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Kalenborn S, Zühlke D, Riedel K, Amann RI, Harder J. Proteomic insight into arabinogalactan utilization by particle-associated Maribacter sp. MAR_2009_72. FEMS Microbiol Ecol 2024; 100:fiae045. [PMID: 38569650 PMCID: PMC11036162 DOI: 10.1093/femsec/fiae045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/13/2024] [Accepted: 04/02/2024] [Indexed: 04/05/2024] Open
Abstract
Arabinose and galactose are major, rapidly metabolized components of marine particulate and dissolved organic matter. In this study, we observed for the first time large microbiomes for the degradation of arabinogalactan and report a detailed investigation of arabinogalactan utilization by the flavobacterium Maribacter sp. MAR_2009_72. Cellular extracts hydrolysed arabinogalactan in vitro. Comparative proteomic analyses of cells grown on arabinogalactan, arabinose, galactose, and glucose revealed the expression of specific proteins in the presence of arabinogalactan, mainly glycoside hydrolases (GH). Extracellular glycan hydrolysis involved five alpha-l-arabinofuranosidases affiliating with glycoside hydrolase families 43 and 51, four unsaturated rhamnogalacturonylhydrolases (GH105) and a protein with a glycoside hydrolase family-like domain. We detected expression of three induced TonB-dependent SusC/D transporter systems, one SusC, and nine glycoside hydrolases with a predicted periplasmatic location. These are affiliated with the families GH3, GH10, GH29, GH31, GH67, GH78, and GH115. The genes are located outside of and within canonical polysaccharide utilization loci classified as specific for arabinogalactan, for galactose-containing glycans, and for arabinose-containing glycans. The breadth of enzymatic functions expressed in Maribacter sp. MAR_2009_72 as response to arabinogalactan from the terrestrial plant larch suggests that Flavobacteriia are main catalysts of the rapid turnover of arabinogalactans in the marine environment.
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Affiliation(s)
- Saskia Kalenborn
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Celsiusstr. 1, D-28359 Bremen, Germany
| | - Daniela Zühlke
- Department for Microbial Physiology and Molecular Biology, University of Greifswald, Felix-Hausdorff-Str. 8, D-17489 Greifswald, Germany
| | - Katharina Riedel
- Department for Microbial Physiology and Molecular Biology, University of Greifswald, Felix-Hausdorff-Str. 8, D-17489 Greifswald, Germany
| | - Rudolf I Amann
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Celsiusstr. 1, D-28359 Bremen, Germany
| | - Jens Harder
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Celsiusstr. 1, D-28359 Bremen, Germany
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2
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Garbelotti CV, Grandis A, Crevelin E, Buckeridge MS, de Moraes LAB, Ward RJ. Glycomic profiling identifies key-structural differences in three arabinoxylan fractions from sugarcane culms. Carbohydr Polym 2023; 310:120694. [PMID: 36925235 DOI: 10.1016/j.carbpol.2023.120694] [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: 11/21/2022] [Revised: 02/03/2023] [Accepted: 02/08/2023] [Indexed: 02/13/2023]
Abstract
Sugarcane is an important food and bioenergy crop, and although the residual biomass is potentially available for biorefinery and biofuels production the complex plant cell wall matrix requires pretreatment prior to enzymatic hydrolysis. Arabinoxylans require multiple enzymes for xylose backbone and saccharide side-branch hydrolysis to release xylooligosaccharides and pentoses. The effect of arabinoxylan structure on xylooligosaccharide release by combinations of up to five xylanolytic enzymes was studied using three arabinoxylan fractions extracted from sugarcane culms by sodium chlorite, DMSO and alkaline treatments. Reducing sugar release and LC-MS detection with chemometric analysis identified different xylooligosaccharide profiles between extracts following enzyme treatments. The position and degree of side-branch decorations are determinants of enzyme activity and xylooligosaccharide diversity with the alkaline and post‑sodium chlorite extracts as the most accessible and most recalcitrant, respectively, indicating acetyl substituents as a major recalcitrance factor. The complex xylooligosaccharide profile with the DMSO extract suggests regions with different levels of branching. Chemometric analysis identified GH10 xylanase hydrolysis products that act as substrates for other enzymes, such as α-glucuronidase. The strategy reported here can identify specific enzyme combinations to overcome barriers for biomass processing such as pretreatment selection, recalcitrance to enzyme digestion and optimization of reducing sugar release.
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Affiliation(s)
- Carolina Victal Garbelotti
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP CEP 14040-901, Brazil.
| | - Adriana Grandis
- Laboratório de Fisiologia Ecológica de Plantas do Instituto de Biociências da Universidade de São Paulo, São Paulo, SP CEP 05508-090, Brazil
| | - Eduardo Crevelin
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP CEP 14040-901, Brazil.
| | - Marcos Silveira Buckeridge
- Laboratório de Fisiologia Ecológica de Plantas do Instituto de Biociências da Universidade de São Paulo, São Paulo, SP CEP 05508-090, Brazil
| | - Luiz Alberto Beraldo de Moraes
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP CEP 14040-901, Brazil.
| | - Richard John Ward
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP CEP 14040-901, Brazil.
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3
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Pentari C, Zerva A, Dimarogona M, Topakas E. The xylobiohydrolase activity of a GH30 xylanase on natively acetylated xylan may hold the key for the degradation of recalcitrant xylan. Carbohydr Polym 2023; 305:120527. [PMID: 36737185 DOI: 10.1016/j.carbpol.2022.120527] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 12/22/2022] [Accepted: 12/29/2022] [Indexed: 01/11/2023]
Abstract
Acetyl substitutions are common on the hemicellulosic structures of lignocellulose, which up until recently were known to inhibit xylanase activity. Emerging data, however, suggest that xylanases are able to accommodate acetyl side-groups within their catalytic site. In the present work, a fungal GH30 xylanase from Thermothelomyces thermophila, namely TtXyn30A, was shown to release acetylated xylobiose when acting on pretreated lignocellulosic substrate. The released disaccharides could be acetylated at the 2-OH, 3-OH or both positions of the non-reducing end xylose, but the existence of the acetylation on the reducing end cannot be excluded. The synergy of TtXyn30A with acetyl esterases indicates that particular subsites within its active site cannot tolerate acetylated xylopyranose residues. Molecular docking showed that acetyl group can be accommodated on the 2- or 3-OH position of the non-reducing end xylose, unlike the reducing-end xylose (subsite -1), where only 3-OH decoration can be accommodated. Such insight into the catalytic activity of TtXyn30A could contribute to a better understanding of its biological role and thus lead to a more sufficient biotechnological utilization.
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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
| | - Anastasia Zerva
- 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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4
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Li X, Dilokpimol A, Kabel MA, de Vries RP. Fungal xylanolytic enzymes: Diversity and applications. BIORESOURCE TECHNOLOGY 2022; 344:126290. [PMID: 34748977 DOI: 10.1016/j.biortech.2021.126290] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 05/26/2023]
Abstract
As important polysaccharide degraders in nature, fungi can diversify their extensive set of carbohydrate-active enzymes to survive in ecological habitats of various composition. Among these enzymes, xylanolytic ones can efficiently and sustainably degrade xylans into (fermentable) monosaccharides to produce valuable chemicals or fuels from, for example relevant for upgrading agro-food industrial side streams. Moreover, xylanolytic enzymes are being used in various industrial applications beyond biomass saccharification, e.g. food, animal feed, biofuel, pulp and paper. As a reference for researchers working in related areas, this review summarized the current knowledge on substrate specificity of xylanolytic enzymes from different families of the Carbohydrate-Active enZyme database. Additionally, the diversity of enzyme sets in fungi were discussed by comparing the number of genes encoding xylanolytic enzymes in selected fungal genomes. Finally, to support bio-economy, the current applications of fungal xylanolytic enzymes in industry were reviewed.
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Affiliation(s)
- Xinxin Li
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Adiphol Dilokpimol
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Mirjam A Kabel
- Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
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5
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Salem H, Kirsch R, Pauchet Y, Berasategui A, Fukumori K, Moriyama M, Cripps M, Windsor D, Fukatsu T, Gerardo NM. Symbiont Digestive Range Reflects Host Plant Breadth in Herbivorous Beetles. Curr Biol 2020; 30:2875-2886.e4. [PMID: 32502409 DOI: 10.1016/j.cub.2020.05.043] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 04/05/2020] [Accepted: 05/12/2020] [Indexed: 02/07/2023]
Abstract
Numerous adaptations are gained in light of a symbiotic lifestyle. Here, we investigated the obligate partnership between tortoise leaf beetles (Chrysomelidae: Cassidinae) and their pectinolytic Stammera symbionts to detail how changes to the bacterium's streamlined metabolic range can shape the digestive physiology and ecological opportunity of its herbivorous host. Comparative genomics of 13 Stammera strains revealed high functional conservation, highlighted by the universal presence of polygalacturonase, a primary pectinase targeting nature's most abundant pectic class, homogalacturonan (HG). Despite this conservation, we unexpectedly discovered a disparate distribution for rhamnogalacturonan lyase, a secondary pectinase hydrolyzing the pectic heteropolymer, rhamnogalacturonan I (RG-I). Consistent with the annotation of rhamnogalacturonan lyase in Stammera, cassidines are able to depolymerize RG-I relative to beetles whose symbionts lack the gene. Given the omnipresence of HG and RG-I in foliage, Stammera that encode pectinases targeting both substrates allow their hosts to overcome a greater diversity of plant cell wall polysaccharides and maximize access to the nutritionally rich cytosol. Possibly facilitated by their symbionts' expanded digestive range, cassidines additionally endowed with rhamnogalacturonan lyase appear to utilize a broader diversity of angiosperms than those beetles whose symbionts solely supplement polygalacturonase. Our findings highlight how symbiont metabolic diversity, in concert with host adaptations, may serve as a potential source of evolutionary innovations for herbivorous lineages.
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Affiliation(s)
- Hassan Salem
- Department of Biology, Emory University, Atlanta, GA 30322, USA; National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA; Mutualisms Research Group, Max Planck Institute for Developmental Biology, Tübingen 72076, Germany.
| | - Roy Kirsch
- Department of Entomology, Max Planck Institute for Chemical Ecology, Jena 07745, Germany
| | - Yannick Pauchet
- Department of Entomology, Max Planck Institute for Chemical Ecology, Jena 07745, Germany
| | | | - Kayoko Fukumori
- National Institute for Advanced Industrial Science and Technology, Tsukuba 305-8566, Japan
| | - Minoru Moriyama
- National Institute for Advanced Industrial Science and Technology, Tsukuba 305-8566, Japan
| | - Michael Cripps
- AgResearch, Lincoln Research Centre, Lincoln 7608, New Zealand
| | - Donald Windsor
- Smithsonian Tropical Research Institute, Panama City 0843-03092, Panama
| | - Takema Fukatsu
- National Institute for Advanced Industrial Science and Technology, Tsukuba 305-8566, Japan
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6
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Monrad RN, Eklöf J, Krogh KBRM, Biely P. Glucuronoyl esterases: diversity, properties and biotechnological potential. A review. Crit Rev Biotechnol 2018; 38:1121-1136. [PMID: 29739247 DOI: 10.1080/07388551.2018.1468316] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Glucuronoyl esterases (GEs) belonging to the carbohydrate esterase family 15 (CE15) are involved in microbial degradation of lignocellulosic plant materials. GEs are capable of degrading complex polymers of lignin and hemicellulose cleaving ester bonds between glucuronic acid residues in xylan and lignin alcohols. GEs promote separation of lignin, hemicellulose and cellulose which is crucial for efficient utilization of biomass as an energy source and feedstock for further processing into products or chemicals. Genes encoding GEs are found in both fungi and bacteria, but, so far, bacterial GEs are essentially unexplored, and despite being discovered >10 years ago, only a limited number of GEs have been characterized. The first laboratory scale example of improved xylose and glucuronic acid release by the synergistic action of GE with cellulolytic enzymes was only reported recently (improved C5 sugar and glucuronic acid yields) and, until now, not much is known about their biotechnology potential. In this review, we discuss the diversity, structure and properties of microbial GEs and consider the status of their action on natural substrates and in biological systems in relation to their future industrial use.
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Affiliation(s)
| | | | | | - Peter Biely
- b Institute of Chemistry, Slovak Academy of Sciences , Bratislava , Slovak Republic
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7
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Yagi H, Maehara T, Tanaka T, Takehara R, Teramoto K, Yaoi K, Kaneko S. 4- O-Methyl Modifications of Glucuronic Acids in Xylans Are Indispensable for Substrate Discrimination by GH67 α-Glucuronidase from Bacillus halodurans C-125. J Appl Glycosci (1999) 2017; 64:115-121. [PMID: 34354504 PMCID: PMC8056927 DOI: 10.5458/jag.jag.jag-2017_016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 10/18/2017] [Indexed: 10/29/2022] Open
Abstract
A GH67 α-glucuronidase gene derived from Bacillus halodurans C-125 was expressed in E. coli to obtain a recombinant enzyme (BhGlcA67). Using the purified enzyme, the enzymatic properties and substrate specificities of the enzyme were investigated. BhGlcA67 showed maximum activity at pH 5.4 and 45 °C. When BhGlcA67 was incubated with birchwood, oat spelts, and cotton seed xylan, the enzyme did not release any glucuronic acid or 4-O-methyl-glucuronic acid from these substrates. BhGlcA67 acted only on 4-O-methyl-α-D-glucuronopyranosyl-(1→2)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranose (MeGlcA3Xyl3), which has a glucuronic acid side chain with a 4-O-methyl group located at its non-reducing end, but did not on β-D-xylopyranosyl-(1→4)-[4-O-methyl-α-D-glucuronopyranosyl-(l→2)]-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylop- yranose (MeGlcA3Xyl4) and α-D-glucuronopyranosyl-(l→2)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranose (GlcA3Xyl3). The environment for recognizing the 4-O-methyl group of glucuronic acid was observed in all the crystal structures of reported GH67 glucuronidases, and the amino acids for discriminating the 4-O-methyl group of glucuronic acid were widely conserved in the primary sequences of the GH67 family, suggesting that the 4-O-methyl group is critical for the activities of the GH67 family.
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Affiliation(s)
- Haruka Yagi
- 1 Department of Subtropical Biochemistry and Biotechnology, Faculty of Agriculture, University of the Ryukyus
| | - Tomoko Maehara
- 2 Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Tsuyoshi Tanaka
- 1 Department of Subtropical Biochemistry and Biotechnology, Faculty of Agriculture, University of the Ryukyus.,3 The United Graduate School of Agricultural Sciences, Kagoshima University
| | - Ryo Takehara
- 1 Department of Subtropical Biochemistry and Biotechnology, Faculty of Agriculture, University of the Ryukyus
| | - Koji Teramoto
- 1 Department of Subtropical Biochemistry and Biotechnology, Faculty of Agriculture, University of the Ryukyus
| | - Katsuro Yaoi
- 2 Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Satoshi Kaneko
- 1 Department of Subtropical Biochemistry and Biotechnology, Faculty of Agriculture, University of the Ryukyus
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8
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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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9
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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: 169] [Impact Index Per Article: 21.1] [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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10
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Gong W, Zhang H, Tian L, Liu S, Wu X, Li F, Wang L. Determination of the modes of action and synergies of xylanases by analysis of xylooligosaccharide profiles over time using fluorescence-assisted carbohydrate electrophoresis. Electrophoresis 2016; 37:1640-50. [PMID: 27060349 DOI: 10.1002/elps.201600041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/21/2016] [Accepted: 03/23/2016] [Indexed: 01/06/2023]
Abstract
The structure of xylan, which has a 1,4-linked β-xylose backbone with various substituents, is much more heterogeneous and complex than that of cellulose. Because of this, complete degradation of xylan needs a large number of enzymes that includes GH10, GH11, and GH3 family xylanases together with auxiliary enzymes. Fluorescence-assisted carbohydrate electrophoresis (FACE) is able to accurately differentiate unsubstituted and substituted xylooligosaccharides (XOS) in the heterogeneous products generated by different xylanases and allows changes in concentrations of specific XOS to be analyzed quantitatively. Based on a quantitative analysis of XOS profiles over time using FACE, we have demonstrated that GH10 and GH11 family xylanases immediately degrade xylan into sizeable XOS, which are converted into smaller XOS in a much lower speed. The shortest substituted XOS produced by hydrolysis of the substituted xylan backbone by GH10 and GH11 family xylanases were MeGlcA(2) Xyl3 and MeGlcA(2) Xyl4 , respectively. The unsubstituted xylan backbone was degraded into xylose, xylobiose, and xylotriose by both GH10 and GH11 family xylanases; the product profiles are not family-specific but, instead, depend on different subsite binding affinities in the active sites of individual enzymes. Synergystic action between xylanases and β-xylosidase degraded MeGlcA(2) Xyl4 into xylose and MeGlcA(2) Xyl3 but further degradation of MeGlcA(2) Xyl3 required additional enzymes. Synergy between xylanases and β-xylosidase was also found to significantly accelerate the conversion of XOS into xylose.
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Affiliation(s)
- Weili Gong
- The State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong, P. R. China
| | - Huaiqiang Zhang
- The State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong, P. R. China
| | - Li Tian
- The State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong, P. R. China
| | - Shijia Liu
- Taishan College, Shandong University, Jinan, Shandong, P. R. China
| | - Xiuyun Wu
- The State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong, P. R. China
| | - Fuli Li
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Lushan Wang
- The State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong, P. R. China
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11
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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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12
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Septiningrum K, Ohi H, Waeonukul R, Pason P, Tachaapaikoon C, Ratanakhanokchai K, Sermsathanaswadi J, Deng L, Prawitwong P, Kosugi A. The GH67 α-glucuronidase of Paenibacillus curdlanolyticus B-6 removes hexenuronic acid groups and facilitates biodegradation of the model xylooligosaccharide hexenuronosyl xylotriose. Enzyme Microb Technol 2015; 71:28-35. [PMID: 25765307 DOI: 10.1016/j.enzmictec.2015.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 11/25/2014] [Accepted: 01/19/2015] [Indexed: 10/24/2022]
Abstract
4-O-Methylglucuronic acid (MeGlcA) side groups attached to the xylan backbone through α-1,2 linkages are converted to hexenuronic acid (HexA) during alkaline pulping. α-Glucuronidase (EC 3.2.1.139) hydrolyzes 1,2-linked MeGlcA from xylooligosaccharides. To determine whether α-glucuronidase can also hydrolyze HexA-decorated xylooligosaccharides, a gene encoding α-glucuronidase (AguA) was cloned from Paenibacillus curdlanolyticus B-6. The purified protein degraded hexenuronosyl xylotriose (ΔX3), a model substrate prepared from kraft pulp. AguA released xylotriose and HexA from ΔX3, but the Vmax and kcat values for ΔX3 were lower than those for MeGlcA, indicating that HexA side groups may affect the hydrolytic activity. To explore the potential for biological bleaching, ΔX3 degradation was performed using intracellular extract from P. curdlanolyticus B-6. The intracellular extract, with synergistic α-glucuronidase and β-xylosidase activities, degraded ΔX3 to xylose and HexA. These results indicate that α-glucuronidase can be used to remove HexA from ΔX3 derived from pulp, reducing the need for chemical treatments in the pulping process.
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Affiliation(s)
- Krisna Septiningrum
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Hiroshi Ohi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Rattiya Waeonukul
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand
| | - Patthra Pason
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand
| | - Chakrit Tachaapaikoon
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand
| | - Khanok Ratanakhanokchai
- School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand
| | - Junjarus Sermsathanaswadi
- Department of Chemical Technology, Faculty of Science and Technology, Suan Dusit Rajabhat University, 295 Rajasrima Road, Dusit, Bangkok 10300, Thailand
| | - Lan Deng
- Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Panida Prawitwong
- Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Akihiko Kosugi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
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13
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Rosa L, Ravanal MC, Mardones W, Eyzaguirre J. Characterization of a recombinant α-glucuronidase from Aspergillus fumigatus. Fungal Biol 2013; 117:380-7. [DOI: 10.1016/j.funbio.2013.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 03/05/2013] [Accepted: 04/07/2013] [Indexed: 11/16/2022]
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14
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Abstract
α-Glucuronidase enzymes play an essential role in the full enzymatic hydrolysis of hemicellulose. Up to this point, all genes encoding α-glucuronidase enzymes have been cloned from individual, pure culture strains. Using a high-throughput screening strategy, we have isolated the first α-glucuronidase gene (rum630-AG) from a mixed population of microorganisms. The gene was subcloned into a prokaryotic vector, and the enzyme was overexpressed and biochemically characterized. The RUM630-AG enzyme had optimum activity at pH 6.5 and 40 °C. When birchwood xylan was used as substrate, the RUM630-AG functioned synergistically with an endoxylanase enzyme to hydrolyze the substrate.
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15
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Chong SL, Battaglia E, Coutinho PM, Henrissat B, Tenkanen M, de Vries RP. The α-glucuronidase Agu1 from Schizophyllum commune is a member of a novel glycoside hydrolase family (GH115). Appl Microbiol Biotechnol 2011; 90:1323-32. [DOI: 10.1007/s00253-011-3157-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 01/28/2011] [Accepted: 01/29/2011] [Indexed: 10/18/2022]
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16
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Inverting character of family GH115 α-glucuronidases. FEBS Lett 2010; 584:4063-8. [DOI: 10.1016/j.febslet.2010.08.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 07/21/2010] [Accepted: 08/19/2010] [Indexed: 11/21/2022]
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17
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Yeoman CJ, Han Y, Dodd D, Schroeder CM, Mackie RI, Cann IKO. Thermostable enzymes as biocatalysts in the biofuel industry. ADVANCES IN APPLIED MICROBIOLOGY 2010; 70:1-55. [PMID: 20359453 DOI: 10.1016/s0065-2164(10)70001-0] [Citation(s) in RCA: 173] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Lignocellulose is the most abundant carbohydrate source in nature and represents an ideal renewable energy source. Thermostable enzymes that hydrolyze lignocellulose to its component sugars have significant advantages for improving the conversion rate of biomass over their mesophilic counterparts. We review here the recent literature on the development and use of thermostable enzymes for the depolymerization of lignocellulosic feedstocks for biofuel production. Furthermore, we discuss the protein structure, mechanisms of thermostability, and specific strategies that can be used to improve the thermal stability of lignocellulosic biocatalysts.
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Affiliation(s)
- Carl J Yeoman
- Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
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18
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A novel family of hemicellulolytic alpha-glucuronidase. FEBS Lett 2009; 583:1457-62. [PMID: 19344716 DOI: 10.1016/j.febslet.2009.03.057] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 03/11/2009] [Accepted: 03/25/2009] [Indexed: 11/22/2022]
Abstract
Investigation of the xylanolytic enzyme system of the xylose-fermenting yeast Pichia stipitis resulted in the discovery of an extracellular alpha-glucuronidase efficiently debranching hardwood glucuronoxylan. This activity is not exhibited by more extensively investigated alpha-glucuronidases of glycoside hydrolase (GH) family 67, operating on substrates in which the uronic acid is linked to the non-reducing xylopyranosyl residues of main chain fragments. The N-terminus of the purified enzyme corresponded exactly to the P. stipitis gene ABN67901 coding for a protein of unknown function. BLAST search revealed the presence of similar genes in genomes of other microorganisms. These results lead to the emergence of a new family of alpha-glucuronidases.
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19
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Lee CC, Wagschal K, Kibblewhite-Accinelli RE, Orts WJ, Robertson GH, Wong DWS. An α-Glucuronidase Enzyme Activity Assay Adaptable for Solid Phase Screening. Appl Biochem Biotechnol 2008; 155:314-20. [DOI: 10.1007/s12010-008-8408-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 10/22/2008] [Indexed: 11/28/2022]
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20
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Simultaneous production of endo-β-1,4-xylanase and branched xylooligosaccharides by Thermomyces lanuginosus. J Biotechnol 2008; 137:34-43. [DOI: 10.1016/j.jbiotec.2008.07.1789] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 06/25/2008] [Accepted: 07/07/2008] [Indexed: 11/20/2022]
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21
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Spániková S, Biely P. Glucuronoyl esterase--novel carbohydrate esterase produced by Schizophyllum commune. FEBS Lett 2006; 580:4597-601. [PMID: 16876163 DOI: 10.1016/j.febslet.2006.07.033] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 07/12/2006] [Accepted: 07/13/2006] [Indexed: 11/23/2022]
Abstract
The cellulolytic system of the wood-rotting fungus Schizophyllum commune contains an esterase that hydrolyzes methyl ester of 4-O-methyl-d-glucuronic acid. The enzyme, called glucuronoyl esterase, was purified to electrophoretic homogeneity from a cellulose-spent culture fluid. Its substrate specificity was examined on a number of substrates of other carbohydrate esterases such as acetylxylan esterase, feruloyl esterase and pectin methylesterase. The glucuronoyl esterase attacks exclusively the esters of MeGlcA. The methyl ester of free or glycosidically linked MeGlcA was not hydrolysed by other carbohydrate esterases. The results suggest that we have discovered a new type of carbohydrate esterase that might be involved in disruption of ester linkages connecting hemicellulose and lignin in plant cell walls.
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Affiliation(s)
- Silvia Spániková
- Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 84538 Bratislava, Slovakia
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22
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Chávez R, Bull P, Eyzaguirre J. The xylanolytic enzyme system from the genus Penicillium. J Biotechnol 2006; 123:413-33. [PMID: 16569456 DOI: 10.1016/j.jbiotec.2005.12.036] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2005] [Revised: 12/06/2005] [Accepted: 12/23/2005] [Indexed: 11/22/2022]
Abstract
In nature, there are numerous microorganisms that efficiently degrade xylan, a major component of lignocellulose. In particular, filamentous fungi have demonstrated a great capability for secreting a wide range of xylanases, being the genus Aspergillus and Trichoderma the most extensively studied and reviewed among the xylan-producing fungi. However, an important amount of information about the production and genetics of xylanases from fungi of the genus Penicillium has accumulated in recent years. A great number of Penicillia are active producers of xylanolytic enzymes, and the use of xylanases from these species has acquired growing importance in biotechnological applications. This review summarizes our current knowledge about the properties, genetics, expression and biotechnological potential of xylanases from the genus Penicillium.
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Affiliation(s)
- Renato Chávez
- Unidad de Biotecnología, Instituto de Investigaciones Agropecuarias (INIA), CRI-Carillanca, Temuco, Chile
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23
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Kolenová K, Vrsanská M, Biely P. Mode of action of endo-β-1,4-xylanases of families 10 and 11 on acidic xylooligosaccharides. J Biotechnol 2006; 121:338-45. [PMID: 16157409 DOI: 10.1016/j.jbiotec.2005.08.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Revised: 07/22/2005] [Accepted: 08/02/2005] [Indexed: 10/25/2022]
Abstract
Mode of action of endo-beta-1,4-xylanases (EXs) of glycoside hydrolase families 10 (GH-10) and 11 (GH-11) was examined on various acidic xylooligosaccharides. As expected, none of the enzymes of GH-10 cleaved aldotetraouronic acid (MeGlcA3Xyl3), which is the shortest acidic product of the action of these EXs on glucuronoxylan. Surprisingly, aldopentaouronic acid (MeGlcA3Xyl4) was also not attacked. Only aldohexaouronic acid (MeGlcA3Xyl5) served as a substrate and was cleaved to xylobiose and aldotetraouronic acid. These results suggested that binding of xylopyranosyl residue in the -2 subsite is prerequisite for cleavage of the linkage adjacent to the xylopyranosyl unit carrying MeGlcA. EXs of family GH-11 cleaved neither aldotetraouronic acid, nor aldopentaouronic acid, which is in agreement with their action on glucuronoxylan. Aldohexaouronic acid was cleaved to aldopentaouronic acid and xylobiose without any production of xylose, suggesting that a xylosyl transfer reaction is involved in the degradation of the substrate by EXs of GH-11.
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Affiliation(s)
- Katarína Kolenová
- Slovak Academy of Sciences, Institute of Chemistry, Dúbravská cesta 9, 84538 Bratislava, Slovakia.
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24
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Klug-Santner BG, Schnitzhofer W, Vrsanská M, Weber J, Agrawal PB, Nierstrasz VA, Guebitz GM. Purification and characterization of a new bioscouring pectate lyase from Bacillus pumilus BK2. J Biotechnol 2006; 121:390-401. [PMID: 16168510 DOI: 10.1016/j.jbiotec.2005.07.019] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Revised: 07/08/2005] [Accepted: 07/14/2005] [Indexed: 10/25/2022]
Abstract
An alkalophilic bacterium was isolated based on the potential of extra-cellular enzymes for bioscouring. The bacterium was identified as a new strain of Bacillus pumilus BK2 producing an extra-cellular endo-pectate lyase PL (EC 4.2.2.2). PL was purified to homogeneity in three steps and has a molecular mass of 37.3+/-4.8 kDa as determined by SDS-PAGE and an isoelectric point of pH 8.5. Peptide mass mapping by nano-LC-MS of PL revealed 15% homology with a pectate lyase from Bacillus sp. The pectate lyase exhibited optimum activity at pH 8.5 and around 70 degrees C in Tris/HCl buffer. It showed a half-life at 30 degrees C of more than 75 h. Stability decreased with increasing temperature, extremely over 60 degrees C. The enzyme did not require Ca2+ ions for activity, and was strongly inhibited by EDTA and Co2+. PL was active on polygalacturonic acid and esterified pectin, but the affinity showed a maximum for intermediate esterified pectins and decreased over a value of 50% of esterification. The best substrate was 29.5% methylated pectin. PL cleaved polygalacturonic acid via a beta-elimination mechanism as shown by NMR analysis. PL released unsaturated tetragalacturonic acid from citrus pectin and polygalacturonic acid, but did not show any side activities on other hemicelluloses. On polygalacturonic acid PL showed a Km of 0.24 gl(-1) and a vmax of 0.72 gl(-1)min(-1). The applicability of pectate lyase for the bioscouring process was tested on a cotton fabric. Removal of up to 80% of pectin was proven by means of ruthenium red dyeing and HPAEC (65%). Structural contact angle measurements clearly indicated the increased hydrophilicity of enzyme treated fabrics.
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Affiliation(s)
- Barbara G Klug-Santner
- Department of Environmental Biotechnology, Graz University of Technology, Petersgasse 12, A-8010 Graz, Austria
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25
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Shallom D, Golan G, Shoham G, Shoham Y. Effect of dimer dissociation on activity and thermostability of the alpha-glucuronidase from Geobacillus stearothermophilus: dissecting the different oligomeric forms of family 67 glycoside hydrolases. J Bacteriol 2004; 186:6928-37. [PMID: 15466046 PMCID: PMC522207 DOI: 10.1128/jb.186.20.6928-6937.2004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The oligomeric organization of enzymes plays an important role in many biological processes, such as allosteric regulation, conformational stability and thermal stability. alpha-Glucuronidases are family 67 glycosidases that cleave the alpha-1,2-glycosidic bond between 4-O-methyl-D-glucuronic acid and xylose units as part of an array of hemicellulose-hydrolyzing enzymes. Currently, two crystal structures of alpha-glucuronidases are available, those from Geobacillus stearothermophilus (AguA) and from Cellvibrio japonicus (GlcA67A). Both enzymes are homodimeric, but surprisingly their dimeric organization is different, raising questions regarding the significance of dimerization for the enzymes' activity and stability. Structural comparison of the two enzymes suggests several elements that are responsible for the different dimerization organization. Phylogenetic analysis shows that the alpha-glucuronidases AguA and GlcA67A can be classified into two distinct subfamilies of bacterial alpha-glucuronidases, where the dimer-forming residues of each enzyme are conserved only within its own subfamily. It seems that the different dimeric forms of AguA and GlcA67A represent the two alternative dimeric organizations of these subfamilies. To study the biological significance of the dimerization in alpha-glucuronidases, we have constructed a monomeric form of AguA by mutating three of its interface residues (W328E, R329T, and R665N). The activity of the monomer was significantly lower than the activity of the wild-type dimeric AguA, and the optimal temperature for activity of the monomer was around 35 degrees C, compared to 65 degrees C of the wild-type enzyme. Nevertheless, the melting temperature of the monomeric protein, 72.9 degrees C, was almost identical to that of the wild-type, 73.4 degrees C. It appears that the dimerization of AguA is essential for efficient catalysis and that the dissociation into monomers results in subtle conformational changes in the structure which indirectly influence the active site region and reduce the activity. Structural and mechanistic explanations for these effects are discussed.
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Affiliation(s)
- Dalia Shallom
- Department of Biotechnology and Food Engineering, Technion-ITT, Haifa 32000, Israel
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26
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Golan G, Shallom D, Teplitsky A, Zaide G, Shulami S, Baasov T, Stojanoff V, Thompson A, Shoham Y, Shoham G. Crystal structures of Geobacillus stearothermophilus alpha-glucuronidase complexed with its substrate and products: mechanistic implications. J Biol Chem 2003; 279:3014-24. [PMID: 14573597 DOI: 10.1074/jbc.m310098200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alpha-glucuronidases cleave the alpha-1,2-glycosidic bond between 4-O-methyl-d-glucuronic acid and short xylooligomers as part of the hemicellulose degradation system. To date, all of the alpha-glucuronidases are classified as family 67 glycosidases, which catalyze the hydrolysis via the investing mechanism. Here we describe several high resolution crystal structures of the alpha-glucuronidase (AguA) from Geobacillus stearothermophilus, in complex with its substrate and products. In the complex of AguA with the intact substrate, the 4-O-methyl-d-glucuronic acid sugar ring is distorted into a half-chair conformation, which is closer to the planar conformation required for the oxocarbenium ion-like transition state structure. In the active site, a water molecule is coordinated between two carboxylic acids, in an appropriate position to act as a nucleophile. From the structural data it is likely that two carboxylic acids, Asp(364) and Glu(392), activate together the nucleophilic water molecule. The loop carrying the catalytic general acid Glu(285) cannot be resolved in some of the structures but could be visualized in its "open" and "closed" (catalytic) conformations in other structures. The protonated state of Glu(285) is presumably stabilized by its proximity to the negative charge of the substrate, representing a new variation of substrate-assisted catalysis mechanism.
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Affiliation(s)
- Gali Golan
- Department of Inorganic Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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27
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Nagy T, Nurizzo D, Davies GJ, Biely P, Lakey JH, Bolam DN, Gilbert HJ. The alpha-glucuronidase, GlcA67A, of Cellvibrio japonicus utilizes the carboxylate and methyl groups of aldobiouronic acid as important substrate recognition determinants. J Biol Chem 2003; 278:20286-92. [PMID: 12654910 DOI: 10.1074/jbc.m302205200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha-Glucuronidases are key components of the ensemble of enzymes that degrade the plant cell wall. They hydrolyze the alpha1,2-glycosidic bond between 4-O-methyl-d-glucuronic acid (4-O-MeGlcA) and the xylan or xylooligosaccharide backbone. Here we report the crystal structure of an inactive mutant (E292A) of the alpha-glucuronidase, GlcA67A, from Cellvibrio japonicus in complex with its substrate. The data show that the 4-O-methyl group of the substrate is accommodated within a hydrophobic sheath flanked by Val-210 and Trp-160, whereas the carboxylate moiety is located within a positively charged region of the substrate-binding pocket. The carboxylate side chains of Glu-393 and Asp-365, on the "beta-face" of 4-O-MeGlcA, form hydrogen bonds with a water molecule that is perfectly positioned to mount a nucleophilic attack at the anomeric carbon of the target glycosidic bond, providing further support for the view that, singly or together, these amino acids function as the catalytic base. The capacity of reaction products and product analogues to inhibit GlcA67A shows that the 4-O-methyl group, the carboxylate, and the xylose sugar of aldobiouronic acid all play an important role in substrate binding. Site-directed mutagenesis informed by the crystal structure of enzyme-ligand complexes was used to probe the importance of highly conserved residues at the active site of GlcA67A. The biochemical properties of K288A, R325A, and K360A show that a constellation of three basic amino acids (Lys-288, Arg-325, and Lys-360) plays a critical role in binding the carboxylate moiety of 4-O-MeGlcA. Disruption of the apolar nature of the pocket created by Val-210 (V210N and V210S) has a detrimental effect on substrate binding, although the reduction in affinity is not reflected by an inability to accommodate the 4-O-methyl group. Replacing the two tryptophan residues that stack against the sugar rings of the substrate with alanine (W160A and W543A) greatly reduced activity.
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Affiliation(s)
- Tibor Nagy
- School of Cell and Molecular Biosciences, The University of Newcastle upon Tyne, United Kingdom
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28
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Nagy T, Emami K, Fontes CMGA, Ferreira LMA, Humphry DR, Gilbert HJ. The membrane-bound alpha-glucuronidase from Pseudomonas cellulosa hydrolyzes 4-O-methyl-D-glucuronoxylooligosaccharides but not 4-O-methyl-D-glucuronoxylan. J Bacteriol 2002; 184:4925-9. [PMID: 12169619 PMCID: PMC135289 DOI: 10.1128/jb.184.17.4925-4929.2002] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The microbial degradation of xylan is a key biological process. Hardwood 4-O-methyl-D-glucuronoxylans are extensively decorated with 4-O-methyl-D-glucuronic acid, which is cleaved from the polysaccharides by alpha-glucuronidases. In this report we describe the primary structures of the alpha-glucuronidase from Cellvibrio mixtus (C. mixtus GlcA67A) and the alpha-glucuronidase from Pseudomonas cellulosa (P. cellulosa GlcA67A) and characterize P. cellulosa GlcA67A. The primary structures of C. mixtus GlcA67A and P. cellulosa GlcA67A, which are 76% identical, exhibit similarities with alpha-glucuronidases in glycoside hydrolase family 67. The membrane-associated pseudomonad alpha-glucuronidase released 4-O-methyl-D-glucuronic acid from 4-O-methyl-D-glucuronoxylooligosaccharides but not from 4-O-methyl-D-glucuronoxylan. We propose that the role of the glucuronidase, in combination with cell-associated xylanases, is to hydrolyze decorated xylooligosaccharides, generated by extracellular hemicellulases, to xylose and 4-O-methyl-D-glucuronic acid, enabling the pseudomonad to preferentially utilize the sugars derived from these polymers.
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Affiliation(s)
- Tibor Nagy
- Department of Biological and Nutritional Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, United Kingdom
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Nurizzo D, Nagy T, Gilbert HJ, Davies GJ. The structural basis for catalysis and specificity of the Pseudomonas cellulosa alpha-glucuronidase, GlcA67A. Structure 2002; 10:547-56. [PMID: 11937059 DOI: 10.1016/s0969-2126(02)00742-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Alpha-glucuronidases, components of an ensemble of enzymes central to the recycling of photosynthetic biomass, remove the alpha-1,2 linked 4-O-methyl glucuronic acid from xylans. The structure of the alpha-glucuronidase, GlcA67A, from Pseudomonas cellulosa reveals three domains, the central of which is a (beta/alpha)(8) barrel housing the catalytic apparatus. Complexes of the enzyme with the individual reaction products, either xylobiose or glucuronic acid, and the ternary complex of both glucuronic acid and xylotriose reveal a "blind" pocket which selects for short decorated xylooligosaccharides substituted with the uronic acid at their nonreducing end, consistent with kinetic data. The catalytic center reveals a constellation of carboxylates; Glu292 is poised to provide protonic assistance to leaving group departure with Glu393 and Asp365 both appropriately positioned to provide base-catalyzed assistance for inverting nucleophilic attack by water.
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Affiliation(s)
- Didier Nurizzo
- Structural Biology Laboratory, Department of Chemistry, The University of York, Heslington, United Kingdom
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de Vries RP, Visser J. Aspergillus enzymes involved in degradation of plant cell wall polysaccharides. Microbiol Mol Biol Rev 2001; 65:497-522, table of contents. [PMID: 11729262 PMCID: PMC99039 DOI: 10.1128/mmbr.65.4.497-522.2001] [Citation(s) in RCA: 542] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Degradation of plant cell wall polysaccharides is of major importance in the food and feed, beverage, textile, and paper and pulp industries, as well as in several other industrial production processes. Enzymatic degradation of these polymers has received attention for many years and is becoming a more and more attractive alternative to chemical and mechanical processes. Over the past 15 years, much progress has been made in elucidating the structural characteristics of these polysaccharides and in characterizing the enzymes involved in their degradation and the genes of biotechnologically relevant microorganisms encoding these enzymes. The members of the fungal genus Aspergillus are commonly used for the production of polysaccharide-degrading enzymes. This genus produces a wide spectrum of cell wall-degrading enzymes, allowing not only complete degradation of the polysaccharides but also tailored modifications by using specific enzymes purified from these fungi. This review summarizes our current knowledge of the cell wall polysaccharide-degrading enzymes from aspergilli and the genes by which they are encoded.
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Affiliation(s)
- R P de Vries
- Molecular Genetics of Industrial Microorganisms, Wageningen University, 6703 HA Wageningen, The Netherlands.
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Zaide G, Shallom D, Shulami S, Zolotnitsky G, Golan G, Baasov T, Shoham G, Shoham Y. Biochemical characterization and identification of catalytic residues in alpha-glucuronidase from Bacillus stearothermophilus T-6. ACTA ACUST UNITED AC 2001; 268:3006-16. [PMID: 11358519 DOI: 10.1046/j.1432-1327.2001.02193.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Alpha-D-glucuronidases cleave the alpha-1,2-glycosidic bond of the 4-O-methyl-D-glucuronic acid side chain of xylan, as a part of an array of xylan hydrolyzing enzymes. The alpha-D-glucuronidase from Bacillus stearothermophilus T-6 was overexpressed in Escherichia coli using the T7 polymerase expression system. The purification procedure included two steps, heat treatment and gel filtration chromatography, and provided over 0.3 g of pure enzyme from 1 L of overnight culture. Based on gel filtration, the native protein is comprised of two identical subunits. Kinetic constants with aldotetraouronic acid as a substrate, at 55 degrees C, were a Km of 0.2 mM, and a specific activity of 42 U x mg(-1) (kcat = 54.9 s(-1)). The enzyme was most active at 65 degrees C, pH 5.5-6.0, in a 10-min assay, and retained 100% of its activity following incubation at 70 degrees C for 20 min. Based on differential scanning calorimetry, the protein denatured at 73.4 degrees C. Truncated forms of the enzyme, lacking either 126 amino acids from its N-terminus or 81 amino acids from its C-terminus, exhibited low residual activity, indicating that the catalytic site is located in the central region of the protein. To identify the potential catalytic residues, site-directed mutagenesis was applied on highly conserved acidic amino acids in the central region. The replacements Glu392-->Cys and Asp364-->Ala resulted in a decrease in activity of about five orders of magnitude, suggesting that these residues are the catalytic pair.
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Affiliation(s)
- G Zaide
- Department of Food Engineering and Biotechnology, Technion - Israel Institute of Technology, Haifa, Israel
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