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Pentari C, Kosinas C, Nikolaivits E, Dimarogona M, Topakas E. Structural and molecular insights into a bifunctional glycoside hydrolase 30 xylanase specific to glucuronoxylan. Biotechnol Bioeng 2024; 121:2067-2078. [PMID: 38678481 DOI: 10.1002/bit.28731] [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: 02/20/2024] [Revised: 04/15/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024]
Abstract
Glycoside hydrolase (GH) 30 family xylanases are enzymes of biotechnological interest due to their capacity to degrade recalcitrant hemicelluloses, such as glucuronoxylan (GX). This study focuses on a subfamily 7 GH30, TtXyn30A from Thermothelomyces thermophilus, which acts on GX in an "endo" and "exo" mode, releasing methyl-glucuronic acid branched xylooligosaccharides (XOs) and xylobiose, respectively. The crystal structure of inactive TtXyn30A in complex with 23-(4-O-methyl-α-D-glucuronosyl)-xylotriose (UXX), along with biochemical analyses, corroborate the implication of E233, previously identified as alternative catalytic residue, in the hydrolysis of decorated xylan. At the -1 subsite, the xylose adopts a distorted conformation, indicative of the Michaelis complex of TtXyn30AEE with UXX trapped in the semi-functional active site. The most significant structural rearrangements upon substrate binding are observed at residues W127 and E233. The structures with neutral XOs, representing the "exo" function, clearly show the nonspecific binding at aglycon subsites, contrary to glycon sites, where the xylose molecules are accommodated via multiple interactions. Last, an unproductive ligand binding site is found at the interface between the catalytic and the secondary β-domain which is present in all GH30 enzymes. These findings improve current understanding of the mechanism of bifunctional GH30s, with potential applications in the field of enzyme engineering.
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Affiliation(s)
- Christina Pentari
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Christos Kosinas
- Laboratory of Structural Biology and Biotechnology, Department of Chemical Engineering, University of Patras, Patras, Greece
| | - Efstratios Nikolaivits
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Maria Dimarogona
- Laboratory of Structural Biology and Biotechnology, Department of Chemical Engineering, University of Patras, Patras, Greece
| | - Evangelos Topakas
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
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St John FJ, Bynum L, Tauscheck DA, Crooks C. Use of xylosidase 3C from Segatella baroniae to discriminate xylan non-reducing terminus substitution characteristics. BMC Res Notes 2024; 17:175. [PMID: 38915023 PMCID: PMC11197168 DOI: 10.1186/s13104-024-06835-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 06/17/2024] [Indexed: 06/26/2024] Open
Abstract
OBJECTIVE New characterized carbohydrate-active enzymes are needed for use as tools to discriminate complex carbohydrate structural features. Fungal glycoside hydrolase family 3 (GH3) β-xylosidases have been shown to be useful for the structural elucidation of glucuronic acid (GlcA) and arabinofuranose (Araf) substituted oligoxylosides. A homolog of these GH3 fungal enzymes from the bacterium Segatella baroniae (basonym Prevotella bryantii), Xyl3C, has been previously characterized, but those studies did not address important functional specificity features. In an interest to utilize this enzyme for laboratory methods intended to discriminate the structure of the non-reducing terminus of substituted xylooligosaccharides, we have further characterized this GH3 xylosidase. RESULTS In addition to verification of basic functional characteristics of this xylosidase we have determined its mode of action as it relates to non-reducing end xylose release from GlcA and Araf substituted oligoxylosides. Xyl3C cleaves xylose from the non-reducing terminus of β-1,4-xylan until occurrence of a penultimate substituted xylose. If this substitution is O2 linked, then Xyl3C removes the non-reducing xylose to leave the substituted xylose as the new non-reducing terminus. However, if the substitution is O3 linked, Xyl3C does not hydrolyze, thus leaving the substitution one-xylose (penultimate) from the non-reducing terminus. Hence, Xyl3C enables discrimination between O2 and O3 linked substitutions on the xylose penultimate to the non-reducing end. These findings are contrasted using a homologous enzyme also from S. baroniae, Xyl3B, which is found to yield a penultimate substituted nonreducing terminus regardless of which GlcA or Araf substitution exists.
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Affiliation(s)
- Franz J St John
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Dr, Madison, WI, 53726, USA.
| | - Loreen Bynum
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Dr, Madison, WI, 53726, USA
| | - Dante A Tauscheck
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Dr, Madison, WI, 53726, USA
| | - Casey Crooks
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Dr, Madison, WI, 53726, USA
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Tryfona T, Pankratova Y, Petrik D, Rebaque Moran D, Wightman R, Yu X, Echevarría-Poza A, Deralia PK, Vilaplana F, Anderson CT, Hong M, Dupree P. Altering the substitution and cross-linking of glucuronoarabinoxylans affects cell wall architecture in Brachypodium distachyon. THE NEW PHYTOLOGIST 2024; 242:524-543. [PMID: 38413240 DOI: 10.1111/nph.19624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 02/05/2024] [Indexed: 02/29/2024]
Abstract
The Poaceae family of plants provides cereal crops that are critical for human and animal nutrition, and also, they are an important source of biomass. Interacting plant cell wall components give rise to recalcitrance to digestion; thus, understanding the wall molecular architecture is important to improve biomass properties. Xylan is the main hemicellulose in grass cell walls. Recently, we reported structural variation in grass xylans, suggesting functional specialisation and distinct interactions with cellulose and lignin. Here, we investigated the functions of these xylans by perturbing the biosynthesis of specific xylan types. We generated CRISPR/Cas9 knockout mutants in Brachypodium distachyon XAX1 and GUX2 genes involved in xylan substitution. Using carbohydrate gel electrophoresis, we identified biochemical changes in different xylan types. Saccharification, cryo-SEM, subcritical water extraction and ssNMR were used to study wall architecture. BdXAX1A and BdGUX2 enzymes modify different types of grass xylan. Brachypodium mutant walls are likely more porous, suggesting the xylan substitutions directed by both BdXAX1A and GUX2 enzymes influence xylan-xylan and/or xylan-lignin interactions. Since xylan substitutions influence wall architecture and digestibility, our findings open new avenues to improve cereals for food and to use grass biomass for feed and the production of bioenergy and biomaterials.
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Affiliation(s)
- Theodora Tryfona
- Department of Biochemistry, School of Biological Sciences, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Yanina Pankratova
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, NW14-3212, USA
| | - Deborah Petrik
- Department of Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Diego Rebaque Moran
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, Stockholm, SE-106, Sweden
- Centro de Biotecnologia y Genomica de Plants (UPM-INIA/CSIC), Universidad Politecnica de Madrid, Pozuelo de Alarcon (Madrid), 28223, Spain
| | | | - Xiaolan Yu
- Department of Biochemistry, School of Biological Sciences, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Alberto Echevarría-Poza
- Department of Biochemistry, School of Biological Sciences, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Parveen Kumar Deralia
- Department of Biochemistry, School of Biological Sciences, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Francisco Vilaplana
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, Stockholm, SE-106, Sweden
- Wallenberg Wood Science Centre, KTH Royal Institute of Technology, Stockholm, SE-11, Sweden
| | - Charles T Anderson
- Department of Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, NW14-3212, USA
| | - Paul Dupree
- Department of Biochemistry, School of Biological Sciences, University of Cambridge, Cambridge, CB2 1QW, UK
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Bains RK, Nasseri SA, Liu F, Wardman JF, Rahfeld P, Withers SG. Characterization of a new family of 6-sulfo-N-acetylglucosaminidases. J Biol Chem 2023; 299:105214. [PMID: 37660924 PMCID: PMC10570127 DOI: 10.1016/j.jbc.2023.105214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/12/2023] [Accepted: 08/18/2023] [Indexed: 09/05/2023] Open
Abstract
Sulfation is widespread in nature and plays an important role in modulating biological function. Among the strategies developed by microbes to access sulfated oligosaccharides as a nutrient source is the production of 6-sulfoGlcNAcases to selectively release 6-sulfoGlcNAc from target oligosaccharides. Thus far, all 6-sulfoGlcNAcases identified have belonged to the large GH20 family of β-hexosaminidases. Ηere, we identify and characterize a new, highly specific non-GH20 6-sulfoGlcNAcase from Streptococcus pneumoniae TIGR4, Sp_0475 with a greater than 110,000-fold preference toward N-acetyl-β-D-glucosamine-6-sulfate substrates over the nonsulfated version. Sp_0475 shares distant sequence homology with enzymes of GH20 and with the newly formed GH163 family. However, the sequence similarity between them is sufficiently low that Sp_0475 has been assigned as the founding member of a new glycoside hydrolase family, GH185. By combining results from site-directed mutagenesis with mechanistic studies and bioinformatics we provide insight into the substrate specificity, mechanism, and key active site residues of Sp_0475. Enzymes of the GH185 family follow a substrate-assisted mechanism, consistent with their distant homology to the GH20 family, but the catalytic residues involved are quite different. Taken together, our results highlight in more detail how microbes can degrade sulfated oligosaccharides for nutrients.
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Affiliation(s)
- Rajneesh K Bains
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Seyed A Nasseri
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Feng Liu
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jacob F Wardman
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter Rahfeld
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stephen G Withers
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada.
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Khamassi A, Dumon C. Enzyme synergy for plant cell wall polysaccharide degradation. Essays Biochem 2023; 67:521-531. [PMID: 37067158 DOI: 10.1042/ebc20220166] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/17/2023] [Accepted: 03/07/2023] [Indexed: 04/18/2023]
Abstract
Valorizing plant cell wall, marine and algal polysaccharides is of utmost importance for the development of the circular bioeconomy. This is because polysaccharides are by far the most abundant organic molecules found in nature with complex chemical structures that require a large set of enzymes for their degradation. Microorganisms produce polysaccharide-specific enzymes that act in synergy when performing hydrolysis. Although discovered since decades enzyme synergy is still poorly understood at the molecular level and thus it is difficult to harness and optimize. In the last few years, more attention has been given to improve and characterize enzyme synergy for polysaccharide valorization. In this review, we summarize literature to provide an overview of the different type of synergy involving carbohydrate modifying enzymes and the recent advances in the field exemplified by plant cell-wall degradation.
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Affiliation(s)
- Ahmed Khamassi
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Claire Dumon
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
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Li S, Li T, Wang B, Wen C, Li M, Ding K. A structure defined pectin SA02B from Semiaquilegia adoxoides is metabolized by human gut microbes. Int J Biol Macromol 2023; 234:123673. [PMID: 36801222 DOI: 10.1016/j.ijbiomac.2023.123673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 02/03/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023]
Abstract
Polysaccharide is one of the major factors for shaping the gut microbiota. However, bioactivity of polysaccharide isolated from Semiaquilegia adoxoides on human gut microbiota remains unclear. Thus, we hypothesize gut microbes may act on it. Herein, pectin SA02B from the roots of Semiaquilegia adoxoides with molecular weight 69.26 kDa was elucidated. The backbone of SA02B was composed of alternate 1, 2-linked α-Rhap and 1, 4-linked α-GalpA, with branches of terminal (T) -, 1, 4-, 1, 3- and 1, 3, 6-linked β-Galp, T-, 1, 5- and 1, 3, 5-linked α-Araf and T-, 1, 4-linked-β-Xylp substituted at C-4 of 1, 2, 4-linked α-Rhap. Bioactivity screening showed SA02B promoted the growth of Bacteroides spp. which deconstructed it into monosaccharide. Simultaneously, we observed competition might exist between Bacteroides spp. and probiotics. Besides, we found that both Bacteroides spp. and probiotics could generate SCFAs grown on SA02B. Our findings highlight SA02B may deserve as a prebiotic to be explored to benefit the health gut microbiota.
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Affiliation(s)
- Saijuan Li
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Nanjing 210023, China; Glycochemistry and Glycobiology Lab, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China; Kweichow Maotai Hospital, Zunyi Medical University, Zhongshu Central Street, Renhuai 564500, China
| | - Tingting Li
- School of Pharmacy, Zunyi Medical University, 201 Dalian Road, Zunyi 563003, China; Glycochemistry and Glycobiology Lab, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Binqiang Wang
- School of Pharmacy, Zunyi Medical University, 201 Dalian Road, Zunyi 563003, China; Glycochemistry and Glycobiology Lab, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Chang Wen
- School of Pharmacy, Zunyi Medical University, 201 Dalian Road, Zunyi 563003, China; Glycochemistry and Glycobiology Lab, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Meixia Li
- Glycochemistry and Glycobiology Lab, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China.
| | - Kan Ding
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Nanjing 210023, China; School of Pharmacy, Zunyi Medical University, 201 Dalian Road, Zunyi 563003, China; Glycochemistry and Glycobiology Lab, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China.
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Tryfona T, Bourdon M, Delgado Marques R, Busse‐Wicher M, Vilaplana F, Stott K, Dupree P. Grass xylan structural variation suggests functional specialization and distinctive interaction with cellulose and lignin. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 113:1004-1020. [PMID: 36602010 PMCID: PMC10952629 DOI: 10.1111/tpj.16096] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
Xylan is the most abundant non-cellulosic polysaccharide in grass cell walls, and it has important structural roles. The name glucuronoarabinoxylan (GAX) is used to describe this variable hemicellulose. It has a linear backbone of β-1,4-xylose (Xyl) residues that may be substituted with α-1,2-linked (4-O-methyl)-glucuronic acid (GlcA), α-1,3-linked arabinofuranose (Araf), and sometimes acetylation at the O-2 and/or O-3 positions. The role of these substitutions remains unclear, although there is increasing evidence that they affect the way xylan interacts with other cell wall components, particularly cellulose and lignin. Here, we used substitution-dependent endo-xylanase enzymes to investigate the variability of xylan substitution in grass culm cell walls. We show that there are at least three different types of xylan: (i) an arabinoxylan with evenly distributed Araf substitutions without GlcA (AXe); (ii) a glucuronoarabinoxylan with clustered GlcA modifications (GAXc); and (iii) a highly substituted glucuronoarabinoxylan (hsGAX). Immunolocalization of AXe and GAXc in Brachypodium distachyon culms revealed that these xylan types are not restricted to a few cell types but are instead widely detected in Brachypodium cell walls. We hypothesize that there are functionally specialized xylan types within the grass cell wall. The even substitutions of AXe may permit folding and binding on the surface of cellulose fibrils, whereas the more complex substitutions of the other xylans may support a role in the matrix and interaction with other cell wall components.
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Affiliation(s)
- Theodora Tryfona
- Department of Biochemistry, School of Biological SciencesUniversity of CambridgeCambridgeCB2 1QWUK
| | | | - Rita Delgado Marques
- Department of Biochemistry, School of Biological SciencesUniversity of CambridgeCambridgeCB2 1QWUK
| | - Marta Busse‐Wicher
- Department of Biochemistry, School of Biological SciencesUniversity of CambridgeCambridgeCB2 1QWUK
| | - Francisco Vilaplana
- Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and HealthKTH Royal Institute of TechnologyStockholmSE‐10691Sweden
| | - Katherine Stott
- Department of Biochemistry, School of Biological SciencesUniversity of CambridgeCambridgeCB2 1QWUK
| | - Paul Dupree
- Department of Biochemistry, School of Biological SciencesUniversity of CambridgeCambridgeCB2 1QWUK
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The Glycoside Hydrolase Family 35 β-galactosidase from Trichoderma reesei debranches xyloglucan oligosaccharides from tamarind and jatobá. Biochimie 2023; 211:16-24. [PMID: 36828153 DOI: 10.1016/j.biochi.2023.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023]
Abstract
Trichoderma reesei (anamorph Hypocrea jecorina) produces an extracellular beta-galactosidase from Glycoside Hydrolase Family 35 (TrBga1). Hydrolysis of xyloglucan oligosaccharides (XGOs) by TrBga1 has been studied by hydrolysis profile analysis of both tamarind (Tamarindus indica) and jatobá (Hymenaea courbaril) seed storage xyloglucans using PACE and MALDI-ToF-MS for separation, quantification and identification of the hydrolysis products. The TrBga1 substrate preference for galactosylated oligosaccharides from both the XXXG- and XXXXG-series of jatobá xyloglucan showed that the doubly galactosylated oligosaccharides were the first to be hydrolyzed. Furthermore, the TrBga1 showed more efficient hydrolysis against non-reducing end dexylosylated oligosaccharides (GLXG/GXLG and GLLG). This preference may play a key role in xyloglucan degradation, since galactosyl removal alleviates steric hindrance for other enzymes in the xyloglucanolytic complex resulting in complete xyloglucan mobilization. Indeed, mixtures of TrBga1 with the α-xylosidase from Escherichia coli (YicI), which shows a preference towards non-galactosylated xyloglucan oligosaccharides, reveals efficient depolymerization when either enzyme is applied first. This understanding of the synergistic depolymerization contributes to the knowledge of plant cell wall structure, and reveals possible evolutionary mechanisms directing the preferences of debranching enzymes acting on xyloglucan oligosaccharides.
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Tõlgo M, Hegnar OA, Larsbrink J, Vilaplana F, Eijsink VGH, Olsson L. Enzymatic debranching is a key determinant of the xylan-degrading activity of family AA9 lytic polysaccharide monooxygenases. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:2. [PMID: 36604763 PMCID: PMC9814446 DOI: 10.1186/s13068-022-02255-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND Previous studies have revealed that some Auxiliary Activity family 9 (AA9) lytic polysaccharide monooxygenases (LPMOs) oxidize and degrade certain types of xylans when incubated with mixtures of xylan and cellulose. Here, we demonstrate that the xylanolytic activities of two xylan-active LPMOs, TtLPMO9E and TtLPMO9G from Thermothielavioides terrestris, strongly depend on the presence of xylan substitutions. RESULTS Using mixtures of phosphoric acid-swollen cellulose (PASC) and wheat arabinoxylan (WAX), we show that removal of arabinosyl substitutions with a GH62 arabinofuranosidase resulted in better adsorption of xylan to cellulose, and enabled LPMO-catalyzed cleavage of this xylan. Furthermore, experiments with mixtures of PASC and arabinoglucuronoxylan from spruce showed that debranching of xylan with the GH62 arabinofuranosidase and a GH115 glucuronidase promoted LPMO activity. Analyses of mixtures with PASC and (non-arabinosylated) beechwood glucuronoxylan showed that GH115 action promoted LPMO activity also on this xylan. Remarkably, when WAX was incubated with Avicel instead of PASC in the presence of the GH62, both xylan and cellulose degradation by the LPMO9 were impaired, showing that the formation of cellulose-xylan complexes and their susceptibility to LPMO action also depend on the properties of the cellulose. These debranching effects not only relate to modulation of the cellulose-xylan interaction, which influences the conformation and rigidity of the xylan, but likely also affect the LPMO-xylan interaction, because debranching changes the architecture of the xylan surface. CONCLUSIONS Our results shed new light on xylanolytic LPMO9 activity and on the functional interplay and possible synergies between the members of complex lignocellulolytic enzyme cocktails. These findings will be relevant for the development of future lignocellulolytic cocktails and biomaterials.
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Affiliation(s)
- Monika Tõlgo
- grid.5371.00000 0001 0775 6028Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden ,grid.5371.00000 0001 0775 6028Wallenberg Wood Science Centre, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Olav A. Hegnar
- grid.19477.3c0000 0004 0607 975XFaculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Johan Larsbrink
- grid.5371.00000 0001 0775 6028Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden ,grid.5371.00000 0001 0775 6028Wallenberg Wood Science Centre, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Francisco Vilaplana
- grid.5037.10000000121581746Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden ,grid.5037.10000000121581746Wallenberg Wood Science Centre, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - Vincent G. H. Eijsink
- grid.19477.3c0000 0004 0607 975XFaculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Lisbeth Olsson
- grid.5371.00000 0001 0775 6028Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden ,grid.5371.00000 0001 0775 6028Wallenberg Wood Science Centre, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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Granborg JR, Kaasgaard SG, Janfelt C. Variation in oligosaccharide profiles observed with AP-MALDI in different regions of maize kernels after treatment with xylanases. J Cereal Sci 2022. [DOI: 10.1016/j.jcs.2022.103586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Akram F, Haq IU, Shah FI, Aqeel A, Ahmed Z, Mir AS, Qureshi SS, Raja SI. Genus Thermotoga: A valuable home of multifunctional glycoside hydrolases (GHs) for industrial sustainability. Bioorg Chem 2022; 127:105942. [PMID: 35709577 DOI: 10.1016/j.bioorg.2022.105942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 06/04/2022] [Accepted: 06/07/2022] [Indexed: 11/17/2022]
Abstract
Nature is a dexterous and prolific chemist for cataloging a number of hostile niches that are the ideal residence of various thermophiles. Apart from having other species, these subsurface environments are considered a throne of bacterial genus Thermotoga. The genome sequence of Thermotogales encodes complex and incongruent clusters of glycoside hydrolases (GHs), which are superior to their mesophilic counterparts and play a prominent role in various applications due to their extreme intrinsic stability. They have a tremendous capacity to use a wide variety of simple and multifaceted carbohydrates through GHs, formulate fermentative hydrogen and bioethanol at extraordinary yield, and catalyze high-temperature reactions for various biotechnological applications. Nevertheless, no stringent rules exist for the thermo-stabilization of biocatalysts present in the genus Thermotoga. These enzymes endure immense attraction in fundamental aspects of how these polypeptides attain and stabilize their distinctive three-dimensional (3D) structures to accomplish their physiological roles. Moreover, numerous genome sequences from Thermotoga species have revealed a significant fraction of genes most closely related to those of archaeal species, thus firming a staunch belief of lateral gene transfer mechanism. However, the question of its magnitude is still in its infancy. In addition to GHs, this genus is a paragon of encapsulins which carry pharmacological and industrial significance in the field of life sciences. This review highlights an intricate balance between the genomic organizations, factors inducing the thermostability, and pharmacological and industrial applications of GHs isolated from genus Thermotoga.
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Affiliation(s)
- Fatima Akram
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan.
| | - Ikram Ul Haq
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan; Pakistan Academy of Science, Islamabad, Pakistan
| | - Fatima Iftikhar Shah
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan
| | - Amna Aqeel
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan
| | - Zeeshan Ahmed
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan
| | - Azka Shahzad Mir
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan
| | - Sumbal Sajid Qureshi
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan
| | - Saleha Ibadat Raja
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan
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12
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Wilkens C, Vuillemin M, Pilgaard B, Polikarpov I, Morth JP. A GH115 α-glucuronidase structure reveals dimerization-mediated substrate binding and a proton wire potentially important for catalysis. Acta Crystallogr D Struct Biol 2022; 78:658-668. [PMID: 35503213 PMCID: PMC9063842 DOI: 10.1107/s2059798322003527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 03/28/2022] [Indexed: 11/25/2022] Open
Abstract
The crystal structure of a GH115 α-glucuronidase obtained in complex with xylohexaose and Ca2+ reveals that the two molecules constituting the homodimer cooperatively bind the substrate and that a divalent ion is involved in formation of the Michaelis–Menten complex and is likely to contribute to the formation of a protein wire that is essential for catalysis. Xylan is a major constituent of plant cell walls and is a potential source of biomaterials, and the derived oligosaccharides have been shown to have prebiotic effects. Xylans can be highly substituted with different sugar moieties, which pose steric hindrance to the xylanases that catalyse the hydrolysis of the xylan backbone. One such substituent is α-d-glucuronic acid, which is linked to the O2′ position of the β-1,4 d-xylopyranoses composing the main chain of xylans. The xylan-specific α-glucuronidases from glycoside hydrolase family 115 (GH115) specifically catalyse the removal of α-d-glucuronic acid (GlcA) or methylated GlcA (MeGlcA). Here, the molecular basis by which the bacterial GH115 member wtsAgu115A interacts with the main chain of xylan and the indirect involvement of divalent ions in the formation of the Michaelis–Menten complex are described. A crystal structure at 2.65 Å resolution of wtsAgu115A originating from a metagenome from an anaerobic digester fed with wastewater treatment sludge was determined in complex with xylohexaose, and Asp303 was identified as the likely general acid. The residue acting as the general base could not be identified. However, a proton wire connecting the active site to the metal site was observed and hence a previous hypothesis suggesting a Grotthuss-like mechanism cannot be rejected. Only a single molecule was found in the asymmetric unit. However, wtsAgu115A forms a dimer with a symmetry-related molecule in the crystal lattice. The xylohexaose moieties of the xylohexaose are recognized by residues from both protomers, thus creating a xylohexaose recognition site at the dimer interface. The dimer was confirmed by analytical size-exclusion chromatography in solution. Kinetic analysis with aldouronic acids resulted in a Hill coefficient of greater than 2, suggesting cooperativity between the two binding sites. Three Ca2+ ions were identified in the wtsAgu115A structures. One Ca2+ ion is of particular interest as it is coordinated by the residues of the loops that also interact with the substrate. Activity studies showed that the presence of Mg2+ or Mn2+ resulted in a higher activity towards aldouronic acids, while the less restrictive coordination geometry of Ca2+ resulted in a decrease in activity.
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13
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Li M, Li S, Guo X, Guo C, Wang Y, Du Z, Zhang Z, Xie C, Ding K. Discrete genetic loci in human gut Bacteroides thetaiotaomicron confer pectin metabolism. Carbohydr Polym 2021; 272:118534. [PMID: 34420703 DOI: 10.1016/j.carbpol.2021.118534] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 02/09/2023]
Abstract
Although the polysaccharide utilization loci (PULs) activated by pectin have been defined, due to the complex of side-chain structure, the degradative mechanisms still remain vague. Thus, we hypothesize that there may have other specific PULs to target pectin. Here, we characterize loci-encoded proteins expressed by Bacteroides thetaiotaomicron (BT) that are involved in the pectin capturing, importation, de-branching and degradation into monosaccharides. Totally, four PULs contain ten enzymes and four glycan binding proteins which including a novel surface enzyme and a surface glycan binding protein are identified. Notably, PUL2 and PUL3 have not been reported so far. Further, we show that the degradation products support the growth of other Bacteroides spp. and probiotics. In addition, genes involved in this process are conservative in other Bacteroides spp. Our results further highlight the contribution of Bacteroides spp. to metabolism the pectic network.
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Affiliation(s)
- Meixia Li
- Glycochemistry and Glycobiology Lab, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, PR China
| | - Saijuan Li
- Glycochemistry and Glycobiology Lab, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, PR China
| | - Xiaozhen Guo
- Glycochemistry and Glycobiology Lab, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, PR China
| | - Ciliang Guo
- Glycochemistry and Glycobiology Lab, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, PR China
| | - Yeqin Wang
- Glycochemistry and Glycobiology Lab, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, PR China
| | - Zhenyun Du
- Glycochemistry and Glycobiology Lab, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, PR China
| | - Zhenqing Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Cen Xie
- Glycochemistry and Glycobiology Lab, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, PR China; University of Chinese Academy of Science, No.19A Yuquan Road, Beijing 100049, PR China.
| | - Kan Ding
- Glycochemistry and Glycobiology Lab, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, PR China; University of Chinese Academy of Science, No.19A Yuquan Road, Beijing 100049, PR China.
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14
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Kadowaki MAS, Briganti L, Evangelista DE, Echevarría-Poza A, Tryfona T, Pellegrini VOA, Nakayama DG, Dupree P, Polikarpov I. Unlocking the structural features for the xylobiohydrolase activity of an unusual GH11 member identified in a compost-derived consortium. Biotechnol Bioeng 2021; 118:4052-4064. [PMID: 34232504 DOI: 10.1002/bit.27880] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/28/2021] [Accepted: 07/04/2021] [Indexed: 11/08/2022]
Abstract
The heteropolysaccharide xylan is a valuable source of sustainable chemicals and materials from renewable biomass sources. A complete hydrolysis of this major hemicellulose component requires a diverse set of enzymes including endo-β-1,4-xylanases, β-xylosidases, acetylxylan esterases, α-l-arabinofuranosidases, and α-glucuronidases. Notably, the most studied xylanases from glycoside hydrolase family 11 (GH11) have exclusively been endo-β-1,4- and β-1,3-xylanases. However, a recent analysis of a metatranscriptome library from a microbial lignocellulose community revealed GH11 enzymes capable of releasing solely xylobiose from xylan. Although initial biochemical studies clearly indicated their xylobiohydrolase mode of action, the structural features that drive this new activity still remained unclear. It was also not clear whether the enzymes acted on the reducing or nonreducing end of the substrate. Here, we solved the crystal structure of MetXyn11 in the apo and xylobiose-bound forms. The structure of MetXyn11 revealed the molecular features that explain the observed pattern on xylooligosaccharides released by this nonreducing end xylobiohydrolase.
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Affiliation(s)
- Marco A S Kadowaki
- Grupo de Biotecnologia Molecular, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.,PhotoBioCatalysis-Biomass transformation Lab (BTL), École Interfacultaire de Bioingénieurs (EIB), Université Libre de Bruxelles, Brussels, Belgium
| | - Lorenzo Briganti
- Grupo de Biotecnologia Molecular, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
| | - Danilo E Evangelista
- Grupo de Biotecnologia Molecular, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.,Instituto de Criminalística de Andradina, Superintendência da Polícia Técnico Científica de São Paulo, Andradina, São Paulo, Brazil
| | | | - Theodora Tryfona
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Vanessa O A Pellegrini
- Grupo de Biotecnologia Molecular, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
| | - Darlan G Nakayama
- Grupo de Biotecnologia Molecular, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
| | - Paul Dupree
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Igor Polikarpov
- Grupo de Biotecnologia Molecular, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
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15
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PUL-Mediated Plant Cell Wall Polysaccharide Utilization in the Gut Bacteroidetes. Int J Mol Sci 2021; 22:ijms22063077. [PMID: 33802923 PMCID: PMC8002723 DOI: 10.3390/ijms22063077] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/07/2021] [Accepted: 03/11/2021] [Indexed: 01/16/2023] Open
Abstract
Plant cell wall polysaccharides (PCWP) are abundantly present in the food of humans and feed of livestock. Mammalians by themselves cannot degrade PCWP but rather depend on microbes resident in the gut intestine for deconstruction. The dominant Bacteroidetes in the gut microbial community are such bacteria with PCWP-degrading ability. The polysaccharide utilization systems (PUL) responsible for PCWP degradation and utilization are a prominent feature of Bacteroidetes. In recent years, there have been tremendous efforts in elucidating how PULs assist Bacteroidetes to assimilate carbon and acquire energy from PCWP. Here, we will review the PUL-mediated plant cell wall polysaccharides utilization in the gut Bacteroidetes focusing on cellulose, xylan, mannan, and pectin utilization and discuss how the mechanisms can be exploited to modulate the gut microbiota.
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16
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Tamayo-Ordóñez MC, Contreras-Esquivel JC, Ayil-Gutiérrez BA, De la Cruz-Arguijo EA, Tamayo-Ordóñez FA, Ríos-González LJ, Tamayo-Ordóñez YJ. Interspecific evolutionary relationships of alpha-glucuronidase in the genus Aspergillus. Fungal Biol 2021; 125:560-575. [PMID: 34140152 DOI: 10.1016/j.funbio.2021.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 02/05/2021] [Accepted: 02/21/2021] [Indexed: 12/15/2022]
Abstract
The increased availability and production of lignocellulosic agroindustrial wastes has originated proposals for their use as raw material to obtain biofuels (ethanol and biodiesel) or derived products. However, for biomass generated from lignocellulosic residues to be successfully degraded, in most cases it requires a physical (thermal), chemical, or enzymatic pretreatment before the application of microbial or enzymatic fermentation technologies (biocatalysis). In the context of enzymatic technologies, fungi have demonstrated to produce enzymes capable of degrading polysaccharides like cellulose, hemicelluloses and pectin. Because of this ability for degrading lignocellulosic material, researchers are making efforts to isolate and identify fungal enzymes that could have a better activity for the degradation of plant cell walls and agroindustrial biomass. We performed an in silico analysis of alpha-glucoronidase in 82 accessions of the genus Aspergillus. The constructed dendrograms of amino acid sequences defined the formation of 6 groups (I, II, III, IV, V, and VI), which demonstrates the high diversity of the enzyme. Despite this ample divergence between enzyme groups, our 3D structure modeling showed both conservation and differences in amino acid residues participating in enzyme-substrate binding, which indicates the possibility that some enzymes are functionally specialized for the specific degradation of a substrate depending on the genetics of each species in the genus and the condition of the habitat where they evolved. The identification of alpha-glucuronidase isoenzymes would allow future use of genetic engineering and biocatalysis technologies aimed at specific production of the enzyme for its use in biotransformation.
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Affiliation(s)
- M C Tamayo-Ordóñez
- Laboratorio de Ingeniería Genética, Departamento de Biotecnología, Facultad de Ciencias Químicas, Universidad Autónoma de Coahuila, Ing J. Cárdenas Valdez S/N, República, 25280, Saltillo, Coah, Mexico
| | - J C Contreras-Esquivel
- Laboratorio de Glicobiotecnologia Aplicada, Departamento de Ciencia y Tecnología de Alimentos, Facultad de Ciencias Químicas, Universidad Autónoma de Coahuila, Ing. J. Cárdenas Valdez S/N, República, 25280, Saltillo, Coah, Mexico
| | - B A Ayil-Gutiérrez
- CONACYT- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Biotecnologia Vegetal. Blvd. del Maestro, s/n, Esq. Elías Piña, Reynosa, 88710, Mexico
| | - E A De la Cruz-Arguijo
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Blvd. del Maestro, s/n, Esq. Elías Piña, Reynosa, 88710, Mexico
| | - F A Tamayo-Ordóñez
- Facultad de Química, Universidad Autónoma del Carmen, Calle 56 No. 4 por Av. Concordia, Campus Principal, 24180, Ciudad del Carmen, Campeche, Mexico
| | - L J Ríos-González
- Departamento de Biotecnología, Facultad de Ciencias Químicas, Universidad Autónoma de Coahuila, Ing Cárdenas Valdez S/N, República, 25280, Saltillo, Coah, Mexico
| | - Y J Tamayo-Ordóñez
- Estancia Posdoctoral Nacional-CONACyT, Posgrado en Ciencia y Tecnología de Alimentos, Facultad de Ciencias Químicas, Universidad Autónoma de Coahuila, Ing J. Cardenas Valdez S/N, República, 25280, Saltillo, Coah, Mexico.
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17
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Yan R, Wang W, Vuong TV, Xiu Y, Skarina T, Di Leo R, Gatenholm P, Toriz G, Tenkanen M, Stogios PJ, Master ER. Structural characterization of the family GH115 α-glucuronidase from Amphibacillus xylanus yields insight into its coordinated action with α-arabinofuranosidases. N Biotechnol 2021; 62:49-56. [PMID: 33486119 DOI: 10.1016/j.nbt.2021.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 01/11/2021] [Accepted: 01/16/2021] [Indexed: 01/01/2023]
Abstract
The coordinated action of carbohydrate-active enzymes has mainly been evaluated for the purpose of complete saccharification of plant biomass (lignocellulose) to sugars. By contrast, the coordinated action of accessory hemicellulases on xylan debranching and recovery is less well characterized. Here, the activity of two family GH115 α-glucuronidases (SdeAgu115A from Saccharophagus degradans, and AxyAgu115A from Amphibacillus xylanus) on spruce arabinoglucuronoxylan (AGX) was evaluated in combination with an α-arabinofuranosidase from families GH51 (AniAbf51A, aka E-AFASE from Aspergillus niger) and GH62 (SthAbf62A from Streptomyces thermoviolaceus). The α-arabinofuranosidases boosted (methyl)-glucuronic acid release by SdeAgu115A by approximately 50 % and 30 %, respectively. The impact of the α-arabinofuranosidases on AxyAgu115A activity was comparatively low, motivating its structural characterization. The crystal structure of AxyAgu115A revealed increased length and flexibility of the active site loop compared to SdeAgu115A. This structural difference could explain the ability of AxyAgu115A to accommodate more highly substituted arabinoglucuronoxylan, and inform enzyme selections for improved AGX recovery and use.
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Affiliation(s)
- Ruoyu Yan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Weijun Wang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Yang Xiu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Tatiana Skarina
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Rosa Di Leo
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Paul Gatenholm
- Department of Chemistry and Chemical Engineering, Wallenberg Wood Science Center and Biopolymer Technology, Chalmers University of Technology, Kemivägen 4, Gothenburg, 412 96, Sweden
| | - Guillermo Toriz
- Department of Wood, Cellulose and Paper Research, University of Guadalajara, Guadalajara, 44100, Mexico
| | - Maija Tenkanen
- Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 27, Helsinki, 00014, Finland
| | - Peter J Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada; Department of Bioproducts and Biosystems, Aalto University, FI-00076, Aalto, Kemistintie 1, Espoo, Finland.
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18
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Raji O, Arnling Bååth J, Vuong TV, Larsbrink J, Olsson L, Master ER. The coordinated action of glucuronoyl esterase and α-glucuronidase promotes the disassembly of lignin-carbohydrate complexes. FEBS Lett 2021; 595:351-359. [PMID: 33277689 PMCID: PMC8044923 DOI: 10.1002/1873-3468.14019] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 12/19/2022]
Abstract
Glucuronoxylans represent a significant fraction of woody biomass, and its decomposition is complicated by the presence of lignin–carbohydrate complexes (LCCs). Herein, LCCs from birchwood were used to investigate the potential coordinated action of a glucuronoyl esterase (TtCE15A) and two α‐glucuronidases (SdeAgu115A and AxyAgu115A). When supplementing α‐glucuronidase with equimolar quantities of TtCE15A, total MeGlcpA released after 72 h by SdeAgu115A and AxyAgu115A increased from 52% to 67%, and 61% to 95%, respectively. Based on the combined TtCE15A and AxyAgu115A activities, ~ 34% of MeGlcpA in the extracted birchwood glucuronoxylan was occupied as LCCs. Notably, insoluble LCC fractions reduced soluble α‐glucuronidase concentrations by up to 70%, whereas reduction in soluble TtCE15A was less than 30%, indicating different tendencies to adsorb onto the LCC substrate.
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Affiliation(s)
- Olanrewaju Raji
- Department of Chemical Engineering and Applied Science, University of Toronto, ON, Canada
| | - Jenny Arnling Bååth
- Department of Biology and Biological Engineering, Wallenberg Wood Science Center, Chalmers University of Technology, Gothenburg, Sweden
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Science, University of Toronto, ON, Canada
| | - Johan Larsbrink
- Department of Biology and Biological Engineering, Wallenberg Wood Science Center, Chalmers University of Technology, Gothenburg, Sweden
| | - Lisbeth Olsson
- Department of Biology and Biological Engineering, Wallenberg Wood Science Center, Chalmers University of Technology, Gothenburg, Sweden
| | - Emma R Master
- Department of Chemical Engineering and Applied Science, University of Toronto, ON, Canada.,Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland
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19
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Petrik DL, Tryfona T, Dupree P, Anderson CT. BdGT43B2 functions in xylan biosynthesis and is essential for seedling survival in Brachypodium distachyon. PLANT DIRECT 2020; 4:e00216. [PMID: 32342027 PMCID: PMC7181411 DOI: 10.1002/pld3.216] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 02/25/2020] [Accepted: 03/26/2020] [Indexed: 05/22/2023]
Abstract
Xylan is the predominant hemicellulose in the primary cell walls of grasses, but its synthesis and interactions with other wall polysaccharides are complex and incompletely understood. To probe xylan biosynthesis, we generated CRISPR/Cas9 knockout and amiRNA knockdown lines of BdGT43B2, an ortholog of the wheat TaGT43-4 xylan synthase scaffolding protein in the IRX14 clade, in Brachypodium distachyon. Knockout of BdGT43B2 caused stunting and premature death in Brachypodium seedlings. Immunofluorescence labeling of xylans was greatly reduced in homozygous knockout BdGT43B2 mutants, whereas cellulose labeling was unchanged or slightly increased. Biochemical analysis showed reductions in digestible xylan in knockout mutant walls, and cell size was smaller in knockout leaves. BdGT43B2 knockdown plants appeared morphologically normal as adults, but showed slight reductions in seedling growth and small decreases in xylose content in isolated cell walls. Immunofluorescence labeling of xylan and cellulose staining was both reduced in BdGT43B2 knockdown plants. Together, these data indicate that BdGT43B2 functions in the synthesis of a form of xylan that is required for seedling growth and survival in Brachypodium distachyon.
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Affiliation(s)
- Deborah L. Petrik
- Department of BiologyThe Pennsylvania State UniversityUniversity ParkPAUSA
- Molecular BiologyNortheastern State UniversityTahlequahOklahoma
| | | | - Paul Dupree
- Department of BiochemistryUniversity of CambridgeCambridgeUK
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20
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Malgas S, Mafa MS, Mkabayi L, Pletschke BI. A mini review of xylanolytic enzymes with regards to their synergistic interactions during hetero-xylan degradation. World J Microbiol Biotechnol 2019; 35:187. [PMID: 31728656 DOI: 10.1007/s11274-019-2765-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 11/06/2019] [Indexed: 10/25/2022]
Abstract
This review examines the recent models describing the mode of action of various xylanolytic enzymes and how these enzymes can be applied (sequentially or simultaneously) with their distinctive roles in mind to achieve efficient xylan degradation. With respect to homeosynergy, synergism appears to be as a result of β-xylanase and/or oligosaccharide reducing-end β-xylanase liberating xylo-oligomers (XOS) that are preferred substrates of the processive β-xylosidase. With regards to hetero-synergism, two cross relationships appear to exist and seem to be the reason for synergism between the enzymes during xylan degradation. These cross relations are the debranching enzymes such as α-glucuronidase or side-chain cleaving enzymes such as carbohydrate esterases (CE) removing decorations that would have hindered back-bone-cleaving enzymes, while backbone-cleaving-enzymes liberate XOS that are preferred substrates of the debranching and side-chain-cleaving enzymes. This interaction is demonstrated by high yields in co-production of xylan substituents such as arabinose, glucuronic acid and ferulic acid, and XOS. Finally, lytic polysaccharide monooxygenases (LPMO) have also been implicated in boosting whole lignocellulosic biomass or insoluble xylan degradation by glycoside hydrolases (GH) by possibly disrupting entangled xylan residues. Since it has been observed that the same enzyme (same Enzyme Commission, EC, classification) from different GH or CE and/or AA families can display different synergistic interactions with other enzymes due to different substrate specificities and properties, in this review, we propose an approach of enzyme selection (and mode of application thereof) during xylan degradation, as this can improve the economic viability of the degradation of xylan for producing precursors of value added products.
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Affiliation(s)
- Samkelo Malgas
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, Eastern Cape, 6140, South Africa
| | - Mpho S Mafa
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, Eastern Cape, 6140, South Africa.,Protein Structure-Function Research Unit (PSFRU), School of Molecular and Cell Biology, Wits University, Johannesburg, Gauteng, 2000, South Africa
| | - Lithalethu Mkabayi
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, Eastern Cape, 6140, South Africa
| | - Brett I Pletschke
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, Eastern Cape, 6140, South Africa.
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21
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Tryfona T, Sorieul M, Feijao C, Stott K, Rubtsov DV, Anders N, Dupree P. Development of an oligosaccharide library to characterise the structural variation in glucuronoarabinoxylan in the cell walls of vegetative tissues in grasses. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:109. [PMID: 31080516 PMCID: PMC6501314 DOI: 10.1186/s13068-019-1451-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/25/2019] [Indexed: 05/06/2023]
Abstract
BACKGROUND Grass glucuronoarabinoxylan (GAX) substitutions can inhibit enzymatic degradation and are involved in the interaction of xylan with cell wall cellulose and lignin, factors which contribute to the recalcitrance of biomass to saccharification. Therefore, identification of xylan characteristics central to biomass biorefining improvement is essential. However, the task of assessing biomass quality is complicated and is often hindered by the lack of a reference for a given crop. RESULTS In this study, we created a reference library, expressed in glucose units, of Miscanthus sinensis GAX stem and leaf oligosaccharides, using DNA sequencer-Assisted Saccharide analysis in high throughput (DASH), supported by liquid chromatography (LC), nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Our analysis of a number of grass species highlighted variations in substitution type and frequency of stem and leaf GAX. In miscanthus, for example, the β-Xylp-(1 → 2)-α-Araf-(1 → 3) side chain is more abundant in leaf than stem. CONCLUSIONS The reference library allows fast identification and comparison of GAX structures from different plants and tissues. Ultimately, this reference library can be used in directing biomass selection and improving biorefining.
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Affiliation(s)
- Theodora Tryfona
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge, CB2 1QW UK
| | - Mathias Sorieul
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge, CB2 1QW UK
- Present Address: Scion, 49 Sala Street, Private Bag 3020, Rotorua, 3046 New Zealand
| | - Carolina Feijao
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge, CB2 1QW UK
- Present Address: Frontiers, WeWork, 1 Fore St, London, EC2Y 5EJ UK
| | - Katherine Stott
- Department of Biochemistry, University of Cambridge, Sanger Building, 80 Tennis Court Road, Cambridge, CB2 1GA UK
| | - Denis V. Rubtsov
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge, CB2 1QW UK
- Present Address: ideaSpace South, Cambridge Biomedical Campus, Bay 13 Hills Road, Cambridge, CB2 0SP UK
| | - Nadine Anders
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge, CB2 1QW UK
| | - Paul Dupree
- Department of Biochemistry, University of Cambridge, Hopkins Building, The Downing Site, Tennis Court Road, Cambridge, CB2 1QW UK
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22
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Jensen JK, Busse‐Wicher M, Poulsen CP, Fangel JU, Smith PJ, Yang J, Peña M, Dinesen MH, Martens HJ, Melkonian M, Wong GK, Moremen KW, Wilkerson CG, Scheller HV, Dupree P, Ulvskov P, Urbanowicz BR, Harholt J. Identification of an algal xylan synthase indicates that there is functional orthology between algal and plant cell wall biosynthesis. THE NEW PHYTOLOGIST 2018; 218:1049-1060. [PMID: 29460505 PMCID: PMC5902652 DOI: 10.1111/nph.15050] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/14/2018] [Indexed: 05/18/2023]
Abstract
Insights into the evolution of plant cell walls have important implications for comprehending these diverse and abundant biological structures. In order to understand the evolving structure-function relationships of the plant cell wall, it is imperative to trace the origin of its different components. The present study is focused on plant 1,4-β-xylan, tracing its evolutionary origin by genome and transcriptome mining followed by phylogenetic analysis, utilizing a large selection of plants and algae. It substantiates the findings by heterologous expression and biochemical characterization of a charophyte alga xylan synthase. Of the 12 known gene classes involved in 1,4-β-xylan formation, XYS1/IRX10 in plants, IRX7, IRX8, IRX9, IRX14 and GUX occurred for the first time in charophyte algae. An XYS1/IRX10 ortholog from Klebsormidium flaccidum, designated K. flaccidumXYLAN SYNTHASE-1 (KfXYS1), possesses 1,4-β-xylan synthase activity, and 1,4-β-xylan occurs in the K. flaccidum cell wall. These data suggest that plant 1,4-β-xylan originated in charophytes and shed light on the origin of one of the key cell wall innovations to occur in charophyte algae, facilitating terrestrialization and emergence of polysaccharide-based plant cell walls.
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Affiliation(s)
- Jacob Krüger Jensen
- Department of Plant BiologyMichigan State UniversityEast LansingMI48823USA
- DOE Great Lakes Bioenergy Research CenterMichigan State UniversityEast LansingMI48823USA
| | | | | | | | - Peter James Smith
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
- BioEnergy Science CenterOak Ridge National Lab LaboratoryOak RidgeTN37831USA
| | - Jeong‐Yeh Yang
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Maria‐Jesus Peña
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
- BioEnergy Science CenterOak Ridge National Lab LaboratoryOak RidgeTN37831USA
| | | | - Helle Juel Martens
- Department of Plant and Environmental SciencesUniversity of Copenhagen1971Frederiksberg CDenmark
| | - Michael Melkonian
- Botanical InstituteDepartment of Biological SciencesUniversität zu KölnKölnD‐50674Germany
| | - Gane Ka‐Shu Wong
- BGI‐ShenzhenBeishan Industrial ZoneYantian DistrictShenzhen518083China
| | - Kelley W. Moremen
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Curtis Gene Wilkerson
- Department of Plant BiologyMichigan State UniversityEast LansingMI48823USA
- DOE Great Lakes Bioenergy Research CenterMichigan State UniversityEast LansingMI48823USA
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingMI48824USA
| | - Henrik Vibe Scheller
- Joint BioEnergy InstituteEmeryvilleCA94608USA
- Environmental Genomics and Systems Biology DivisionLawrence Berkeley National LaboratoryBerkeleyCA94720USA
| | - Paul Dupree
- Department of BiochemistryUniversity of CambridgeCambridgeCB2 1QWUK
| | - Peter Ulvskov
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Breeanna Rae Urbanowicz
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
- BioEnergy Science CenterOak Ridge National Lab LaboratoryOak RidgeTN37831USA
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23
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Jiménez DJ, Chaib De Mares M, Salles JF. Temporal Expression Dynamics of Plant Biomass-Degrading Enzymes by a Synthetic Bacterial Consortium Growing on Sugarcane Bagasse. Front Microbiol 2018. [PMID: 29535687 PMCID: PMC5834485 DOI: 10.3389/fmicb.2018.00299] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Plant biomass (PB) is an important source of sugars useful for biofuel production, whose degradation efficiency depends on synergistic and dynamic interactions of different enzymes. Here, using a metatranscriptomics-based approach, we explored the expression of PB-degrading enzymes in a five-species synthetic bacterial consortium during cultivation on sugarcane bagasse as a unique carbon source. By analyzing the temporal expression dynamics of a selection of enzymes we revealed the functional role of each consortium member and disentangled the potential interactions between them. Based on normalized expression values and the taxonomic affiliation of all the transcripts within thirty carbohydrate-active enzyme (CAZy) families, we observed a successional profile. For instance, endo-glucanases/-xylanases (e.g., GH8, GH10, and GH16) were significantly expressed at 12 h, whereas exo-glucanases (e.g., GH6 and GH48) and α-arabinosidases/β-xylosidases (e.g., GH43) were highly expressed at 48 h. Indeed, a significant peak of extracellular β-xylosidase activity was observed at this stage. Moreover, we observed a higher expression of several CAZy families at 12-48 h, suggesting easy access to the main plant polysaccharides. Based on this evidence, we predicted that the highest level of collaboration between strains takes place at the initial stages of growth. Here, Paenibacillus, Brevundimonas, and Chryseobacterium were the most important contributors, whereas Stenotrophomonas was highly active at the end of the culture (96-192 h) without contributing to a large extent to the expression of lignocellulolytic enzymes. Our results contribute to the understanding of enzymatic and ecological mechanisms within PB-degrading microbial consortia, yielding new perspectives to improve the PB saccharification processes.
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Affiliation(s)
- Diego Javier Jiménez
- Microbial Ecology Cluster, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands.,Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Maryam Chaib De Mares
- Microbial Ecology Cluster, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Joana Falcão Salles
- Microbial Ecology Cluster, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
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24
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Improving the specific activity and thermo-stability of alkaline pectate lyase from Bacillus subtilis 168 for bioscouring. Biochem Eng J 2018. [DOI: 10.1016/j.bej.2017.11.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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25
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Pidatala VR, Mahboubi A, Mortimer JC. Structural Characterization of Mannan Cell Wall Polysaccharides in Plants Using PACE. J Vis Exp 2017. [PMID: 29155734 PMCID: PMC5752419 DOI: 10.3791/56424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Plant cell wall polysaccharides are notoriously difficult to analyze, and most methods require expensive equipment, skilled operators, and large amounts of purified material. Here, we describe a simple method for gaining detailed polysaccharide structural information, including resolution of structural isomers. For polysaccharide analysis by gel electrophoresis (PACE), plant cell wall material is hydrolyzed with glycosyl hydrolases specific to the polysaccharide of interest (e.g., mannanases for mannan). Large format polyacrylamide gels are then used to separate the released oligosaccharides, which have been fluorescently labeled. Gels can be visualized with a modified gel imaging system (see Table of Materials). The resulting oligosaccharide fingerprint can either be compared qualitatively or, with replication, quantitatively. Linkage and branching information can be established using additional glycosyl hydrolases (e.g., mannosidases and galactosidases). Whilst this protocol describes a method for analyzing glucomannan structure, it can be applied to any polysaccharide for which characterized glycosyl hydrolases exist. Alternatively, it can be used to characterize novel glycosyl hydrolases using defined polysaccharide substrates.
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Affiliation(s)
- Venkataramana R Pidatala
- Joint BioEnergy Institute; Environmental and Systems Biology, BioSciences Division, Lawrence Berkeley National Laboratory
| | - Amir Mahboubi
- Joint BioEnergy Institute; Environmental and Systems Biology, BioSciences Division, Lawrence Berkeley National Laboratory
| | - Jenny C Mortimer
- Joint BioEnergy Institute; Environmental and Systems Biology, BioSciences Division, Lawrence Berkeley National Laboratory;
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26
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Yan R, Vuong TV, Wang W, Master ER. Action of a GH115 α-glucuronidase from Amphibacillus xylanus at alkaline condition promotes release of 4-O-methylglucopyranosyluronic acid from glucuronoxylan and arabinoglucuronoxylan. Enzyme Microb Technol 2017. [PMID: 28648176 DOI: 10.1016/j.enzmictec.2017.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Glucuronic acid and/or 4-O-methyl-glucuronic acid (GlcA/MeGlcA) are substituents of the main xylans present in hardwoods, conifers, and many cereal grains. α-Glucuronidases from glycoside hydrolase family GH115 can target GlcA/MeGlcA from both internally and terminally substituted regions of xylans. The current study describes the first GH115 α-glucuronidase, AxyAgu115A, from the alkaliphilic organism Amphilbacillus xylanus. AxyAgu115A was active in a wide pH range, and demonstrated better performance in alkaline condition compared to other characterized GH115 α-glucuronidases, which generally show optimal activity in acidic conditions. Specifically, its relative activity between pH 5.0 and pH 8.5 was above 80%, and was 35% of maximum at pH 10.5; although the enzyme lost 30% and 80% relative residual activity after 24-h pre-incubation at pH 9 and pH 10, respectively. AxyAgu115A was also similarly active towards glucuronoxylan as well as comparatively complex xylans such as spruce arabinoglucurunoxylan. Accommodation of complex xylans was supported by docking analyses that predicted accessibility of AxyAgu115A to branched xylo-oligosaccharides. MeGlcA release by AxyAgu115A from each xylan sample was increased by up to 30% by performing the reaction at pH 11.0 rather than pH 4.0, revealing applied benefits of AxyAgu115A for xylan recovery and processing.
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Affiliation(s)
- Ruoyu Yan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.
| | - Weijun Wang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.
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27
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Unusual active site location and catalytic apparatus in a glycoside hydrolase family. Proc Natl Acad Sci U S A 2017; 114:4936-4941. [PMID: 28396425 DOI: 10.1073/pnas.1701130114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The human gut microbiota use complex carbohydrates as major nutrients. The requirement for an efficient glycan degrading systems exerts a major selection pressure on this microbial community. Thus, we propose that these bacteria represent a substantial resource for discovering novel carbohydrate active enzymes. To test this hypothesis, we focused on enzymes that hydrolyze rhamnosidic bonds, as cleavage of these linkages is chemically challenging and there is a paucity of information on l-rhamnosidases. Here we screened the activity of enzymes derived from the human gut microbiota bacterium Bacteroides thetaiotaomicron, which are up-regulated in response to rhamnose-containing glycans. We identified an α-l-rhamnosidase, BT3686, which is the founding member of a glycoside hydrolase (GH) family, GH145. In contrast to other rhamnosidases, BT3686 cleaved l-Rha-α1,4-d-GlcA linkages through a retaining double-displacement mechanism. The crystal structure of BT3686 showed that the enzyme displayed a type A seven-bladed β-propeller fold. Mutagenesis and crystallographic studies, including the structure of BT3686 in complex with the reaction product GlcA, revealed a location for the active site among β-propeller enzymes cited on the posterior surface of the rhamnosidase. In contrast to the vast majority of GH, the catalytic apparatus of BT3686 does not comprise a pair of carboxylic acid residues but, uniquely, a single histidine functions as the only discernable catalytic amino acid. Intriguingly, the histidine, His48, is not invariant in GH145; however, when engineered into structural homologs lacking the imidazole residue, α-l-rhamnosidase activity was established. The potential contribution of His48 to the catalytic activity of BT3686 is discussed.
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28
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Lyczakowski JJ, Wicher KB, Terrett OM, Faria-Blanc N, Yu X, Brown D, Krogh KBRM, Dupree P, Busse-Wicher M. Removal of glucuronic acid from xylan is a strategy to improve the conversion of plant biomass to sugars for bioenergy. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:224. [PMID: 28932265 PMCID: PMC5606085 DOI: 10.1186/s13068-017-0902-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/07/2017] [Indexed: 05/04/2023]
Abstract
BACKGROUND Plant lignocellulosic biomass can be a source of fermentable sugars for the production of second generation biofuels and biochemicals. The recalcitrance of this plant material is one of the major obstacles in its conversion into sugars. Biomass is primarily composed of secondary cell walls, which is made of cellulose, hemicelluloses and lignin. Xylan, a hemicellulose, binds to the cellulose microfibril and is hypothesised to form an interface between lignin and cellulose. Both softwood and hardwood xylan carry glucuronic acid side branches. As xylan branching may be important for biomass recalcitrance and softwood is an abundant, non-food competing, source of biomass it is important to investigate how conifer xylan is synthesised. RESULTS Here, we show using Arabidopsis gux mutant biomass that removal of glucuronosyl substitutions of xylan can allow 30% more glucose and over 700% more xylose to be released during saccharification. Ethanol yields obtained through enzymatic saccharification and fermentation of gux biomass were double those obtained for non-mutant material. Our analysis of additional xylan branching mutants demonstrates that absence of GlcA is unique in conferring the reduced recalcitrance phenotype. As in hardwoods, conifer xylan is branched with GlcA. We use transcriptomic analysis to identify conifer enzymes that might be responsible for addition of GlcA branches onto xylan in industrially important softwood. Using a combination of in vitro and in vivo activity assays, we demonstrate that a white spruce (Picea glauca) gene, PgGUX, encodes an active glucuronosyl transferase. Glucuronic acid introduced by PgGUX reduces the sugar release of Arabidopsis gux mutant biomass to wild-type levels indicating that it can fulfil the same biological function as native glucuronosylation. CONCLUSION Removal of glucuronic acid from xylan results in the largest increase in release of fermentable sugars from Arabidopsis plants that grow to the wild-type size. Additionally, plant material used in this work did not undergo any chemical pretreatment, and thus increased monosaccharide release from gux biomass can be achieved without the use of environmentally hazardous chemical pretreatment procedures. Therefore, the identification of a gymnosperm enzyme, likely to be responsible for softwood xylan glucuronosylation, provides a mutagenesis target for genetically improved forestry trees.
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Affiliation(s)
- Jan J. Lyczakowski
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
- Natural Material Innovation Centre, University of Cambridge, 1 Scroope Terrace, Cambridge, CB2 1PX UK
- OpenPlant Synthetic Biology Research Centre, Department of Plant Sciences, University of Cambridge, Downing Site, Cambridge, CB2 3EA UK
| | - Krzysztof B. Wicher
- The Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN UK
- Ossianix, Stevenage Bioscience Catalyst, Gunnels Wood Rd, Stevenage, Hertfordshire, SG1 2FX UK
| | - Oliver M. Terrett
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
| | - Nuno Faria-Blanc
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
| | - Xiaolan Yu
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
| | - David Brown
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
- Present Address: Shell Global Solutions International BV, Lange Kleiweg 40, 2288 GK Rijswijk, The Netherlands
| | - Kristian B. R. M. Krogh
- Department of Protein Biochemistry and Stability, Novozymes A/S, Krogshøjvej 36, 2880 Bagsværd, Denmark
| | - Paul Dupree
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
- Natural Material Innovation Centre, University of Cambridge, 1 Scroope Terrace, Cambridge, CB2 1PX UK
- OpenPlant Synthetic Biology Research Centre, Department of Plant Sciences, University of Cambridge, Downing Site, Cambridge, CB2 3EA UK
| | - Marta Busse-Wicher
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
- Natural Material Innovation Centre, University of Cambridge, 1 Scroope Terrace, Cambridge, CB2 1PX UK
- OpenPlant Synthetic Biology Research Centre, Department of Plant Sciences, University of Cambridge, Downing Site, Cambridge, CB2 3EA UK
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29
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Rhee MS, Sawhney N, Kim YS, Rhee HJ, Hurlbert JC, St John FJ, Nong G, Rice JD, Preston JF. GH115 α-glucuronidase and GH11 xylanase from Paenibacillus sp. JDR-2: potential roles in processing glucuronoxylans. Appl Microbiol Biotechnol 2016; 101:1465-1476. [PMID: 27766358 DOI: 10.1007/s00253-016-7899-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 09/13/2016] [Accepted: 09/25/2016] [Indexed: 01/26/2023]
Abstract
Paenibacillus sp. JDR-2 (Pjdr2) has been studied as a model for development of bacterial biocatalysts for efficient processing of xylans, methylglucuronoxylan, and methylglucuronoarabinoxylan, the predominant hemicellulosic polysaccharides found in dicots and monocots, respectively. Pjdr2 produces a cell-associated GH10 endoxylanase (Xyn10A1) that catalyzes depolymerization of xylans to xylobiose, xylotriose, and methylglucuronoxylotriose with methylglucuronate-linked α-1,2 to the nonreducing terminal xylose. A GH10/GH67 xylan utilization regulon includes genes encoding an extracellular cell-associated Xyn10A1 endoxylanase and an intracellular GH67 α-glucuronidase active on methylglucuronoxylotriose generated by Xyn10A1 but without activity on methylglucuronoxylotetraose generated by a GH11 endoxylanase. The sequenced genome of Pjdr2 contains three paralogous genes potentially encoding GH115 α-glucuronidases found in certain bacteria and fungi. One of these, Pjdr2_5977, shows enhanced expression during growth on xylans along with Pjdr2_4664 encoding a GH11 endoxylanase. Here, we show that Pjdr2_5977 encodes a GH115 α-glucuronidase, Agu115A, with maximal activity on the aldouronate methylglucuronoxylotetraose selectively generated by a GH11 endoxylanase Xyn11 encoded by Pjdr2_4664. Growth of Pjdr2 on this methylglucuronoxylotetraose supports a process for Xyn11-mediated extracellular depolymerization of methylglucuronoxylan and Agu115A-mediated intracellular deglycosylation as an alternative to the GH10/GH67 system previously defined in this bacterium. A recombinantly expressed enzyme encoded by the Pjdr2 agu115A gene catalyzes removal of 4-O-methylglucuronate residues α-1,2 linked to internal xylose residues in oligoxylosides generated by GH11 and GH30 xylanases and releases methylglucuronate from polymeric methylglucuronoxylan. The GH115 α-glucuronidase from Pjdr2 extends the discovery of this activity to members of the phylum Firmicutes and contributes to a novel system for bioprocessing hemicelluloses.
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Affiliation(s)
- Mun Su Rhee
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.,Xycrobe Therapeutics Inc., 3210 Merryfield Row, San Diego,, CA, 92121,, USA
| | - Neha Sawhney
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN, 37235,, USA
| | - Young Sik Kim
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA
| | - Hyun Jee Rhee
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.,Department of Materials Science and Engineering, Massachusetts Institute of Technology, 6-113, Cambridge, MA, 02139,, USA
| | - Jason C Hurlbert
- Department of Chemistry, Physics and Geology, Winthrop University, Rock Hill, SC, 29733, USA
| | - Franz J St John
- Forest Products Laboratory, United States Forest Service, The United States Department of Agriculture, Madison, Madison,, WI, 53726, USA
| | - Guang Nong
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA
| | - John D Rice
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA
| | - James F Preston
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.
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30
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Towards enzymatic breakdown of complex plant xylan structures: State of the art. Biotechnol Adv 2016; 34:1260-1274. [PMID: 27620948 DOI: 10.1016/j.biotechadv.2016.09.001] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/02/2016] [Accepted: 09/07/2016] [Indexed: 02/07/2023]
Abstract
Significant progress over the past few years has been achieved in the enzymology of microbial degradation and saccharification of plant xylan, after cellulose being the most abundant natural renewable polysaccharide. Several new types of xylan depolymerizing and debranching enzymes have been described in microorganisms. Despite the increasing variety of known glycoside hydrolases and carbohydrate esterases, some xylan structures still appear quite recalcitrant. This review focuses on the mode of action of different types of depolymerizing endoxylanases and their cooperation with β-xylosidase and accessory enzymes in breakdown of complex highly branched xylan structures. Emphasis is placed on the enzymatic hydrolysis of alkali-extracted deesterified polysaccharide as well as acetylated xylan isolated from plant cell walls under non-alkaline conditions. It is also shown how the combination of selected endoxylanases and debranching enzymes can determine the nature of prebiotic xylooligosaccharides or lead to complete hydrolysis of the polysaccharide. The article also highlights the possibility for discovery of novel xylanolytic enzymes, construction of multifunctional chimeric enzymes and xylanosomes in parallel with increasing knowledge on the fine structure of the polysaccharide.
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31
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Florencio C, Cunha FM, Badino AC, Farinas CS, Ximenes E, Ladisch MR. Secretome analysis of Trichoderma reesei and Aspergillus niger cultivated by submerged and sequential fermentation processes: Enzyme production for sugarcane bagasse hydrolysis. Enzyme Microb Technol 2016; 90:53-60. [PMID: 27241292 DOI: 10.1016/j.enzmictec.2016.04.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/25/2016] [Accepted: 04/26/2016] [Indexed: 10/21/2022]
Abstract
Cellulases and hemicellulases from Trichoderma reesei and Aspergillus niger have been shown to be powerful enzymes for biomass conversion to sugars, but the production costs are still relatively high for commercial application. The choice of an effective microbial cultivation process employed for enzyme production is important, since it may affect titers and the profile of protein secretion. We used proteomic analysis to characterize the secretome of T. reesei and A. niger cultivated in submerged and sequential fermentation processes. The information gained was key to understand differences in hydrolysis of steam exploded sugarcane bagasse for enzyme cocktails obtained from two different cultivation processes. The sequential process for cultivating A. niger gave xylanase and β-glucosidase activities 3- and 8-fold higher, respectively, than corresponding activities from the submerged process. A greater protein diversity of critical cellulolytic and hemicellulolytic enzymes were also observed through secretome analyses. These results helped to explain the 3-fold higher yield for hydrolysis of non-washed pretreated bagasse when combined T. reesei and A. niger enzyme extracts from sequential fermentation were used in place of enzymes obtained from submerged fermentation. An enzyme loading of 0.7 FPU cellulase activity/g glucan was surprisingly effective when compared to the 5-15 times more enzyme loadings commonly reported for other cellulose hydrolysis studies. Analyses showed that more than 80% consisted of proteins other than cellulases whose role is important to the hydrolysis of a lignocellulose substrate. Our work combined proteomic analyses and enzymology studies to show that sequential and submerged cultivation methods differently influence both titers and secretion profile of key enzymes required for the hydrolysis of sugarcane bagasse. The higher diversity of feruloyl esterases, xylanases and other auxiliary hemicellulolytic enzymes observed in the enzyme mixtures from the sequential fermentation could be one major reason for the more efficient enzyme hydrolysis that results when using the combined secretomes from A. niger and T. reesei.
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Affiliation(s)
- Camila Florencio
- Laboratory of Renewable Resources Engineering, Department of Agricultural and Biological Engineering, Purdue University, IN 47907, West Lafayette, IN, USA; Graduate Program of Biotechnology, Federal University of Sao Carlos, 13565-905, Sao Carlos, SP, Brazil; Embrapa Instrumentation, 1452 XV de Novembro Street, 13560-970, Sao Carlos, SP, Brazil
| | - Fernanda M Cunha
- Embrapa Instrumentation, 1452 XV de Novembro Street, 13560-970, Sao Carlos, SP, Brazil; Graduate Program of Chemical Engineering, Federal University of Sao Carlos, 13565-905, Sao Carlos, SP, Brazil
| | - Alberto C Badino
- Graduate Program of Biotechnology, Federal University of Sao Carlos, 13565-905, Sao Carlos, SP, Brazil; Graduate Program of Chemical Engineering, Federal University of Sao Carlos, 13565-905, Sao Carlos, SP, Brazil
| | - Cristiane S Farinas
- Graduate Program of Biotechnology, Federal University of Sao Carlos, 13565-905, Sao Carlos, SP, Brazil; Embrapa Instrumentation, 1452 XV de Novembro Street, 13560-970, Sao Carlos, SP, Brazil; Graduate Program of Chemical Engineering, Federal University of Sao Carlos, 13565-905, Sao Carlos, SP, Brazil
| | - Eduardo Ximenes
- Laboratory of Renewable Resources Engineering, Department of Agricultural and Biological Engineering, Purdue University, IN 47907, West Lafayette, IN, USA
| | - Michael R Ladisch
- Laboratory of Renewable Resources Engineering, Department of Agricultural and Biological Engineering, Purdue University, IN 47907, West Lafayette, IN, USA.
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32
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Wang W, Yan R, Nocek BP, Vuong TV, Di Leo R, Xu X, Cui H, Gatenholm P, Toriz G, Tenkanen M, Savchenko A, Master ER. Biochemical and Structural Characterization of a Five-domain GH115 α-Glucuronidase from the Marine Bacterium Saccharophagus degradans 2-40T. J Biol Chem 2016; 291:14120-14133. [PMID: 27129264 DOI: 10.1074/jbc.m115.702944] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Indexed: 01/01/2023] Open
Abstract
Glucuronic acid (GlcAp) and/or methylglucuronic acid (MeGlcAp) decorate the major forms of xylan in hardwood and coniferous softwoods as well as many cereal grains. Accordingly, the complete utilization of glucuronoxylans or conversion to sugar precursors requires the action of main chain xylanases as well as α-glucuronidases that release the α- (1→2)-linked (Me)GlcAp side groups. Herein, a family GH115 enzymefrom the marine bacterium Saccharophagus degradans 2-40(T), SdeAgu115A, demonstrated activity toward glucuronoxylan and oligomers thereof with preference toward MeGlcAp linked to internal xylopyranosyl residues. Unique biochemical characteristics of NaCl activation were also observed. The crystal structure of SdeAgu115A revealed a five-domain architecture, with an additional insertion C(+) domain that had significant impact on the domain arrangement of SdeAgu115A monomer and its dimerization. The participation of domain C(+) in substrate binding was supported by reduced substrate inhibition upon introducing W773A, W689A, and F696A substitutions within this domain. In addition to Asp-335, the catalytic essentiality of Glu-216 was revealed by site-specific mutagenesis. A primary sequence analysis suggested that the SdeAgu115A architecture is shared by more than half of GH115 members, thus defining a distinct archetype for GH115 enzymes.
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Affiliation(s)
- Weijun Wang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Ruoyu Yan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Boguslaw P Nocek
- Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Rosa Di Leo
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Xiaohui Xu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Hong Cui
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Paul Gatenholm
- Department of Chemistry and Chemical Engineering, Wallenberg Wood Science Center and Biopolymer Technology, Chalmers University of Technology, Kemivägen 4, Gothenburg 412 96, Sweden
| | - Guillermo Toriz
- Department of Chemistry and Chemical Engineering, Wallenberg Wood Science Center and Biopolymer Technology, Chalmers University of Technology, Kemivägen 4, Gothenburg 412 96, Sweden,; Department of Wood, Cellulose and Paper Research, University of Guadalajara, Guadalajara 44100, Mexico
| | - Maija Tenkanen
- Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 27, Helsinki 00014, Finland
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada,.
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada,.
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Bajwa PK, Harrington S, Dashtban M, Lee H. Expression and Characterization of Glycosyl Hydrolase Family 115 α-Glucuronidase fromScheffersomyces stipitis. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1089/ind.2015.0031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Affiliation(s)
- Paramjit K. Bajwa
- School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - Sean Harrington
- School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - Mehdi Dashtban
- School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - Hung Lee
- School of Environmental Sciences, University of Guelph, Guelph, Canada
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Marriott PE, Gómez LD, McQueen-Mason SJ. Unlocking the potential of lignocellulosic biomass through plant science. THE NEW PHYTOLOGIST 2016; 209:1366-81. [PMID: 26443261 DOI: 10.1111/nph.13684] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 08/24/2015] [Indexed: 05/17/2023]
Abstract
The aim of producing sustainable liquid biofuels and chemicals from lignocellulosic biomass remains high on the sustainability agenda, but is challenged by the costs of producing fermentable sugars from these materials. Sugars from plant biomass can be fermented to alcohols or even alkanes, creating a liquid fuel in which carbon released on combustion is balanced by its photosynthetic capture. Large amounts of sugar are present in the woody, nonfood parts of crops and could be used for fuel production without compromising global food security. However, the sugar in woody biomass is locked up in the complex and recalcitrant lignocellulosic plant cell wall, making it difficult and expensive to extract. In this paper, we review what is known about the major polymeric components of woody plant biomass, with an emphasis on the molecular interactions that contribute to its recalcitrance to enzymatic digestion. In addition, we review the extensive research that has been carried out in order to understand and reduce lignocellulose recalcitrance and enable more cost-effective production of fuel from woody plant biomass.
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Affiliation(s)
- Poppy E Marriott
- CNAP, Department of Biology, University of York, Heslington, York, YO10 5DD, UK
| | - Leonardo D Gómez
- CNAP, Department of Biology, University of York, Heslington, York, YO10 5DD, UK
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McKee LS, Sunner H, Anasontzis GE, Toriz G, Gatenholm P, Bulone V, Vilaplana F, Olsson L. A GH115 α-glucuronidase from Schizophyllum commune contributes to the synergistic enzymatic deconstruction of softwood glucuronoarabinoxylan. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:2. [PMID: 26734072 PMCID: PMC4700659 DOI: 10.1186/s13068-015-0417-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/15/2015] [Indexed: 05/11/2023]
Abstract
BACKGROUND Lignocellulosic biomass from softwood represents a valuable resource for the production of biofuels and bio-based materials as alternatives to traditional pulp and paper products. Hemicelluloses constitute an extremely heterogeneous fraction of the plant cell wall, as their molecular structures involve multiple monosaccharide components, glycosidic linkages, and decoration patterns. The complete enzymatic hydrolysis of wood hemicelluloses into monosaccharides is therefore a complex biochemical process that requires the activities of multiple degradative enzymes with complementary activities tailored to the structural features of a particular substrate. Glucuronoarabinoxylan (GAX) is a major hemicellulose component in softwood, and its structural complexity requires more enzyme specificities to achieve complete hydrolysis compared to glucuronoxylans from hardwood and arabinoxylans from grasses. RESULTS We report the characterisation of a recombinant α-glucuronidase (Agu115) from Schizophyllum commune capable of removing (4-O-methyl)-glucuronic acid ((Me)GlcA) residues from polymeric and oligomeric xylan. The enzyme is required for the complete deconstruction of spruce glucuronoarabinoxylan (GAX) and acts synergistically with other xylan-degrading enzymes, specifically a xylanase (Xyn10C), an α-l-arabinofuranosidase (AbfA), and a β-xylosidase (XynB). Each enzyme in this mixture showed varying degrees of potentiation by the other activities, likely due to increased physical access to their respective target monosaccharides. The exo-acting Agu115 and AbfA were unable to remove all of their respective target side chain decorations from GAX, but their specific activity was significantly boosted by the addition of the endo-Xyn10C xylanase. We demonstrate that the proposed enzymatic cocktail (Agu115 with AbfA, Xyn10C and XynB) achieved almost complete conversion of GAX to arabinofuranose (Araf), xylopyranose (Xylp), and MeGlcA monosaccharides. Addition of Agu115 to the enzymatic cocktail contributes specifically to 25 % of the conversion. However, traces of residual oligosaccharides resistant to this combination of enzymes were still present after deconstruction, due to steric hindrances to enzyme access to the substrate. CONCLUSIONS Our GH115 α-glucuronidase is capable of finely tailoring the molecular structure of softwood GAX, and contributes to the almost complete saccharification of GAX in synergy with other exo- and endo-xylan-acting enzymes. This has great relevance for the cost-efficient production of biofuels from softwood lignocellulose.
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Affiliation(s)
- Lauren S. McKee
- />Wallenberg Wood Science Centre, Division of Glycoscience, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Centre, 106 91 Stockholm, Sweden
| | - Hampus Sunner
- />Wallenberg Wood Science Centre, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - George E. Anasontzis
- />Wallenberg Wood Science Centre, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Guillermo Toriz
- />Wallenberg Wood Science Centre, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
- />Department of Wood, Cellulose and Paper Research, University of Guadalajara, Guadalajara, Mexico
| | - Paul Gatenholm
- />Wallenberg Wood Science Centre, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Vincent Bulone
- />Wallenberg Wood Science Centre, Division of Glycoscience, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Centre, 106 91 Stockholm, Sweden
- />ARC Centre of Excellence in Plant Cell Walls and School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, Urrbrae, SA 5064 Australia
| | - Francisco Vilaplana
- />Wallenberg Wood Science Centre, Division of Glycoscience, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Centre, 106 91 Stockholm, Sweden
| | - Lisbeth Olsson
- />Wallenberg Wood Science Centre, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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Martínez PM, Appeldoorn MM, Gruppen H, Kabel MA. The two Rasamsonia emersonii α-glucuronidases, ReGH67 and ReGH115, show a different mode-of-action towards glucuronoxylan and glucuronoxylo-oligosaccharides. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:105. [PMID: 27195020 PMCID: PMC4870768 DOI: 10.1186/s13068-016-0519-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/05/2016] [Indexed: 05/11/2023]
Abstract
BACKGROUND The production of biofuels and biochemicals from grass-type plant biomass requires a complete utilisation of the plant cellulose and hemicellulosic xylan via enzymatic degradation to their constituent monosaccharides. Generally, physical and/or thermochemical pretreatments are performed to enable access for the subsequent added carbohydrate-degrading enzymes. Nevertheless, partly substituted xylan structures remain after pretreatment, in particular the ones substituted with (4-O-methyl-)glucuronic acids (UAme). Hence, α-glucuronidases play an important role in the degradation of UAmexylan structures facilitating the complete utilisation of plant biomass. The characterisation of α-glucuronidases is a necessity to find the right enzymes to improve degradation of recalcitrant UAmexylan structures. RESULTS The mode-of-action of two α-glucuronidases was demonstrated, both obtained from the fungus Rasamsonia emersonii; one belonging to the glycoside hydrolase (GH) family 67 (ReGH67) and the other to GH115 (ReGH115). Both enzymes functioned optimal at around pH 4 and 70 °C. ReGH67 was able to release UAme from UAme-substituted xylo-oligosaccharides (UAmeXOS), but only the UAme linked to the non-reducing end xylosyl residue was cleaved. In particular, in a mixture of oligosaccharides, UAmeXOS having a degree of polymerisation (DP) of two were hydrolysed to a further extent than longer UAmeXOS (DP 3-4). On the contrary, ReGH115 was able to release UAme from both polymeric UAmexylan and UAmeXOS. ReGH115 cleaved UAme from both internal and non-reducing end xylosyl residues, with the exception of UAme attached to the non-reducing end of a xylotriose oligosaccharide. CONCLUSION In this research, and for the first time, we define the mode-of-action of two α-glucuronidases from two different GH families both from the ascomycete R. emersonii. To date, only four α-glucuronidases classified in GH115 are characterised. ReGH67 showed limited substrate specificity towards only UAmeXOS, cleaving UAme only when attached to the non-reducing end xylosyl residue. ReGH115 was much less substrate specific compared to ReGH67, because UAme was released from both polymeric UAmexylan and UAmeXOS, from both internal and non-reducing end xylosyl residues. The characterisation of the mode-of-action of these two α-glucuronidases helps understand how R. emersonii attacks UAmexylan in plant biomass and the knowledge presented is valuable to improve enzyme cocktails for biorefinery applications.
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Affiliation(s)
- Patricia Murciano Martínez
- />Laboratory of Food Chemistry, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Maaike M. Appeldoorn
- />DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Harry Gruppen
- />Laboratory of Food Chemistry, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Mirjam A. Kabel
- />Laboratory of Food Chemistry, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
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Zheng F, Huang J, Liu X, Hu H, Long L, Chen K, Ding S. N- and C-terminal truncations of a GH10 xylanase significantly increase its activity and thermostability but decrease its SDS resistance. Appl Microbiol Biotechnol 2015; 100:3555-65. [DOI: 10.1007/s00253-015-7176-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 11/09/2015] [Accepted: 11/13/2015] [Indexed: 11/28/2022]
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Metabolic potential of Bacillus subtilis 168 for the direct conversion of xylans to fermentation products. Appl Microbiol Biotechnol 2015; 100:1501-1510. [PMID: 26559526 DOI: 10.1007/s00253-015-7124-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 09/30/2015] [Accepted: 10/20/2015] [Indexed: 10/22/2022]
Abstract
Methylglucuronoxylans (MeGXn) and methylglucuronoarabinoxylans (MeGAXn) respectively comprise most of the hemicellulose fractions in dicots and monocots and, next to cellulose, are the major resources for the production of fuels and chemicals from lignocellulosics. With either MeGXn or MeGAXn as a substrate, Bacillus subtilis 168 accumulates acidic methylglucuronoxylotriose as a limit product following the uptake and metabolism of neutral xylooligosaccharides. Secreted GH11 endoxylanase (Xyn11A), GH30 endoxylanase (Xyn30C), and GH43 arabinoxylan arabinofuranohydrolase (Axh43) respectively encoded by the xynA, xynC, and xynD genes collectively contribute to the depolymerization of MeGAXn. Studies here demonstrate the complementary roles of these enzymes in the digestion of MeGAXn. Coordinate expression of the xynD and xynC genes defines an operon accounting for the Axh43-catalyzed release of arabinose followed by Xyn30C and Xyn11A-catalyzed depolymerization of MeGAXn. Both sources generate acetate and lactate as the principal fermentation products, with yields of 26 % acetate and 32 % lactate from MeGXn compared to 22 % acetate and 21 % lactate from MeGAXn. These studies of the GH43/GH30/GH11 system in B. subtilis 168 provide a basis for the further development of B. subtilis and related species as biocatalysts for direct conversion of hemicellulose derived from energy crops as well as agricultural and forest residues to chemical feedstocks.
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Gregg KJ, Suits MDL, Deng L, Vocadlo DJ, Boraston AB. Structural Analysis of a Family 101 Glycoside Hydrolase in Complex with Carbohydrates Reveals Insights into Its Mechanism. J Biol Chem 2015; 290:25657-69. [PMID: 26304114 DOI: 10.1074/jbc.m115.680470] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Indexed: 11/06/2022] Open
Abstract
O-Linked glycosylation is one of the most abundant post-translational modifications of proteins. Within the secretory pathway of higher eukaryotes, the core of these glycans is frequently an N-acetylgalactosamine residue that is α-linked to serine or threonine residues. Glycoside hydrolases in family 101 are presently the only known enzymes to be able to hydrolyze this glycosidic linkage. Here we determine the high-resolution structures of the catalytic domain comprising a fragment of GH101 from Streptococcus pneumoniae TIGR4, SpGH101, in the absence of carbohydrate, and in complex with reaction products, inhibitor, and substrate analogues. Upon substrate binding, a tryptophan lid (residues 724-WNW-726) closes on the substrate. The closing of this lid fully engages the substrate in the active site with Asp-764 positioned directly beneath C1 of the sugar residue bound within the -1 subsite, consistent with its proposed role as the catalytic nucleophile. In all of the bound forms of the enzyme, however, the proposed catalytic acid/base residue was found to be too distant from the glycosidic oxygen (>4.3 Å) to serve directly as a general catalytic acid/base residue and thereby facilitate cleavage of the glycosidic bond. These same complexes, however, revealed a structurally conserved water molecule positioned between the catalytic acid/base and the glycosidic oxygen. On the basis of these structural observations we propose a new variation of the retaining glycoside hydrolase mechanism wherein the intervening water molecule enables a Grotthuss proton shuttle between Glu-796 and the glycosidic oxygen, permitting this residue to serve as the general acid/base catalytic residue.
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Affiliation(s)
- Katie J Gregg
- From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 3P6 and
| | - Michael D L Suits
- From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 3P6 and
| | - Lehua Deng
- the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - David J Vocadlo
- the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Alisdair B Boraston
- From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 3P6 and
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Mortimer JC, Faria-Blanc N, Yu X, Tryfona T, Sorieul M, Ng YZ, Zhang Z, Stott K, Anders N, Dupree P. An unusual xylan in Arabidopsis primary cell walls is synthesised by GUX3, IRX9L, IRX10L and IRX14. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 83:413-26. [PMID: 26043357 PMCID: PMC4528235 DOI: 10.1111/tpj.12898] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 05/22/2015] [Accepted: 05/26/2015] [Indexed: 05/04/2023]
Abstract
Xylan is a crucial component of many plant primary and secondary cell walls. However, the structure and function of xylan in the dicotyledon primary cell wall is not well understood. Here, we characterized a xylan that is specific to tissues enriched in Arabidopsis primary cell walls. Unlike previously described xylans, this xylan carries a pentose linked 1-2 to the α-1,2-d-glucuronic acid (GlcA) side chains on the β-1,4-Xyl backbone. The frequent and precisely regular spacing of GlcA substitutions every six xylosyl residues along the backbone is also unlike that previously observed in secondary cell wall xylan. Molecular genetics, in vitro assays, and expression data suggest that IRX9L, IRX10L and IRX14 are required for xylan backbone synthesis in primary cell wall synthesising tissues. IRX9 and IRX10 are not involved in the primary cell wall xylan synthesis but are functionally exchangeable with IRX9L and IRX10L. GUX3 is the only glucuronyltransferase required for the addition of the GlcA decorations on the xylan. The differences in xylan structure in primary versus secondary cell walls might reflect the different roles in cross-linking and interaction with other cell wall components.
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Affiliation(s)
- Jenny C Mortimer
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Joint BioEnergy InstituteBerkeley, CA, 94720, USA
| | - Nuno Faria-Blanc
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
| | - Xiaolan Yu
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
| | - Theodora Tryfona
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
| | - Mathias Sorieul
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
| | - Yao Z Ng
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
| | - Zhinong Zhang
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
| | - Katherine Stott
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
| | - Nadine Anders
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
| | - Paul Dupree
- Department of Biochemistry, University of CambridgeCambridge, CB2 1QW, UK
- *For Correspondence (e-mail )
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Aalbers F, Turkenburg JP, Davies GJ, Dijkhuizen L, Lammerts van Bueren A. Structural and Functional Characterization of a Novel Family GH115 4-O-Methyl-α-Glucuronidase with Specificity for Decorated Arabinogalactans. J Mol Biol 2015; 427:3935-46. [PMID: 26186997 DOI: 10.1016/j.jmb.2015.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/07/2015] [Accepted: 07/07/2015] [Indexed: 12/16/2022]
Abstract
Glycoside hydrolases are clustered into families based on amino acid sequence similarities, and belonging to a particular family can infer biological activity of an enzyme. Family GH115 contains α-glucuronidases where several members have been shown to hydrolyze terminal α-1,2-linked glucuronic acid and 4-O-methylated glucuronic acid from the plant cell wall polysaccharide glucuronoxylan. Other GH115 enzymes show no activity on glucuronoxylan, and therefore, it has been proposed that family GH115 may be a poly-specific family. In this study, we reveal that a putative periplasmic GH115 from the human gut symbiont Bacteroides thetaiotaomicron, BtGH115A, hydrolyzes terminal 4-O-methyl-glucuronic acid residues from decorated arabinogalactan isolated from acacia tree. The three-dimensional structure of BtGH115A reveals that BtGH115A has the same domain architecture as the other structurally characterized member of this family, BoAgu115A; however the position of the C-terminal module is altered with respect to each individual enzyme. Phylogenetic analysis of GH115 amino sequences divides the family into distinct clades that may distinguish different substrate specificities. Finally, we show that BtGH115A α-glucuronidase activity is necessary for the sequential digestion of branched galactans from acacia gum by a galactan-β-1,3-galactosidase from family GH43; however, while B. thetaiotaomicron grows on larch wood arabinogalactan, the bacterium is not able to metabolize acacia gum arabinogalactan, suggesting that BtGH115A is involved in degradation of arabinogalactan fragments liberated by other microbial species in the gastrointestinal tract.
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Affiliation(s)
- Friso Aalbers
- Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, The Netherlands
| | - Johan P Turkenburg
- York Structural Biology Laboratory, Department of Chemistry, University of York, YO10 5DD, York, United Kingdom
| | - Gideon J Davies
- York Structural Biology Laboratory, Department of Chemistry, University of York, YO10 5DD, York, United Kingdom
| | - Lubbert Dijkhuizen
- Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, The Netherlands
| | - Alicia Lammerts van Bueren
- Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, The Netherlands; York Structural Biology Laboratory, Department of Chemistry, University of York, YO10 5DD, York, United Kingdom.
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42
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Glycan complexity dictates microbial resource allocation in the large intestine. Nat Commun 2015; 6:7481. [PMID: 26112186 PMCID: PMC4491172 DOI: 10.1038/ncomms8481] [Citation(s) in RCA: 276] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 05/13/2015] [Indexed: 12/20/2022] Open
Abstract
The structure of the human gut microbiota is controlled primarily through the degradation of complex dietary carbohydrates, but the extent to which carbohydrate breakdown products are shared between members of the microbiota is unclear. We show here, using xylan as a model, that sharing the breakdown products of complex carbohydrates by key members of the microbiota, such as Bacteroides ovatus, is dependent on the complexity of the target glycan. Characterization of the extensive xylan degrading apparatus expressed by B. ovatus reveals that the breakdown of the polysaccharide by the human gut microbiota is significantly more complex than previous models suggested, which were based on the deconstruction of xylans containing limited monosaccharide side chains. Our report presents a highly complex and dynamic xylan degrading apparatus that is fine-tuned to recognize the different forms of the polysaccharide presented to the human gut microbiota. The human gut microbiota helps us to degrade complex dietary carbohydrates such as xylan and, in turn, the carbohydrate breakdown products control the structure of the microbiota. Here the authors characterize the xylan-degrading apparatus of a key member of the gut microbiota, Bacteroides ovatus.
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43
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Chong SL, Derba-Maceluch M, Koutaniemi S, Gómez LD, McQueen-Mason SJ, Tenkanen M, Mellerowicz EJ. Active fungal GH115 α-glucuronidase produced in Arabidopsis thaliana affects only the UX1-reactive glucuronate decorations on native glucuronoxylans. BMC Biotechnol 2015; 15:56. [PMID: 26084671 PMCID: PMC4472178 DOI: 10.1186/s12896-015-0154-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 04/27/2015] [Indexed: 12/22/2022] Open
Abstract
Background Expressing microbial polysaccharide-modifying enzymes in plants is an attractive approach to custom tailor plant lignocellulose and to study the importance of wall structures to plant development. Expression of α-glucuronidases in plants to modify the structures of glucuronoxylans has not been yet attempted. Glycoside hydrolase (GH) family 115 α-glucuronidases cleave the internal α-D-(4-O-methyl)glucopyranosyluronic acid ((Me)GlcA) from xylans or xylooligosaccharides. In this work, a GH115 α-glucuronidase from Schizophyllum commune, ScAGU115, was expressed in Arabidopsis thaliana and targeted to apoplast. The transgene effects on native xylans’ structures, plant development, and lignocellulose saccharification were evaluated and compared to those of knocked out glucuronyltransferases AtGUX1 and AtGUX2. Results The ScAGU115 extracted from cell walls of Arabidopsis was active on the internally substituted aldopentaouronic acid (XUXX). The transgenic plants did not show any change in growth or in lignocellulose saccharification. The cell wall (Me)GlcA and other non-cellulosic sugars, as well as the lignin content, remained unchanged. In contrast, the gux1gux2 double mutant showed a 70% decrease in (Me)GlcA to xylose molar ratio, and, interestingly, a 60% increase in the xylose content. Whereas ScAGU115-expressing plants exhibited a decreased signal in native secondary walls from the monoclonal antibody UX1 that recognizes (Me)GlcA on non-acetylated xylan, the signal was not affected after wall deacetylation. In contrast, gux1gux2 mutant was lacking UX1 signals in both native and deacetylated cell walls. This indicates that acetyl substitution on the xylopyranosyl residue carrying (Me)GlcA or on the neighboring xylopyranosyl residues may restrict post-synthetic modification of xylans by ScAGU115 in planta. Conclusions Active GH115 α-glucuronidase has been produced for the first time in plants. The cell wall–targeted ScAGU115 was shown to affect those glucuronate substitutions of xylan, which are accessible to UX1 antibody and constitute a small fraction in Arabidopsis, whereas majority of (Me)GlcA substitutions were resistant, most likely due to the shielding by acetyl groups. Plants expressing ScAGU115 did not show any defects under laboratory conditions indicating that the UX1 epitope of xylan is not essential under these conditions. Moreover the removal of the UX1 xylan epitope does not affect lignocellulose saccharification. Electronic supplementary material The online version of this article (doi:10.1186/s12896-015-0154-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sun-Li Chong
- Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 27, Helsinki, 00014, Finland.
| | - Marta Derba-Maceluch
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, 901-83, Sweden.
| | - Sanna Koutaniemi
- Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 27, Helsinki, 00014, Finland.
| | - Leonardo D Gómez
- Center for Novel Agricultural Products Department of Biology, University of York, York, YO10 5DD, UK.
| | - Simon J McQueen-Mason
- Center for Novel Agricultural Products Department of Biology, University of York, York, YO10 5DD, UK.
| | - Maija Tenkanen
- Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 27, Helsinki, 00014, Finland.
| | - Ewa J Mellerowicz
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, 901-83, Sweden.
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Sawhney N, Crooks C, St. John F, Preston JF. Transcriptomic analysis of xylan utilization systems in Paenibacillus sp. strain JDR-2. Appl Environ Microbiol 2015; 81:1490-501. [PMID: 25527555 PMCID: PMC4309694 DOI: 10.1128/aem.03523-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 12/13/2014] [Indexed: 11/20/2022] Open
Abstract
Xylans, including methylglucuronoxylans (MeGX(n)) and methylglucuronoarabinoxylans (MeGAXn), are the predominant polysaccharidesin hemicellulose fractions of dicots and monocots available for conversion to biofuels and chemicals. Paenibacillus sp. strain JDR-2 (Pjdr2) efficiently depolymerizes MeGX(n) and MeGAX(n) and assimilates the generated oligosaccharides, resulting in efficient saccharification and subsequent metabolism of these polysaccharides. A xylan utilization regulon encoding a cellassociated GH10 (glycoside hydrolase family 10) endoxylanase, transcriptional regulators, ABC (ATP binding cassette) transporters, an intracellular GH67 -glucuronidase, and other glycoside hydrolases contributes to complete metabolism. This GH10/GH67 system has been proposed to account for preferential utilization of xylans compared to free oligo- and monosaccharides. To identify additional genes contributing to MeGX(n) and MeGAXn utilization, the transcriptome of Pjdr2 has been sequenced following growth on each of these substrates as well as xylose and arabinose. Increased expression of genes with different substrates identified pathways common or unique to the utilization of MeGX(n) or MeGAX(n). Coordinate upregulation of genes comprising the GH10/GH67 xylan utilization regulon is accompanied with upregulation of genes encoding a GH11 endoxylanase and a GH115 -glucuronidase, providing evidence for a novel complementary pathway for processing xylans. Elevated expression of genes encoding a GH43 arabinoxylan arabinofuranohydrolase and an arabinose ABC transporter on MeGAX(n) but not on MeGX(n) supports a process in which arabinose may be removed extracellularly followed by its rapid assimilation.Further development of Pjdr2 for direct conversion of xylans to targeted products or introduction of these systems into fermentative strains of related bacteria may lead to biocatalysts for consolidated bioprocessing of hemicelluloses released from lignocellulose.
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Affiliation(s)
- Neha Sawhney
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Casey Crooks
- U.S. Department of Agriculture, U.S. Forest Service, Forest Products Laboratory, Madison, Wisconsin, USA
| | - Franz St. John
- U.S. Department of Agriculture, U.S. Forest Service, Forest Products Laboratory, Madison, Wisconsin, USA
| | - James F. Preston
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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Derba-Maceluch M, Awano T, Takahashi J, Lucenius J, Ratke C, Kontro I, Busse-Wicher M, Kosik O, Tanaka R, Winzéll A, Kallas Å, Leśniewska J, Berthold F, Immerzeel P, Teeri TT, Ezcurra I, Dupree P, Serimaa R, Mellerowicz EJ. Suppression of xylan endotransglycosylase PtxtXyn10A affects cellulose microfibril angle in secondary wall in aspen wood. THE NEW PHYTOLOGIST 2015; 205:666-81. [PMID: 25307149 DOI: 10.1111/nph.13099] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/25/2014] [Indexed: 05/02/2023]
Abstract
Certain xylanases from family GH10 are highly expressed during secondary wall deposition, but their function is unknown. We carried out functional analyses of the secondary-wall specific PtxtXyn10A in hybrid aspen (Populus tremula × tremuloides). PtxtXyn10A function was analysed by expression studies, overexpression in Arabidopsis protoplasts and by downregulation in aspen. PtxtXyn10A overexpression in Arabidopsis protoplasts resulted in increased xylan endotransglycosylation rather than hydrolysis. In aspen, the enzyme was found to be proteolytically processed to a 68 kDa peptide and residing in cell walls. Its downregulation resulted in a corresponding decrease in xylan endotransglycosylase activity and no change in xylanase activity. This did not alter xylan molecular weight or its branching pattern but affected the cellulose-microfibril angle in wood fibres, increased primary growth (stem elongation, leaf formation and enlargement) and reduced the tendency to form tension wood. Transcriptomes of transgenic plants showed downregulation of tension wood related genes and changes in stress-responsive genes. The data indicate that PtxtXyn10A acts as a xylan endotransglycosylase and its main function is to release tensional stresses arising during secondary wall deposition. Furthermore, they suggest that regulation of stresses in secondary walls plays a vital role in plant development.
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Affiliation(s)
- Marta Derba-Maceluch
- Department of Forest Genetics and Plant Physiology, SLU, Umeå Plant Science Centre (UPSC), Umeå, Sweden
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Molecular modeling and MM-PBSA free energy analysis of endo-1,4-β-xylanase from Ruminococcus albus 8. Int J Mol Sci 2014; 15:17284-303. [PMID: 25264743 PMCID: PMC4227162 DOI: 10.3390/ijms151017284] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/11/2014] [Accepted: 09/15/2014] [Indexed: 11/16/2022] Open
Abstract
Endo-1,4-β-xylanase (EC 3.2.1.8) is the enzyme from Ruminococcus albus 8 (R. albus 8) (Xyn10A), and catalyzes the degradation of arabinoxylan, which is a major cell wall non-starch polysaccharide of cereals. The crystallographic structure of Xyn10A is still unknown. For this reason, we report a computer-assisted homology study conducted to build its three-dimensional structure based on the known sequence of amino acids of this enzyme. In this study, the best similarity was found with the Clostridium thermocellum (C. thermocellum) N-terminal endo-1,4-β-D-xylanase 10 b. Following the 100 ns molecular dynamics (MD) simulation, a reliable model was obtained for further studies. Molecular Mechanics/Poisson-Boltzmann Surface Area (MM-PBSA) methods were used for the substrate xylotetraose having the reactive sugar, which was bound in the -1 subsite of Xyn10A in the 4C1 (chair) and 2SO (skew boat) ground state conformations. According to the simulations and free energy analysis, Xyn10A binds the substrate with the -1 sugar in the 2SO conformation 39.27 kcal·mol(-1) tighter than the substrate with the sugar in the 4C1 conformation. According to the Xyn10A-2SO Xylotetraose (X4(sb) interaction energies, the most important subsite for the substrate binding is subsite -1. The results of this study indicate that the substrate is bound in a skew boat conformation with Xyn10A and the -1 sugar subsite proceeds from the 4C1 conformation through 2SO to the transition state. MM-PBSA free energy analysis indicates that Asn187 and Trp344 in subsite -1 may an important residue for substrate binding. Our findings provide fundamental knowledge that may contribute to further enhancement of enzyme performance through molecular engineering.
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Elucidation of the molecular basis for arabinoxylan-debranching activity of a thermostable family GH62 α-l-arabinofuranosidase from Streptomyces thermoviolaceus. Appl Environ Microbiol 2014; 80:5317-29. [PMID: 24951792 DOI: 10.1128/aem.00685-14] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Xylan-debranching enzymes facilitate the complete hydrolysis of xylan and can be used to alter xylan chemistry. Here, the family GH62 α-l-arabinofuranosidase from Streptomyces thermoviolaceus (SthAbf62A) was shown to have a half-life of 60 min at 60°C and the ability to cleave α-1,3 l-arabinofuranose (l-Araf) from singly substituted xylopyranosyl (Xylp) backbone residues in wheat arabinoxylan; low levels of activity on arabinan as well as 4-nitrophenyl α-l-arabinofuranoside were also detected. After selective removal of α-1,3 l-Araf substituents from disubstituted Xylp residues present in wheat arabinoxylan, SthAbf62A could also cleave the remaining α-1,2 l-Araf substituents, confirming the ability of SthAbf62A to remove α-l-Araf residues that are (1→2) and (1→3) linked to monosubstituted β-d-Xylp sugars. Three-dimensional structures of SthAbf62A and its complex with xylotetraose and l-arabinose confirmed a five-bladed β-propeller fold and revealed a molecular Velcro in blade V between the β1 and β21 strands, a disulfide bond between Cys27 and Cys297, and a calcium ion coordinated in the central channel of the fold. The enzyme-arabinose complex structure further revealed a narrow and seemingly rigid l-arabinose binding pocket situated at the center of one side of the β propeller, which stabilized the arabinofuranosyl substituent through several hydrogen-bonding and hydrophobic interactions. The predicted catalytic amino acids were oriented toward this binding pocket, and the catalytic essentiality of Asp53 and Glu213 was confirmed by site-specific mutagenesis. Complex structures with xylotetraose revealed a shallow cleft for xylan backbone binding that is open at both ends and comprises multiple binding subsites above and flanking the l-arabinose binding pocket.
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