unknown. We investigate the drought response of leaf-succulent Aloe (Asphodelaceae) species using a combination of histological microscopy, quantification of water content, and comprehensive microarray polymer profiling. We observed a previously unreported mode of polysaccharide and cell wall structural dynamics triggered by water shortage. Microscopical analysis of the hydrenchyma cell walls revealed highly regular folding patterns indicative of predetermined cell wall mechanics in the remobilization of stored water and the possible role of homogalacturonan in this process. The in situ distribution of mannans in distinct intracellular compartments during drought, for storage, and apparent upregulation of pectins, imparting flexibility to the cell wall, facilitate elaborate cell wall folding during drought stress. We conclude that cell wall polysaccharide composition plays an important role in water storage and drought response in Aloe.
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Affiliation(s)
- Louise Isager Ahl
- Natural History Museum of Denmark, Faculty of ScienceUniversity of CopenhagenCopenhagen KDK‐1353Denmark
| | - Jozef Mravec
- Department of Plant and Environmental Sciences, Faculty of ScienceUniversity of CopenhagenFrederiksberg CDK‐1871Denmark
| | - Bodil Jørgensen
- Department of Plant and Environmental Sciences, Faculty of ScienceUniversity of CopenhagenFrederiksberg CDK‐1871Denmark
| | - Paula J. Rudall
- Department of Comparative Plant and Fungal BiologyRoyal Botanic Gardens, KewRichmondTW9 3AEUK
| | - Nina Rønsted
- Natural History Museum of Denmark, Faculty of ScienceUniversity of CopenhagenCopenhagen KDK‐1353Denmark
| | - Olwen M. Grace
- Department of Comparative Plant and Fungal BiologyRoyal Botanic Gardens, KewRichmondTW9 3AEUK
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14
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Ahl LI, Al-Husseini N, Al-Helle S, Staerk D, Grace OM, Willats WGT, Mravec J, Jørgensen B, Rønsted N. Detection of Seasonal Variation in Aloe Polysaccharides Using Carbohydrate Detecting Microarrays. FRONTIERS IN PLANT SCIENCE 2019; 10:512. [PMID: 31139197 PMCID: PMC6527838 DOI: 10.3389/fpls.2019.00512] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 04/03/2019] [Indexed: 05/13/2023]
Abstract
Aloe vera gel is a globally popular natural product used for the treatment of skin conditions. Its useful properties are attributed to the presence of bioactive polysaccharides. Nearly 25% of the 600 species in the genus Aloe are used locally in traditional medicine, indicating that the bioactive components in Aloe vera may be common across the genus Aloe. The complexity of the polysaccharides has hindered development of relevant assays for authentication of Aloe products. Carbohydrate detecting microarrays have recently been suggested as a method for profiling Aloe polysaccharide composition. The aim of this study was to use carbohydrate detecting microarrays to investigate the seasonal variation in the polysaccharide composition of two medicinal and two non-medicinal Aloe species over the course of a year. Microscopy was used to explore where in the cells the bioactive polysaccharides are present and predict their functional role in the cell wall structure. The carbohydrate detecting microarrays analyses showed distinctive differences in the polysaccharide composition between the different species and carbohydrate detecting microarrays therefore has potential as a complementary screening method directly targeting the presence and composition of relevant polysaccharides. The results also show changes in the polysaccharide composition over the year within the investigated species, which may be of importance for commercial growing in optimizing harvest times to obtain higher yield of relevant polysaccharides.
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Affiliation(s)
- Louise Isager Ahl
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Narjes Al-Husseini
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Sara Al-Helle
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Dan Staerk
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Olwen M. Grace
- Comparative Plant and Fungal Biology, Royal Botanic Gardens Kew, Richmond, United Kingdom
| | - William G. T. Willats
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jozef Mravec
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Bodil Jørgensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Nina Rønsted
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
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15
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Iglesias-Fernández R, Pastor-Mora E, Vicente-Carbajosa J, Carbonero P. A Possible Role of the Aleurone Expressed Gene HvMAN1 in the Hydrolysis of the Cell Wall Mannans of the Starchy Endosperm in Germinating Hordeum vulgare L. Seeds. FRONTIERS IN PLANT SCIENCE 2019; 10:1706. [PMID: 32038680 PMCID: PMC6983769 DOI: 10.3389/fpls.2019.01706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/04/2019] [Indexed: 05/17/2023]
Abstract
The barley endo-β-mannanase (MAN) gene family (HvMAN1-6) has been identified and the expression of its members analyzed throughout different plant organs, and upon grain development and germination. The HvMAN1 gene has been found to be highly expressed in developing and germinating grains. The MAN (EC 3.2.1.78) enzymatic activity gets a maximum in grains at 48 h of germination (post-germination event). Immunolocalization of mannan polymers in grains has revealed the presence of these polysaccharides in the endosperm cell walls (CWs). By mRNA in situ hybridization assays, the HvMAN1 transcripts have been localized to the aleurone layer, but not to the dead starchy endosperm cells. These data suggest that MAN1 is synthesized in the aleurone layer during early grain imbibition and moves potentially through the apoplast to the endosperm where the hydrolysis of the mannan polymers takes place after germination sensu stricto. Hence, mannans in the starchy endosperm CWs, besides their structural function, could be used as reserve compounds upon barley post-germination.
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Affiliation(s)
- Raquel Iglesias-Fernández
- Centro de Biotecnología y Genómica de Plantas-Severo Ochoa (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Pozuelo de Alarcón, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Madrid, Spain
- *Correspondence: Raquel Iglesias-Fernández,
| | - Elena Pastor-Mora
- Centro de Biotecnología y Genómica de Plantas-Severo Ochoa (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Pozuelo de Alarcón, Spain
| | - Jesús Vicente-Carbajosa
- Centro de Biotecnología y Genómica de Plantas-Severo Ochoa (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Pozuelo de Alarcón, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Madrid, Spain
| | - Pilar Carbonero
- Centro de Biotecnología y Genómica de Plantas-Severo Ochoa (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Pozuelo de Alarcón, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Madrid, Spain
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16
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von Freiesleben P, Spodsberg N, Stenbæk A, Stålbrand H, Krogh KBRM, Meyer AS. Boosting of enzymatic softwood saccharification by fungal GH5 and GH26 endomannanases. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:194. [PMID: 30026809 PMCID: PMC6048861 DOI: 10.1186/s13068-018-1184-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 06/21/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Softwood is a promising feedstock for lignocellulosic biorefineries, but as it contains galactoglucomannan efficient mannan-degrading enzymes are required to unlock its full potential. RESULTS Boosting of the saccharification of pretreated softwood (Canadian lodgepole pine) was investigated for 10 fungal endo-β(1→4)-mannanases (endomannanases) from GH5 and GH26, including 6 novel GH26 enzymes. The endomannanases from Trichoderma reesei (TresMan5A) and Podospora anserina (PansMan26) were investigated with and without their carbohydrate-binding module (CBM). The pH optimum and initial rates of enzyme catalysed hydrolysis were determined on pure β-mannans, including acetylated and deacetylated spruce galactoglucomannan. Melting temperature (Tm) and stability of the endomannanases during prolonged incubations were also assessed. The highest initial rates on the pure mannans were attained by GH26 endomannanases. Acetylation tended to decrease the enzymatic rates to different extents depending on the enzyme. Despite exhibiting low rates on the pure mannan substrates, TresMan5A with CBM1 catalysed highest release among the endomannanases of both mannose and glucose during softwood saccharification. The presence of the CBM1 as well as the catalytic capability of the TresMan5A core module itself seemed to allow fast and more profound degradation of portions of the mannan that led to better cellulose degradation. In contrast, the presence of the CBM35 did not change the performance of PansMan26 in softwood saccharification. CONCLUSIONS This study identified TresMan5A as the best endomannanase for increasing cellulase catalysed glucose release from softwood. Except for the superior performance of TresMan5A, the fungal GH5 and GH26 endomannanases generally performed on par on the lignocellulosic matrix. The work also illustrated the importance of using genuine lignocellulosic substrates rather than simple model substrates when selecting enzymes for industrial biomass applications.
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Affiliation(s)
- Pernille von Freiesleben
- Novozymes A/S, Krogshøjvej 36, 2880 Bagsværd, Denmark
- Protein Chemistry & Enzyme Technology, DTU Bioengineering, Technical University of Denmark, Building 221, 2800 Kgs. Lyngby, Denmark
| | | | - Anne Stenbæk
- Novozymes A/S, Krogshøjvej 36, 2880 Bagsværd, Denmark
| | - Henrik Stålbrand
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, PO Box 124, 221 00 Lund, Sweden
| | | | - Anne S. Meyer
- Protein Chemistry & Enzyme Technology, DTU Bioengineering, Technical University of Denmark, Building 221, 2800 Kgs. Lyngby, Denmark
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17
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Carrillo-Barral N, Matilla AJ, Rodríguez-Gacio MDC, Iglesias-Fernández R. Mannans and endo-β-mannanase transcripts are located in different seed compartments during Brassicaceae germination. PLANTA 2018; 247:649-661. [PMID: 29164367 DOI: 10.1007/s00425-017-2815-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/15/2017] [Indexed: 05/28/2023]
Abstract
Mannans but not endo-β-mannanases are mainly found in the mucilage layer of two Brassicaceae seeds. Nonetheless, mannanase mobilization from inner to outer seed layers cannot be ruled out. The contribution of endo-β-mannanase (MAN) genes to the germination of the wild-type Sisymbrium officinale and cultivated Brassica rapa (Brassicaceae) species has been explored. In both species, mannans have been localized to the imbibed external seed coat layer (mucilage) by fluorescence immunolocalization and MAN enzymatic activity increases in seeds as imbibition progresses, reaching a peak before 100% germination is achieved. The MAN gene families have been annotated and the expression of their members analyzed in vegetative and reproductive organs. In S. officinale and B. rapa, MAN2, MAN5, MAN6, and MAN7 transcripts accumulate upon seed imbibition. SoMAN7 is the most expressed MAN gene in S. officinale germinating seeds, as occurs with its ortholog in Arabidopsis thaliana, but in B. rapa, the most abundant transcripts are BrMAN2 and BrMAN5. These genes (MAN2, MAN5, MAN6, and MAN7) are localized, by mRNA in situ hybridization, to the micropylar at the endosperm layer and to the radicle in S. officinale, but in B. rapa, these mRNAs are faintly found to the micropylar living seed coat layer and are mainly present at the radicle tip and the vascular bundles. If the domestication process undergone by B. rapa is responsible for these different MAN expression patterns, upon germination remains to be elucidated. Since mannans and MAN genes are not spatially distributed in the same seed tissues, a movement of MAN enzymes that are synthesized with typical signal peptides from the embryo tissues to the mucilage layer (via apoplastic space) is necessary for the mannans to be hydrolyzed.
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Affiliation(s)
- Néstor Carrillo-Barral
- Departamento de Fisiología Vegetal, Facultad de Farmacia, Universidad de Santiago de Compostela, 15780, Santiago de Compostela, Spain
| | - Angel J Matilla
- Departamento de Fisiología Vegetal, Facultad de Farmacia, Universidad de Santiago de Compostela, 15780, Santiago de Compostela, Spain
| | - María Del Carmen Rodríguez-Gacio
- Departamento de Fisiología Vegetal, Facultad de Farmacia, Universidad de Santiago de Compostela, 15780, Santiago de Compostela, Spain
| | - Raquel Iglesias-Fernández
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, 28223, Madrid, Spain.
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18
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Blake AD, Beri NR, Guttman HS, Cheng R, Gardner JG. The complex physiology of
Cellvibrio japonicus
xylan degradation relies on a single cytoplasmic β‐xylosidase for xylo‐oligosaccharide utilization. Mol Microbiol 2018; 107:610-622. [DOI: 10.1111/mmi.13903] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Andrew D. Blake
- Department of Biological SciencesUniversity of Maryland ‐ Baltimore CountyBaltimore Maryland USA
| | - Nina R. Beri
- Department of Biological SciencesUniversity of Maryland ‐ Baltimore CountyBaltimore Maryland USA
| | - Hadassa S. Guttman
- Department of Biological SciencesUniversity of Maryland ‐ Baltimore CountyBaltimore Maryland USA
| | - Raymond Cheng
- Department of Biological SciencesUniversity of Maryland ‐ Baltimore CountyBaltimore Maryland USA
| | - Jeffrey G. Gardner
- Department of Biological SciencesUniversity of Maryland ‐ Baltimore CountyBaltimore Maryland USA
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19
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Rydahl MG, Hansen AR, Kračun SK, Mravec J. Report on the Current Inventory of the Toolbox for Plant Cell Wall Analysis: Proteinaceous and Small Molecular Probes. FRONTIERS IN PLANT SCIENCE 2018; 9:581. [PMID: 29774041 PMCID: PMC5943554 DOI: 10.3389/fpls.2018.00581] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/13/2018] [Indexed: 05/18/2023]
Abstract
Plant cell walls are highly complex structures composed of diverse classes of polysaccharides, proteoglycans, and polyphenolics, which have numerous roles throughout the life of a plant. Significant research efforts aim to understand the biology of this cellular organelle and to facilitate cell-wall-based industrial applications. To accomplish this, researchers need to be provided with a variety of sensitive and specific detection methods for separate cell wall components, and their various molecular characteristics in vitro as well as in situ. Cell wall component-directed molecular detection probes (in short: cell wall probes, CWPs) are an essential asset to the plant glycobiology toolbox. To date, a relatively large set of CWPs has been produced-mainly consisting of monoclonal antibodies, carbohydrate-binding modules, synthetic antibodies produced by phage display, and small molecular probes. In this review, we summarize the state-of-the-art knowledge about these CWPs; their classification and their advantages and disadvantages in different applications. In particular, we elaborate on the recent advances in non-conventional approaches to the generation of novel CWPs, and identify the remaining gaps in terms of target recognition. This report also highlights the addition of new "compartments" to the probing toolbox, which is filled with novel chemical biology tools, such as metabolic labeling reagents and oligosaccharide conjugates. In the end, we also forecast future developments in this dynamic field.
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Affiliation(s)
- Maja G. Rydahl
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Aleksander R. Hansen
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Stjepan K. Kračun
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- GlycoSpot IVS, Frederiksberg, Denmark
| | - Jozef Mravec
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- *Correspondence: Jozef Mravec
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20
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Nelson CE, Attia MA, Rogowski A, Morland C, Brumer H, Gardner JG. Comprehensive functional characterization of the glycoside hydrolase family 3 enzymes from Cellvibrio japonicus reveals unique metabolic roles in biomass saccharification. Environ Microbiol 2017; 19:5025-5039. [PMID: 29052930 DOI: 10.1111/1462-2920.13959] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/27/2017] [Accepted: 10/08/2017] [Indexed: 12/16/2022]
Abstract
Lignocellulose degradation is central to the carbon cycle and renewable biotechnologies. The xyloglucan (XyG), β(1→3)/β(1→4) mixed-linkage glucan (MLG) and β(1→3) glucan components of lignocellulose represent significant carbohydrate energy sources for saprophytic microorganisms. The bacterium Cellvibrio japonicus has a robust capacity for plant polysaccharide degradation, due to a genome encoding a large contingent of Carbohydrate-Active enZymes (CAZymes), many of whose specific functions remain unknown. Using a comprehensive genetic and biochemical approach, we have delineated the physiological roles of the four C. japonicus glycoside hydrolase family 3 (GH3) members on diverse β-glucans. Despite high protein sequence similarity and partially overlapping activity profiles on disaccharides, these β-glucosidases are not functionally equivalent. Bgl3A has a major role in MLG and sophorose utilization, and supports β(1→3) glucan utilization, while Bgl3B underpins cellulose utilization and supports MLG utilization. Bgl3C drives β(1→3) glucan utilization. Finally, Bgl3D is the crucial β-glucosidase for XyG utilization. This study not only sheds the light on the metabolic machinery of C. japonicus, but also expands the repertoire of characterized CAZymes for future deployment in biotechnological applications. In particular, the precise functional analysis provided here serves as a reference for informed bioinformatics on the genomes of other Cellvibrio and related species.
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Affiliation(s)
- Cassandra E Nelson
- Department of Biological Sciences, University of Maryland, Baltimore County, MD, USA
| | - Mohamed A Attia
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada.,Department of Chemistry, University of British Columbia, Vancouver, Canada
| | - Artur Rogowski
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Carl Morland
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada.,Department of Chemistry, University of British Columbia, Vancouver, Canada.,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada.,Department of Botany, University of British Columbia, Vancouver, Canada
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland, Baltimore County, MD, USA
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21
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Wang Y, Shu T, Fan P, Zhang H, Turunen O, Xiong H, Yu L. Characterization of a recombinant alkaline thermostable β-mannanase and its application in eco-friendly ramie degumming. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.06.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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22
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Larsbrink J, Tuveng TR, Pope PB, Bulone V, Eijsink VG, Brumer H, McKee LS. Proteomic insights into mannan degradation and protein secretion by the forest floor bacterium Chitinophaga pinensis. J Proteomics 2017; 156:63-74. [DOI: 10.1016/j.jprot.2017.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/13/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
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23
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Nelson CE, Rogowski A, Morland C, Wilhide JA, Gilbert HJ, Gardner JG. Systems analysis in Cellvibrio japonicus resolves predicted redundancy of β-glucosidases and determines essential physiological functions. Mol Microbiol 2017; 104:294-305. [PMID: 28118504 DOI: 10.1111/mmi.13625] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2017] [Indexed: 12/29/2022]
Abstract
Degradation of polysaccharides forms an essential arc in the carbon cycle, provides a percentage of our daily caloric intake, and is a major driver in the renewable chemical industry. Microorganisms proficient at degrading insoluble polysaccharides possess large numbers of carbohydrate active enzymes (CAZymes), many of which have been categorized as functionally redundant. Here we present data that suggests that CAZymes that have overlapping enzymatic activities can have unique, non-overlapping biological functions in the cell. Our comprehensive study to understand cellodextrin utilization in the soil saprophyte Cellvibrio japonicus found that only one of four predicted β-glucosidases is required in a physiological context. Gene deletion analysis indicated that only the cel3B gene product is essential for efficient cellodextrin utilization in C. japonicus and is constitutively expressed at high levels. Interestingly, expression of individual β-glucosidases in Escherichia coli K-12 enabled this non-cellulolytic bacterium to be fully capable of using cellobiose as a sole carbon source. Furthermore, enzyme kinetic studies indicated that the Cel3A enzyme is significantly more active than the Cel3B enzyme on the oligosaccharides but not disaccharides. Our approach for parsing related CAZymes to determine actual physiological roles in the cell can be applied to other polysaccharide-degradation systems.
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Affiliation(s)
- Cassandra E Nelson
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, Maryland, USA
| | - Artur Rogowski
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Carl Morland
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Joshua A Wilhide
- Molecular Characterization and Analysis Complex, University of Maryland - Baltimore County, Maryland, USA
| | - Harry J Gilbert
- Molecular Characterization and Analysis Complex, University of Maryland - Baltimore County, Maryland, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, Maryland, USA
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24
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Walker JA, Pattathil S, Bergeman LF, Beebe ET, Deng K, Mirzai M, Northen TR, Hahn MG, Fox BG. Determination of glycoside hydrolase specificities during hydrolysis of plant cell walls using glycome profiling. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:31. [PMID: 28184246 PMCID: PMC5288845 DOI: 10.1186/s13068-017-0703-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/06/2017] [Indexed: 05/29/2023]
Abstract
BACKGROUND Glycoside hydrolases (GHs) are enzymes that hydrolyze polysaccharides into simple sugars. To better understand the specificity of enzyme hydrolysis within the complex matrix of polysaccharides found in the plant cell wall, we studied the reactions of individual enzymes using glycome profiling, where a comprehensive collection of cell wall glycan-directed monoclonal antibodies are used to detect polysaccharide epitopes remaining in the walls after enzyme treatment and quantitative nanostructure initiator mass spectrometry (oxime-NIMS) to determine soluble sugar products of their reactions. RESULTS Single, purified enzymes from the GH5_4, GH10, and GH11 families of glycoside hydrolases hydrolyzed hemicelluloses as evidenced by the loss of specific epitopes from the glycome profiles in enzyme-treated plant biomass. The glycome profiling data were further substantiated by oxime-NIMS, which identified hexose products from hydrolysis of cellulose, and pentose-only and mixed hexose-pentose products from the hydrolysis of hemicelluloses. The GH10 enzyme proved to be reactive with the broadest diversity of xylose-backbone polysaccharide epitopes, but was incapable of reacting with glucose-backbone polysaccharides. In contrast, the GH5 and GH11 enzymes studied here showed the ability to react with both glucose- and xylose-backbone polysaccharides. CONCLUSIONS The identification of enzyme specificity for a wide diversity of polysaccharide structures provided by glycome profiling, and the correlated identification of soluble oligosaccharide hydrolysis products provided by oxime-NIMS, offers a unique combination to understand the hydrolytic capabilities and constraints of individual enzymes as they interact with plant biomass.
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Affiliation(s)
- Johnnie A. Walker
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Sivakumar Pattathil
- US Department of Energy Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Lai F. Bergeman
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Emily T. Beebe
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Kai Deng
- US Department of Energy Joint Bioenergy Institute, Emeryville, CA 94608 USA
- Sandia National Laboratories, Livermore, CA 94551 USA
| | - Maryam Mirzai
- US Department of Energy Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Trent R. Northen
- US Department of Energy Joint Bioenergy Institute, Emeryville, CA 94608 USA
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Michael G. Hahn
- US Department of Energy Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Brian G. Fox
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
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Djajadi DT, Hansen AR, Jensen A, Thygesen LG, Pinelo M, Meyer AS, Jørgensen H. Surface properties correlate to the digestibility of hydrothermally pretreated lignocellulosic Poaceae biomass feedstocks. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:49. [PMID: 28250817 PMCID: PMC5322652 DOI: 10.1186/s13068-017-0730-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 02/10/2017] [Indexed: 05/08/2023]
Abstract
BACKGROUND Understanding factors that govern lignocellulosic biomass recalcitrance is a prerequisite for designing efficient 2nd generation biorefining processes. However, the reasons and mechanisms responsible for quantitative differences in enzymatic digestibility of various biomass feedstocks in response to hydrothermal pretreatment at different severities are still not sufficiently understood. RESULTS Potentially important lignocellulosic feedstocks for biorefining, corn stover (Zea mays subsp. mays L.), stalks of Miscanthus × giganteus, and wheat straw (Triticum aestivum L.) were systematically hydrothermally pretreated; each at three different severities of 3.65, 3.83, and 3.97, respectively, and the enzymatic digestibility was assessed. Pretreated samples of Miscanthus × giganteus stalks were the least digestible among the biomass feedstocks producing ~24 to 66.6% lower glucose yields than the other feedstocks depending on pretreatment severity and enzyme dosage. Bulk biomass composition analyses, 2D nuclear magnetic resonance, and comprehensive microarray polymer profiling were not able to explain the observed differences in recalcitrance among the pretreated feedstocks. However, methods characterizing physical and chemical features of the biomass surfaces, specifically contact angle measurements (wettability) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy (surface biopolymer composition) produced data correlating pretreatment severity and enzymatic digestibility, and they also revealed differences that correlated to enzymatic glucose yield responses among the three different biomass types. CONCLUSION The study revealed that to a large extent, factors related to physico-chemical surface properties, namely surface wettability as assessed by contact angle measurements and surface content of hemicellulose, lignin, and wax as assessed by ATR-FTIR rather than bulk biomass chemical composition correlated to the recalcitrance of the tested biomass types. The data provide new insight into how hydrothermal pretreatment severity affects surface properties of key Poaceae lignocellulosic biomass and may help design new approaches to overcome biomass recalcitrance.
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Affiliation(s)
- Demi T. Djajadi
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| | - Aleksander R. Hansen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Kongens Lyngby, Denmark
| | - Anders Jensen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - Lisbeth G. Thygesen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - Manuel Pinelo
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| | - Anne S. Meyer
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| | - Henning Jørgensen
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Kongens Lyngby, Denmark
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Production, properties, and applications of endo-β-mannanases. Biotechnol Adv 2017; 35:1-19. [DOI: 10.1016/j.biotechadv.2016.11.001] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 10/12/2016] [Accepted: 11/07/2016] [Indexed: 12/27/2022]
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Verhertbruggen Y, Walker JL, Guillon F, Scheller HV. A Comparative Study of Sample Preparation for Staining and Immunodetection of Plant Cell Walls by Light Microscopy. FRONTIERS IN PLANT SCIENCE 2017; 8:1505. [PMID: 28900439 PMCID: PMC5581911 DOI: 10.3389/fpls.2017.01505] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 08/14/2017] [Indexed: 05/02/2023]
Abstract
Staining and immunodetection by light microscopy are methods widely used to investigate plant cell walls. The two techniques have been crucial to study the cell wall architecture in planta, its deconstruction by chemicals or cell wall-degrading enzymes. They have been instrumental in detecting the presence of cell types, in deciphering plant cell wall evolution and in characterizing plant mutants and transformants. The success of immunolabeling relies on how plant materials are embedded and sectioned. Agarose coating, wax and resin embedding are, respectively, associated with vibratome, microtome and ultramicrotome sectioning. Here, we have systematically carried out a comparative analysis of these three methods of sample preparation when they are applied for cell wall staining and cell wall immunomicroscopy. In order to help the plant community in understanding and selecting adequate methods of embedding and sectioning for cell wall immunodetection, we review in this article the advantages and limitations of these three methods. Moreover, we offer detailed protocols of embedding for studying plant materials through microscopy.
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Affiliation(s)
- Yves Verhertbruggen
- Joint BioEnergy Institute, Lawrence Berkeley National LaboratoryEmeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National LaboratoryBerkeley, CA, United States
- Institut National de la Recherche Agronomique, UR 1268Nantes, France
- *Correspondence: Yves Verhertbruggen
| | - Jesse L. Walker
- Joint BioEnergy Institute, Lawrence Berkeley National LaboratoryEmeryville, CA, United States
- Department of Plant and Microbial Biology, University of California, BerkeleyBerkeley, CA, United States
| | - Fabienne Guillon
- Institut National de la Recherche Agronomique, UR 1268Nantes, France
| | - Henrik V. Scheller
- Joint BioEnergy Institute, Lawrence Berkeley National LaboratoryEmeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National LaboratoryBerkeley, CA, United States
- Department of Plant and Microbial Biology, University of California, BerkeleyBerkeley, CA, United States
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Ladevèze S, Laville E, Despres J, Mosoni P, Potocki-Véronèse G. Mannoside recognition and degradation by bacteria. Biol Rev Camb Philos Soc 2016; 92:1969-1990. [PMID: 27995767 DOI: 10.1111/brv.12316] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/01/2016] [Accepted: 11/11/2016] [Indexed: 11/29/2022]
Abstract
Mannosides constitute a vast group of glycans widely distributed in nature. Produced by almost all organisms, these carbohydrates are involved in numerous cellular processes, such as cell structuration, protein maturation and signalling, mediation of protein-protein interactions and cell recognition. The ubiquitous presence of mannosides in the environment means they are a reliable source of carbon and energy for bacteria, which have developed complex strategies to harvest them. This review focuses on the various mannosides that can be found in nature and details their structure. It underlines their involvement in cellular interactions and finally describes the latest discoveries regarding the catalytic machinery and metabolic pathways that bacteria have developed to metabolize them.
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Affiliation(s)
- Simon Ladevèze
- LISBP, Université de Toulouse, CNRS, INRA, INSA, 31077, Toulouse, France
| | - Elisabeth Laville
- LISBP, Université de Toulouse, CNRS, INRA, INSA, 31077, Toulouse, France
| | - Jordane Despres
- INRA, UR454 Microbiologie, F-63122, Saint-Genès Champanelle, France
| | - Pascale Mosoni
- INRA, UR454 Microbiologie, F-63122, Saint-Genès Champanelle, France
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29
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Nelson CE, Beri NR, Gardner JG. Custom fabrication of biomass containment devices using 3-D printing enables bacterial growth analyses with complex insoluble substrates. J Microbiol Methods 2016; 130:136-143. [DOI: 10.1016/j.mimet.2016.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 09/19/2016] [Accepted: 09/19/2016] [Indexed: 10/21/2022]
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30
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Gardner JG. Polysaccharide degradation systems of the saprophytic bacterium Cellvibrio japonicus. World J Microbiol Biotechnol 2016; 32:121. [PMID: 27263016 DOI: 10.1007/s11274-016-2068-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 04/07/2016] [Indexed: 01/10/2023]
Abstract
Study of recalcitrant polysaccharide degradation by bacterial systems is critical for understanding biological processes such as global carbon cycling, nutritional contributions of the human gut microbiome, and the production of renewable fuels and chemicals. One bacterium that has a robust ability to degrade polysaccharides is the Gram-negative saprophyte Cellvibrio japonicus. A bacterium with a circuitous history, C. japonicus underwent several taxonomy changes from an initially described Pseudomonas sp. Most of the enzymes described in the pre-genomics era have also been renamed. This review aims to consolidate the biochemical, structural, and genetic data published on C. japonicus and its remarkable ability to degrade cellulose, xylan, and pectin substrates. Initially, C. japonicus carbohydrate-active enzymes were studied biochemically and structurally for their novel polysaccharide binding and degradation characteristics, while more recent systems biology approaches have begun to unravel the complex regulation required for lignocellulose degradation in an environmental context. Also included is a discussion for the future of C. japonicus as a model system, with emphasis on current areas unexplored in terms of polysaccharide degradation and emerging directions for C. japonicus in both environmental and biotechnological applications.
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Affiliation(s)
- Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA.
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31
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Katsimpouras C, Dimarogona M, Petropoulos P, Christakopoulos P, Topakas E. A thermostable GH26 endo-β-mannanase from Myceliophthora thermophila capable of enhancing lignocellulose degradation. Appl Microbiol Biotechnol 2016; 100:8385-97. [PMID: 27193267 DOI: 10.1007/s00253-016-7609-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 04/24/2016] [Accepted: 05/01/2016] [Indexed: 10/21/2022]
Abstract
The endomannanase gene em26a from the thermophilic fungus Myceliophthora thermophila, belonging to the glycoside hydrolase family 26, was functionally expressed in the methylotrophic yeast Pichia pastoris. The putative endomannanase, dubbed MtMan26A, was purified to homogeneity (60 kDa) and subsequently characterized. The optimum pH and temperature for the enzymatic activity of MtMan26A were 6.0 and 60 °C, respectively. MtMan26A showed high specific activity against konjac glucomannan and carob galactomannan, while it also exhibited high thermal stability with a half-life of 14.4 h at 60 °C. Thermostability is of great importance, especially in industrial processes where harsh conditions are employed. With the aim of better understanding its structure-function relationships, a homology model of MtMan26A was constructed, based on the crystallographic structure of a close homologue. Finally, the addition of MtMan26A as a supplement to the commercial enzyme mixture Celluclast® 1.5 L and Novozyme® 188 resulted in enhanced enzymatic hydrolysis of pretreated beechwood sawdust, improving the release of total reducing sugars and glucose by 13 and 12 %, respectively.
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Affiliation(s)
- Constantinos Katsimpouras
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece
| | - Maria Dimarogona
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece
| | - Pericles Petropoulos
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece
| | - Paul Christakopoulos
- Biochemical and Chemical Process Engineering, Division of Sustainable Process Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-97187, Luleå, Sweden
| | - Evangelos Topakas
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece.
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32
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Crouch LI, Labourel A, Walton PH, Davies GJ, Gilbert HJ. The Contribution of Non-catalytic Carbohydrate Binding Modules to the Activity of Lytic Polysaccharide Monooxygenases. J Biol Chem 2016; 291:7439-49. [PMID: 26801613 PMCID: PMC4817175 DOI: 10.1074/jbc.m115.702365] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Indexed: 01/23/2023] Open
Abstract
Lignocellulosic biomass is a sustainable industrial substrate. Copper-dependent lytic polysaccharide monooxygenases (LPMOs) contribute to the degradation of lignocellulose and increase the efficiency of biofuel production. LPMOs can contain non-catalytic carbohydrate binding modules (CBMs), but their role in the activity of these enzymes is poorly understood. Here we explored the importance of CBMs in LPMO function. The family 2a CBMs of two monooxygenases,CfLPMO10 andTbLPMO10 fromCellulomonas fimiandThermobispora bispora, respectively, were deleted and/or replaced with CBMs from other proteins. The data showed that the CBMs could potentiate and, surprisingly, inhibit LPMO activity, and that these effects were both enzyme-specific and substrate-specific. Removing the natural CBM or introducingCtCBM3a, from theClostridium thermocellumcellulosome scaffoldin CipA, almost abolished the catalytic activity of the LPMOs against the cellulosic substrates. The deleterious effect of CBM removal likely reflects the importance of prolonged presentation of the enzyme on the surface of the substrate for efficient catalytic activity, as only LPMOs appended to CBMs bound tightly to cellulose. The negative impact ofCtCBM3a is in sharp contrast with the capacity of this binding module to potentiate the activity of a range of glycoside hydrolases including cellulases. The deletion of the endogenous CBM fromCfLPMO10 or the introduction of a family 10 CBM fromCellvibrio japonicusLPMO10B intoTbLPMO10 influenced the quantity of non-oxidized products generated, demonstrating that CBMs can modulate the mode of action of LPMOs. This study demonstrates that engineered LPMO-CBM hybrids can display enhanced industrially relevant oxygenations.
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Affiliation(s)
- Lucy I Crouch
- From the Institute for Cell and Molecular Biosciences, The Medical School Newcastle University, Newcastle upon Tyne NE2 4HH and
| | - Aurore Labourel
- From the Institute for Cell and Molecular Biosciences, The Medical School Newcastle University, Newcastle upon Tyne NE2 4HH and
| | - Paul H Walton
- the York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Gideon J Davies
- the York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Harry J Gilbert
- From the Institute for Cell and Molecular Biosciences, The Medical School Newcastle University, Newcastle upon Tyne NE2 4HH and
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von Freiesleben P, Spodsberg N, Blicher TH, Anderson L, Jørgensen H, Stålbrand H, Meyer AS, Krogh KBRM. An Aspergillus nidulans GH26 endo-β-mannanase with a novel degradation pattern on highly substituted galactomannans. Enzyme Microb Technol 2015; 83:68-77. [PMID: 26777252 DOI: 10.1016/j.enzmictec.2015.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/04/2015] [Accepted: 10/31/2015] [Indexed: 01/17/2023]
Abstract
The activity and substrate degradation pattern of a novel Aspergillus nidulans GH26 endo-β-mannanase (AnMan26A) was investigated using two galactomannan substrates with varying amounts of galactopyranosyl residues. The AnMan26A was characterized in parallel with the GH26 endomannanase from Podospora anserina (PaMan26A) and three GH5 endomannanases from A. nidulans and Trichoderma reesei (AnMan5A, AnMan5C and TrMan5A). The initial rates and the maximal degree of enzymatically catalyzed conversion of locust bean gum and guar gum galactomannans were determined. The hydrolysis product profile at maximal degree of conversion was determined using DNA sequencer-Assisted Saccharide analysis in High throughput (DASH). This is the first reported use of this method for analyzing galactomannooligosaccharides. AnMan26A and PaMan26A were found to have a novel substrate degradation pattern on the two galactomannan substrates. On the highly substituted guar gum AnMan26A and PaMan26A reached 35-40% as their maximal degree of conversion whereas the three tested GH5 endomannanases only reached 8-10% as their maximal degree of conversion. α-Galactosyl-mannose was identified as the dominant degradation product resulting from AnMan26A and PaMan26A action on guar gum, strongly indicating that these two enzymes can accommodate galactopyranosyl residues in the -1 and in the +1 subsite. The degradation of α-6(4)-6(3)-di-galactosyl-mannopentaose by AnMan26A revealed accommodation of galactopyranosyl residues in the -2, -1 and +1 subsite of the enzyme. Accommodation of galactopyranosyl residues in subsites -2 and +1 has not been observed for other characterized endomannanases to date. Docking analysis of galactomannooligosaccharides in available crystal structures and homology models supported the conclusions drawn from the experimental results. This newly discovered diversity of substrate degradation patterns demonstrates an expanded functionality of fungal endomannanases, than hitherto reported.
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Affiliation(s)
- Pernille von Freiesleben
- Novozymes A/S, Krogshøjvej 36, 2880 Bagsværd, Denmark; Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Building 229, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | | | | | - Lars Anderson
- Novozymes A/S, Krogshøjvej 36, 2880 Bagsværd, Denmark
| | - Henning Jørgensen
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Building 229, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Henrik Stålbrand
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, PO Box 124, SE-221 00 Lund, Sweden
| | - Anne S Meyer
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Building 229, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
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Pattathil S, Avci U, Zhang T, Cardenas CL, Hahn MG. Immunological Approaches to Biomass Characterization and Utilization. Front Bioeng Biotechnol 2015; 3:173. [PMID: 26579515 PMCID: PMC4623462 DOI: 10.3389/fbioe.2015.00173] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 10/12/2015] [Indexed: 11/13/2022] Open
Abstract
Plant biomass is the major renewable feedstock resource for sustainable generation of alternative transportation fuels to replace fossil carbon-derived fuels. Lignocellulosic cell walls are the principal component of plant biomass. Hence, a detailed understanding of plant cell wall structure and biosynthesis is an important aspect of bioenergy research. Cell walls are dynamic in their composition and structure, varying considerably among different organs, cells, and developmental stages of plants. Hence, tools are needed that are highly efficient and broadly applicable at various levels of plant biomass-based bioenergy research. The use of plant cell wall glycan-directed probes has seen increasing use over the past decade as an excellent approach for the detailed characterization of cell walls. Large collections of such probes directed against most major cell wall glycans are currently available worldwide. The largest and most diverse set of such probes consists of cell wall glycan-directed monoclonal antibodies (McAbs). These McAbs can be used as immunological probes to comprehensively monitor the overall presence, extractability, and distribution patterns among cell types of most major cell wall glycan epitopes using two mutually complementary immunological approaches, glycome profiling (an in vitro platform) and immunolocalization (an in situ platform). Significant progress has been made recently in the overall understanding of plant biomass structure, composition, and modifications with the application of these immunological approaches. This review focuses on such advances made in plant biomass analyses across diverse areas of bioenergy research.
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Affiliation(s)
- Sivakumar Pattathil
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Oak Ridge National Laboratory, BioEnergy Science Center (BESC), Oak Ridge, TN, USA
| | - Utku Avci
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Oak Ridge National Laboratory, BioEnergy Science Center (BESC), Oak Ridge, TN, USA
| | - Tiantian Zhang
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Claudia L. Cardenas
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Michael G. Hahn
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Oak Ridge National Laboratory, BioEnergy Science Center (BESC), Oak Ridge, TN, USA
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Kumagai Y, Yamashita K, Tagami T, Uraji M, Wan K, Okuyama M, Yao M, Kimura A, Hatanaka T. The loop structure of Actinomycete glycoside hydrolase family 5 mannanases governs substrate recognition. FEBS J 2015; 282:4001-14. [PMID: 26257335 DOI: 10.1111/febs.13401] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 07/23/2015] [Accepted: 08/05/2015] [Indexed: 02/01/2023]
Abstract
Endo-β-1,4-mannanases from Streptomyces thermolilacinus (StMan) and Thermobifida fusca (TfMan) demonstrated different substrate specificities. StMan hydrolyzed galactosylmannooligosaccharide (GGM5; 6(III) ,6(IV) -α-d-galactosyl mannopentaose) to GGM3 and M2, whereas TfMan hydrolyzed GGM5 to GGM4 and M1. To determine the region involved in the substrate specificity, we constructed chimeric enzymes of StMan and TfMan and evaluated their substrate specificities. Moreover, the crystal structure of the catalytic domain of StMan (StMandC) and the complex structure of the inactive mutant StE273AdC with M6 were solved at resolutions of 1.60 and 1.50 Å, respectively. Structural comparisons of StMandC and the catalytic domain of TfMan lead to the identification of a subsite around -1 in StMandC that could accommodate a galactose branch. These findings demonstrate that the two loops (loop7 and loop8) are responsible for substrate recognition in GH5 actinomycete mannanases. In particular, Trp281 in loop7 of StMan, which is located in a narrow and deep cleft, plays an important role in its affinity toward linear substrates. Asp310 in loop8 of StMan specifically bound to the galactosyl unit in the -1 subsite.
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Affiliation(s)
- Yuya Kumagai
- Okayama Prefectural Technology Center for Agriculture, Forestry and Fisheries, Research Institute for Biological Sciences (RIBS), Okayama, Japan.,Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Keitaro Yamashita
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Takayoshi Tagami
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Misugi Uraji
- Okayama Prefectural Technology Center for Agriculture, Forestry and Fisheries, Research Institute for Biological Sciences (RIBS), Okayama, Japan
| | - Kun Wan
- Okayama Prefectural Technology Center for Agriculture, Forestry and Fisheries, Research Institute for Biological Sciences (RIBS), Okayama, Japan
| | - Masayuki Okuyama
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Min Yao
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan.,Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Atsuo Kimura
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Tadashi Hatanaka
- Okayama Prefectural Technology Center for Agriculture, Forestry and Fisheries, Research Institute for Biological Sciences (RIBS), Okayama, Japan
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36
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Yamabhai M, Sak-Ubol S, Srila W, Haltrich D. Mannan biotechnology: from biofuels to health. Crit Rev Biotechnol 2015; 36:32-42. [DOI: 10.3109/07388551.2014.923372] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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In-Frame Deletions Allow Functional Characterization of Complex Cellulose Degradation Phenotypes in Cellvibrio japonicus. Appl Environ Microbiol 2015; 81:5968-75. [PMID: 26116676 DOI: 10.1128/aem.00847-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 06/16/2015] [Indexed: 12/31/2022] Open
Abstract
The depolymerization of the recalcitrant polysaccharides found in lignocellulose has become an area of intense interest due to the role of this process in global carbon cycling, human gut microbiome nutritional contributions, and bioenergy production. However, underdeveloped genetic tools have hampered study of bacterial lignocellulose degradation, especially outside model organisms. In this report, we describe an in-frame deletion strategy for the Gram-negative lignocellulose-degrading bacterium Cellvibrio japonicus. This method leverages optimized growth conditions for conjugation and sacB counterselection for the generation of markerless in-frame deletions. This method produces mutants in as few as 8 days and allows for the ability to make multiple gene deletions per strain. It is also possible to remove large sections of the genome, as shown in this report with the deletion of the nine-gene (9.4-kb) gsp operon in C. japonicus. We applied this system to study the complex phenotypes of cellulose degradation in C. japonicus. Our data indicated that a Δcel5B Δcel6A double mutant is crippled for cellulose utilization, more so than by either single mutation alone. Additionally, we deleted individual genes in the two-gene cbp2ED operon and showed that both genes contribute to cellulose degradation in C. japonicus. Overall, these described techniques substantially enhance the utility of C. japonicus as a model system to study lignocellulose degradation.
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Zhang M, Chen GX, Lv DW, Li XH, Yan YM. N-linked glycoproteome profiling of seedling leaf in Brachypodium distachyon L. J Proteome Res 2015; 14:1727-38. [PMID: 25652041 DOI: 10.1021/pr501080r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Brachypodium distachyon L., a model plant for cereal crops, has become important as an alternative and potential biofuel grass. In plants, N-glycosylation is one of the most common and important protein modifications, playing important roles in signal recognition, increase in protein activity, stability of protein structure, and formation of tissues and organs. In this study, we performed the first glycoproteome analysis in the seedling leaves of B. distachyon. Using lectin affinity chromatography enrichment and mass-spectrometry-based analysis, we identified 47 glycosylation sites representing 46 N-linked glycoproteins. Motif-X analysis showed that two conserved motifs, N-X-T/S (X is any amino acid, except Pro), were significantly enriched. Further functional analysis suggested that some of these identified glycoproteins are involved in signal transduction, protein trafficking, and quality control and the modification and remodeling of cell-wall components such as receptor-like kinases, protein disulfide isomerase, and polygalacturonase. Moreover, transmembrane helices and signal peptide prediction showed that most of these glycoproteins could participate in typical protein secretory pathways in eukaryotes. The results provide a general overview of protein N-glycosylation modifications during the early growth of seedling leaves in B. distachyon and supplement the glycoproteome databases of plants.
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Affiliation(s)
- Ming Zhang
- †College of Life Science, Capital Normal University, Xisanhuan Beilu No. 105, 100048 Beijing, China.,‡College of Life Science, Heze University, University Road No. 2269, 274015 Shandong, China
| | - Guan-Xing Chen
- †College of Life Science, Capital Normal University, Xisanhuan Beilu No. 105, 100048 Beijing, China
| | - Dong-Wen Lv
- †College of Life Science, Capital Normal University, Xisanhuan Beilu No. 105, 100048 Beijing, China
| | - Xiao-Hui Li
- †College of Life Science, Capital Normal University, Xisanhuan Beilu No. 105, 100048 Beijing, China
| | - Yue-Ming Yan
- †College of Life Science, Capital Normal University, Xisanhuan Beilu No. 105, 100048 Beijing, China.,§Hubei Collaborative Innovation Center for Grain Industry, Jing Secret Road No. 88, 434025 Jingzhou, China
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A polysaccharide utilization locus from an uncultured bacteroidetes phylotype suggests ecological adaptation and substrate versatility. Appl Environ Microbiol 2014; 81:187-95. [PMID: 25326301 DOI: 10.1128/aem.02858-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent metagenomic analyses have identified uncultured bacteria that are abundant in the rumen of herbivores and that possess putative biomass-converting enzyme systems. Here we investigate the saccharolytic capabilities of a polysaccharide utilization locus (PUL) that has been reconstructed from an uncultured Bacteroidetes phylotype (SRM-1) that dominates the rumen microbiome of Arctic reindeer. Characterization of the three PUL-encoded outer membrane glycoside hydrolases was performed using chromogenic substrates for initial screening, followed by detailed analyses of products generated from selected substrates, using high-pressure anion-exchange chromatography with electrochemical detection. Two glycoside hydrolase family 5 (GH5) endoglucanases (GH5_g and GH5_h) demonstrated activity against β-glucans, xylans, and xyloglucan, whereas GH5_h and the third enzyme, GH26_i, were active on several mannan substrates. Synergy experiments examining different combinations of the three enzymes demonstrated limited activity enhancement on individual substrates. Binding analysis of a SusE-positioned lipoprotein revealed an affinity toward β-glucans and, to a lesser extent, mannan, but unlike the two SusD-like lipoproteins previously characterized from the same PUL, binding to cellulose was not observed. Overall, these activities and binding specificities correlated well with the glycan content of the reindeer rumen, which was determined using comprehensive microarray polymer profiling and showed an abundance of various hemicellulose glycans. The substrate versatility of this single PUL putatively expands our perceptions regarding PUL machineries, which so far have demonstrated gene organization that suggests one cognate PUL for each substrate type. The presence of a PUL that possesses saccharolytic activity against a mixture of abundantly available polysaccharides supports the dominance of SRM-1 in the Svalbard reindeer rumen microbiome.
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Larsbrink J, Thompson AJ, Lundqvist M, Gardner JG, Davies GJ, Brumer H. A complex gene locus enables xyloglucan utilization in the model saprophyte Cellvibrio japonicus. Mol Microbiol 2014; 94:418-33. [PMID: 25171165 PMCID: PMC4285296 DOI: 10.1111/mmi.12776] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2014] [Indexed: 12/17/2022]
Abstract
The degradation of plant biomass by saprophytes is an ecologically important part of the global carbon cycle, which has also inspired a vast diversity of industrial enzyme applications. The xyloglucans (XyGs) constitute a family of ubiquitous and abundant plant cell wall polysaccharides, yet the enzymology of XyG saccharification is poorly studied. Here, we present the identification and molecular characterization of a complex genetic locus that is required for xyloglucan utilization by the model saprophyte Cellvibrio japonicus. In harness, transcriptomics, reverse genetics, enzyme kinetics, and structural biology indicate that the encoded cohort of an α-xylosidase, a β-galactosidase, and an α-l-fucosidase is specifically adapted for efficient, concerted saccharification of dicot (fucogalacto)xyloglucan oligosaccharides following import into the periplasm via an associated TonB-dependent receptor. The data support a biological model of xyloglucan degradation by C. japonicus with striking similarities – and notable differences – to the complex polysaccharide utilization loci of the Bacteroidetes.
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Affiliation(s)
- Johan Larsbrink
- Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, 106 91, Stockholm, Sweden
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Yu L, Shi D, Li J, Kong Y, Yu Y, Chai G, Hu R, Wang J, Hahn MG, Zhou G. CELLULOSE SYNTHASE-LIKE A2, a glucomannan synthase, is involved in maintaining adherent mucilage structure in Arabidopsis seed. PLANT PHYSIOLOGY 2014; 164:1842-56. [PMID: 24569843 PMCID: PMC3982747 DOI: 10.1104/pp.114.236596] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 02/24/2014] [Indexed: 05/17/2023]
Abstract
Mannans are hemicellulosic polysaccharides that are considered to have both structural and storage functions in the plant cell wall. However, it is not yet known how mannans function in Arabidopsis (Arabidopsis thaliana) seed mucilage. In this study, CELLULOSE SYNTHASE-LIKE A2 (CSLA2; At5g22740) expression was observed in several seed tissues, including the epidermal cells of developing seed coats. Disruption of CSLA2 resulted in thinner adherent mucilage halos, although the total amount of the adherent mucilage did not change compared with the wild type. This suggested that the adherent mucilage in the mutant was more compact compared with that of the wild type. In accordance with the role of CSLA2 in glucomannan synthesis, csla2-1 mucilage contained 30% less mannosyl and glucosyl content than did the wild type. No appreciable changes in the composition, structure, or macromolecular properties were observed for nonmannan polysaccharides in mutant mucilage. Biochemical analysis revealed that cellulose crystallinity was substantially reduced in csla2-1 mucilage; this was supported by the removal of most mucilage cellulose through treatment of csla2-1 seeds with endo-β-glucanase. Mutation in CSLA2 also resulted in altered spatial distribution of cellulose and an absence of birefringent cellulose microfibrils within the adherent mucilage. As with the observed changes in crystalline cellulose, the spatial distribution of pectin was also modified in csla2-1 mucilage. Taken together, our results demonstrate that glucomannans synthesized by CSLA2 are involved in modulating the structure of adherent mucilage, potentially through altering cellulose organization and crystallization.
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