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Li J, Wiebenga A, Lipzen A, Ng V, Tejomurthula S, Zhang Y, Grigoriev IV, Peng M, de Vries RP. Comparative Genomics and Transcriptomics Analyses Reveal Divergent Plant Biomass-Degrading Strategies in Fungi. J Fungi (Basel) 2023; 9:860. [PMID: 37623631 PMCID: PMC10455118 DOI: 10.3390/jof9080860] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/15/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023] Open
Abstract
Plant biomass is one of the most abundant renewable carbon sources, which holds great potential for replacing current fossil-based production of fuels and chemicals. In nature, fungi can efficiently degrade plant polysaccharides by secreting a broad range of carbohydrate-active enzymes (CAZymes), such as cellulases, hemicellulases, and pectinases. Due to the crucial role of plant biomass-degrading (PBD) CAZymes in fungal growth and related biotechnology applications, investigation of their genomic diversity and transcriptional dynamics has attracted increasing attention. In this project, we systematically compared the genome content of PBD CAZymes in six taxonomically distant species, Aspergillus niger, Aspergillus nidulans, Penicillium subrubescens, Trichoderma reesei, Phanerochaete chrysosporium, and Dichomitus squalens, as well as their transcriptome profiles during growth on nine monosaccharides. Considerable genomic variation and remarkable transcriptomic diversity of CAZymes were identified, implying the preferred carbon source of these fungi and their different methods of transcription regulation. In addition, the specific carbon utilization ability inferred from genomics and transcriptomics was compared with fungal growth profiles on corresponding sugars, to improve our understanding of the conversion process. This study enhances our understanding of genomic and transcriptomic diversity of fungal plant polysaccharide-degrading enzymes and provides new insights into designing enzyme mixtures and metabolic engineering of fungi for related industrial applications.
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Affiliation(s)
- Jiajia Li
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands; (J.L.); (M.P.)
| | - Ad Wiebenga
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands; (J.L.); (M.P.)
| | - Anna Lipzen
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA; (A.L.); (V.N.); (S.T.); (Y.Z.); (I.V.G.)
| | - Vivian Ng
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA; (A.L.); (V.N.); (S.T.); (Y.Z.); (I.V.G.)
| | - Sravanthi Tejomurthula
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA; (A.L.); (V.N.); (S.T.); (Y.Z.); (I.V.G.)
| | - Yu Zhang
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA; (A.L.); (V.N.); (S.T.); (Y.Z.); (I.V.G.)
| | - Igor V. Grigoriev
- USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA; (A.L.); (V.N.); (S.T.); (Y.Z.); (I.V.G.)
- Plant and Microbial Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Mao Peng
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands; (J.L.); (M.P.)
| | - Ronald P. de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands; (J.L.); (M.P.)
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2
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Agger JW, Madsen MS, Martinsen LK, Martins PA, Barrett K, Meyer AS. New insights to diversity and enzyme-substrate interactions of fungal glucuronoyl esterases. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12575-4. [PMID: 37256329 DOI: 10.1007/s00253-023-12575-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 06/01/2023]
Abstract
Glucuronoyl esterases (GEs) (EC 3.1.1.117) catalyze the cleavage of ester-linked lignin-carbohydrate complexes that has high impact on the plant cell wall integrity. The GEs are among the very few known types of hydrolytic enzymes that act at the interface of lignin, or which may potentially interact with lignin itself. In this review, we provide the latest update of the current knowledge on GEs with a special focus on the fungal variants. In addition, we have established the phylogenetic relationship between all GEs and this reveals that the fungal enzymes largely fall into one major branch, together with only a minor subset of bacterial enzymes. About 22% of the fungal proteins carry an additional domain, which is almost exclusively a CBM1 binding domain. We address how GEs may interact with the lignin-side of their substrate by molecular docking experiments based on the known structure of the Cerrena unicolor GE (CuGE). The docking studies indicate that there are no direct interactions between the enzyme and the lignin polymer, that the lignin-moiety is facing away from the protein surface and that an elongated carbon-chain between the ester-linkage and the first phenyl of lignin is preferable. Much basic research on these enzymes has been done over the past 15 years, but the next big step forward for these enzymes is connected to application and how these enzymes can facilitate the use of lignocellulose as a renewable resource. KEY POINTS: Fungal GEs are closely related and are sometimes linked to a binding module Molecular docking suggests good accommodation of lignin-like substructures GEs could be among the first expressed enzymes during fungal growth on biomass.
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Affiliation(s)
- Jane Wittrup Agger
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 224, 2800, Kongens Lyngby, Denmark.
| | - Michael Schmidt Madsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 224, 2800, Kongens Lyngby, Denmark
| | - Line Korte Martinsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 224, 2800, Kongens Lyngby, Denmark
| | - Pedro Alves Martins
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 224, 2800, Kongens Lyngby, Denmark
| | - Kristian Barrett
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 224, 2800, Kongens Lyngby, Denmark
| | - Anne S Meyer
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 224, 2800, Kongens Lyngby, Denmark
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3
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Wang R, Arioka M. Glucuronoyl esterase facilitates biomass degradation in Neurospora crassa by upregulating the expression of plant biomass-degrading enzymes. J GEN APPL MICROBIOL 2023; 68:278-286. [PMID: 35858815 DOI: 10.2323/jgam.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Glucuronoyl esterase (GE) is a promising agent for the delignification of plant biomass since it has been shown to cleave the linkage between xylan and lignin in vitro. In this study, we demonstrate that NcGE, a GE from Neurospora crassa, stimulates plant biomass degradation. In vitro, NcGE synergistically increased the release of reducing sugars from plant biomass when added together with cellulase or xylanase. In vivo, overexpression of NcGE in N. crassa resulted in an increase in xylanolytic activity. Consistently, elevated transcription of genes encoding the major plant biomass degrading-enzymes (PBDEs) was observed in the NcGE overexpression strain. Increased xylanolytic activity and transcription of PDBE genes were largely abolished when the transcription factors clr-1, clr-2, or xlr-1 were deleted. Interestingly, the expression of some PBDE genes was increased when the hydrolysate of plant biomass by NcGE was added to the culture medium. We propose that NcGE boosts the production of PBDEs through the activation of key transcription factors, which is presumably caused by NcGE-mediated generation of hypothetical inducer(s) from plant biomass.
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Affiliation(s)
- Ruijie Wang
- Department of Biotechnology, The University of Tokyo
| | - Manabu Arioka
- Department of Biotechnology, The University of Tokyo.,Collaborative Research Institute for Innovative Microbiology (CRIIM), The University of Tokyo
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4
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Glucuronoyl esterases - enzymes to decouple lignin and carbohydrates and enable better utilization of renewable plant biomass. Essays Biochem 2023; 67:493-503. [PMID: 36651189 PMCID: PMC10154605 DOI: 10.1042/ebc20220155] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/09/2022] [Accepted: 01/04/2023] [Indexed: 01/19/2023]
Abstract
Glucuronoyl esterases (GEs) are microbial enzymes able to cleave covalent linkages between lignin and carbohydrates in the plant cell wall. GEs are serine hydrolases found in carbohydrate esterase family 15 (CE15), which belongs to the large α/β hydrolase superfamily. GEs have been shown to reduce plant cell wall recalcitrance by hydrolysing the ester bonds found between glucuronic acid moieties on xylan polysaccharides and lignin. In recent years, the exploration of CE15 has broadened significantly and focused more on bacterial enzymes, which are more diverse in terms of sequence and structure to their fungal counterparts. Similar to fungal GEs, the bacterial enzymes are able to improve overall biomass deconstruction but also appear to have less strict substrate preferences for the uronic acid moiety. The structures of bacterial GEs reveal that they often have large inserts close to the active site, with implications for more extensive substrate interactions than the fungal GEs which have more open active sites. In this review, we highlight the recent work on GEs which has predominantly regarded bacterial enzymes, and discuss similarities and differences between bacterial and fungal enzymes in terms of the biochemical properties, diversity in sequence and modularity, and structural variations that have been discovered thus far in CE15.
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5
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Microbial xylanolytic carbohydrate esterases. Essays Biochem 2022; 67:479-491. [PMID: 36468678 DOI: 10.1042/ebc20220129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/04/2022] [Accepted: 11/17/2022] [Indexed: 12/12/2022]
Abstract
Abstract
This article reviews microbial esterases participating in the degradation of the major plant hemicellulose, xylan. The main chain of this polysaccharide built of β-1,4-glycosidically linked xylopyranosyl residues is substituted by other sugars and also partially acetylated. Besides esters of acetic acid, there are two other types of ester linkages in plant xylans. L-Arabinofuranosyl side chains form esters with phenolic acids, predominantly with ferulic acid. The dimerization of ferulic acid residues leads to cross-links connecting the hemicellulose molecules. Ferulic acid cross-links were shown to serve as covalent linkage between lignin and hemicellulose. Another cross-linking between lignin and hemicellulose is provided by esters between the xylan side residues of glucuronic or 4-O-methyl-D-glucurononic acid and lignin alcohols. Regardless of the cross-linking, the side residues prevent xylan main chains from association that leads to crystallization similar to that of cellulose. Simultaneously, xylan decorations hamper the action of enzymes acting on the main chain. The enzymatic breakdown of plant xylan, therefore, requires a concerted action of glycanases attacking the main chain and enzymes catalyzing debranching, called accessory xylanolytic enzymes including xylanolytic esterases. While acetylxylan esterases and feruloyl esterases participate directly in xylan degradation, glucuronoyl esterases catalyze its separation from lignin. The current state of knowledge of diversity, classification and structure–function relationship of these three types of xylanolytic carbohydrate esterases is discussed with emphasis on important aspects of their future research relevant to their industrial applications.
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6
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Viegas MF, Neves RPP, Ramos MJ, Fernandes PA. QM/MM Study of the Reaction Mechanism of Thermophilic Glucuronoyl Esterase for Biomass Treatment. Chemphyschem 2022; 23:e202200269. [PMID: 35925549 DOI: 10.1002/cphc.202200269] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/23/2022] [Indexed: 11/06/2022]
Abstract
Hydrolysis of lignocellulosic biomass, composed of a lignin-carbohydrate-complex (LCC) matrix, is critical for producing bioethanol from glucose. However, current methods for LCC processing require costly and polluting processes. The fungal Thermothelomyces thermophila glucuronoyl esterase (TtGE) is a promising thermophilic enzyme that hydrolyses LCC ester bonds. This study describes the TtGE catalytic mechanism using QM/MM methods. Two nearly-degenerate rate-determining transition states were found, with barriers of 16 and 17 kcal ⋅ mol-1 , both with a zwitterionic nature that results from a proton interplay from His346 to either the Ser213-hydroxyl or the lignin leaving group and the rehybridisation of the ester moiety of the substrate to an alkoxide. An oxyanion hole, characteristic of esterases, was provided by the conserved Arg214 through its backbone and sidechain. Our work further suggests that a mutation of Glu267 to a non-negative residue will decrease the energetic barrier in ca. -5 kcal ⋅ mol-1 , improving the catalytic rate of TtGE.
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Affiliation(s)
- Matilde F Viegas
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal
| | - Rui P P Neves
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal
| | - Maria J Ramos
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal
| | - Pedro A Fernandes
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal
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7
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Hameleers L, Penttinen L, Ikonen M, Jaillot L, Fauré R, Terrapon N, Deuss PJ, Hakulinen N, Master ER, Jurak E. Polysaccharide utilization loci-driven enzyme discovery reveals BD-FAE: a bifunctional feruloyl and acetyl xylan esterase active on complex natural xylans. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:127. [PMID: 34059129 PMCID: PMC8165983 DOI: 10.1186/s13068-021-01976-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/19/2021] [Indexed: 05/10/2023]
Abstract
BACKGROUND Nowadays there is a strong trend towards a circular economy using lignocellulosic biowaste for the production of biofuels and other bio-based products. The use of enzymes at several stages of the production process (e.g., saccharification) can offer a sustainable route due to avoidance of harsh chemicals and high temperatures. For novel enzyme discovery, physically linked gene clusters targeting carbohydrate degradation in bacteria, polysaccharide utilization loci (PULs), are recognized 'treasure troves' in the era of exponentially growing numbers of sequenced genomes. RESULTS We determined the biochemical properties and structure of a protein of unknown function (PUF) encoded within PULs of metagenomes from beaver droppings and moose rumen enriched on poplar hydrolysate. The corresponding novel bifunctional carbohydrate esterase (CE), now named BD-FAE, displayed feruloyl esterase (FAE) and acetyl esterase activity on simple, synthetic substrates. Whereas acetyl xylan esterase (AcXE) activity was detected on acetylated glucuronoxylan from birchwood, only FAE activity was observed on acetylated and feruloylated xylooligosaccharides from corn fiber. The genomic contexts of 200 homologs of BD-FAE revealed that the 33 closest homologs appear in PULs likely involved in xylan breakdown, while the more distant homologs were found either in alginate-targeting PULs or else outside PUL contexts. Although the BD-FAE structure adopts a typical α/β-hydrolase fold with a catalytic triad (Ser-Asp-His), it is distinct from other biochemically characterized CEs. CONCLUSIONS The bifunctional CE, BD-FAE, represents a new candidate for biomass processing given its capacity to remove ferulic acid and acetic acid from natural corn and birchwood xylan substrates, respectively. Its detailed biochemical characterization and solved crystal structure add to the toolbox of enzymes for biomass valorization as well as structural information to inform the classification of new CEs.
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Affiliation(s)
- Lisanne Hameleers
- Department of Bioproduct Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Leena Penttinen
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland
| | - Martina Ikonen
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland
| | - Léa Jaillot
- Architecture Et Fonction Des Macromolécules Biologiques (AFMB), UMR7257 Centre National de La Recherche Scientifique (CNRS) and Aix-Marseille Université (AMU), USC1408 Institut National de Recherche Pour L'Agriculture, l'Alimentation Et L'Environnement (INRAE), 13288, Marseille cedex 9, France
| | - Régis Fauré
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Nicolas Terrapon
- Architecture Et Fonction Des Macromolécules Biologiques (AFMB), UMR7257 Centre National de La Recherche Scientifique (CNRS) and Aix-Marseille Université (AMU), USC1408 Institut National de Recherche Pour L'Agriculture, l'Alimentation Et L'Environnement (INRAE), 13288, Marseille cedex 9, France
| | - Peter J Deuss
- Department of Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Nina Hakulinen
- Department of Chemistry, University of Eastern Finland, Yliopistokatu 7, 80130, Joensuu, Finland
| | - Emma R Master
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Edita Jurak
- Department of Bioproduct Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
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8
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Ernst HA, Mosbech C, Langkilde AE, Westh P, Meyer AS, Agger JW, Larsen S. The structural basis of fungal glucuronoyl esterase activity on natural substrates. Nat Commun 2020; 11:1026. [PMID: 32094331 PMCID: PMC7039992 DOI: 10.1038/s41467-020-14833-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 02/06/2020] [Indexed: 01/06/2023] Open
Abstract
Structural and functional studies were conducted of the glucuronoyl esterase (GE) from Cerrena unicolor (CuGE), an enzyme catalyzing cleavage of lignin-carbohydrate ester bonds. CuGE is an α/β-hydrolase belonging to carbohydrate esterase family 15 (CE15). The enzyme is modular, comprised of a catalytic and a carbohydrate-binding domain. SAXS data show CuGE as an elongated rigid molecule where the two domains are connected by a rigid linker. Detailed structural information of the catalytic domain in its apo- and inactivated form and complexes with aldouronic acids reveal well-defined binding of the 4-O-methyl-a-D-glucuronoyl moiety, not influenced by the nature of the attached xylo-oligosaccharide. Structural and sequence comparisons within CE15 enzymes reveal two distinct structural subgroups. CuGE belongs to the group of fungal CE15-B enzymes with an open and flat substrate-binding site. The interactions between CuGE and its natural substrates are explained and rationalized by the structural results, microscale thermophoresis and isothermal calorimetry.
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Affiliation(s)
- Heidi A Ernst
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
| | - Caroline Mosbech
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800, Kongens Lyngby, Denmark
| | - Annette E Langkilde
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800, Kongens Lyngby, Denmark
| | - Anne S Meyer
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800, Kongens Lyngby, Denmark
| | - Jane W Agger
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800, Kongens Lyngby, Denmark.
| | - Sine Larsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark.
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9
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Mosbech C, Holck J, Meyer A, Agger JW. Enzyme kinetics of fungal glucuronoyl esterases on natural lignin-carbohydrate complexes. Appl Microbiol Biotechnol 2019; 103:4065-4075. [PMID: 30949809 DOI: 10.1007/s00253-019-09797-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/22/2019] [Accepted: 03/23/2019] [Indexed: 12/01/2022]
Abstract
Glucuronoyl esterases (CE15 family) enable targeted cleavage of ester linkages in lignin-carbohydrate complexes (LCCs), particularly those linking lignin and glucuronoyl residues in xylan. A substantial challenge in characterization and kinetic analysis of CE15 enzymes has been the lack of proper substrates. Here, we present an assay using an insoluble LCC-rich lignin fraction from birch; lignin-rich pellet (LRP). The assay employs quantification of enzyme reaction products by LC-MS. The kinetics of four fungal CE15 enzymes, PsGE, CuGE, TtGE, and AfuGE originating from lignocellulose-degrading fungi Punctularia strigosozonata, Cerrena unicolor, Thielavia terrestris, and Armillaria fuscipes respectively were characterized and compared using this new assay. All four enzymes had activity on LRP and showed a clear preference for the insoluble substrate compared with smaller soluble LCC mimicking esters. End-product profiles were near identical for the four enzymes but differences in kinetic parameters were observed. TtGE possesses an alternative active site compared with the three other enzymes as it has the position of the catalytic glutamic acid occupied by a serine. TtGE performed poorly compared with the other enzymes. We speculate that glucuronoyl LCCs are not the preferred substrate of TtGE. Removal of an N-terminal CBM on CuGE affected the catalytic efficiently of the enzyme by reducing Kcat by more than 30%. Reaction products were detected from all four CE15s on a similar substrate from spruce indicating a more generic GE activity not limited to the hardwood. The assay with natural substrate represents a novel tool to study the natural function and kinetics of CE15s.
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Affiliation(s)
- Caroline Mosbech
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, DK-2800, Kongens Lyngby, Denmark
| | - Jesper Holck
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, DK-2800, Kongens Lyngby, Denmark
| | - Anne Meyer
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, DK-2800, Kongens Lyngby, Denmark
| | - Jane Wittrup Agger
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, DK-2800, Kongens Lyngby, Denmark.
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10
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Tang J, Long L, Cao Y, Ding S. Expression and characterization of two glucuronoyl esterases from Thielavia terrestris and their application in enzymatic hydrolysis of corn bran. Appl Microbiol Biotechnol 2019; 103:3037-3048. [DOI: 10.1007/s00253-019-09662-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 01/08/2019] [Accepted: 01/22/2019] [Indexed: 01/13/2023]
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11
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Lin MI, Hiyama A, Kondo K, Nagata T, Katahira M. Classification of fungal glucuronoyl esterases (FGEs) and characterization of two new FGEs from Ceriporiopsis subvermispora and Pleurotus eryngii. Appl Microbiol Biotechnol 2018; 102:9635-9645. [PMID: 30232535 DOI: 10.1007/s00253-018-9318-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/21/2018] [Accepted: 08/08/2018] [Indexed: 11/29/2022]
Abstract
Fungal glucuronoyl esterases (FGEs) catalyze cleavage of the ester bond connecting a lignin alcohol to the xylan-bound 4-O-methyl-D-glucuronic acid of glucuronoxylans. Thus, FGEs are capable of degrading lignin-carbohydrate complexes and have potential for biotechnological applications toward woody biomass utilization. Therefore, identification and characterization of new FGEs are of critical importance. Firstly, in this study, we built a phylogenetic tree from almost 400 putative FGEs obtained on BLAST analysis and defined six main clades. In the phylogenetic tree, all the putative FGEs of ascomycetes cluster in clades I to IV, and most of the putative FGEs of basidiomycetes (B-FGEs) cluster in clades V to VI. Interestingly, several B-FGEs were found to cluster in clade II; most FGEs of clade II were found to have higher theoretical isoelectric points than those in the other five clades. To gain an insight into the putative FGEs in the clades that have not been characterized yet, we chose the FGEs of Ceriporiopsis subvermispora (CsGE) and Pleurotus eryngii (PeGE), which belong to clades V and II, respectively. The catalytic domains of both CsGE and PeGE were successfully expressed using Pichia pastoris, and then purified. Benzyl glucuronic acid was used as a substrate to confirm the activities of the CsGE and PeGE, and the hydrolyzed product, glucuronic acid, was quantified spectrophotometrically. Both CsGE and PeGE clearly exhibited the esterase activity. Additionally, we demonstrated that PeGE exhibits high tolerance toward several denaturing agents, which may make it a potentially more applicable enzyme.
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Affiliation(s)
- Meng-I Lin
- Institute of Advanced Energy, Kyoto University, Kyoto, 611-0011, Japan.,Graduate School of Energy Science, Kyoto University, Kyoto, 611-0011, Japan
| | - Akiho Hiyama
- Graduate School of Energy Science, Kyoto University, Kyoto, 611-0011, Japan
| | - Keiko Kondo
- Institute of Advanced Energy, Kyoto University, Kyoto, 611-0011, Japan
| | - Takashi Nagata
- Institute of Advanced Energy, Kyoto University, Kyoto, 611-0011, Japan. .,Graduate School of Energy Science, Kyoto University, Kyoto, 611-0011, Japan.
| | - Masato Katahira
- Institute of Advanced Energy, Kyoto University, Kyoto, 611-0011, Japan. .,Graduate School of Energy Science, Kyoto University, Kyoto, 611-0011, Japan.
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12
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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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13
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Huynh HH, Ishii N, Matsuo I, Arioka M. A novel glucuronoyl esterase from Aspergillus fumigatus-the role of conserved Lys residue in the preference for 4-O-methyl glucuronoyl esters. Appl Microbiol Biotechnol 2018; 102:2191-2201. [PMID: 29332217 DOI: 10.1007/s00253-018-8739-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/30/2017] [Accepted: 12/12/2017] [Indexed: 11/26/2022]
Abstract
Cellulose in plant cell walls is mainly covered by hemicellulose and lignin, and thus efficient removal of these components is thought to be a key step in the optimal utilization of lignocellulose. The recently discovered carbohydrate esterase (CE) 15 family of glucuronoyl esterases (GEs) which cleave the linkages between the free carboxyl group of D-glucuronic acid in hemicellulose and the benzyl groups in lignin residues could contribute to this process. Herein, we report the identification, functional expression, and enzymatic characterization of a GE, AfGE, from the filamentous fungus Aspergillus fumigatus. AfGE was heterologously expressed in Aspergillus oryzae, and the purified enzyme displayed the ability to degrade the synthetic substrates mimicking the ester linkage between hemicellulose and lignin. AfGE is a potentially industrially applicable enzyme due to its characteristic as a thermophilic enzyme with the favorable temperature of 40-50 °C at pH 5. Molecular modeling and site-directed mutagenesis studies of AfGE demonstrated that Lys209 plays an important role in the preference for the substrates containing 4-O-methyl group in the glucopyranose ring.
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Affiliation(s)
- Hung Hiep Huynh
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Nozomi Ishii
- Department of Chemistry and Chemical Biology, Gunma University, Maebashi, Japan
| | - Ichiro Matsuo
- Department of Chemistry and Chemical Biology, Gunma University, Maebashi, Japan
| | - Manabu Arioka
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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14
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Mosbech C, Holck J, Meyer AS, Agger JW. The natural catalytic function of CuGE glucuronoyl esterase in hydrolysis of genuine lignin-carbohydrate complexes from birch. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:71. [PMID: 29560026 PMCID: PMC5858132 DOI: 10.1186/s13068-018-1075-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/09/2018] [Indexed: 05/08/2023]
Abstract
BACKGROUND Glucuronoyl esterases belong to carbohydrate esterase family 15 and catalyze de-esterification. Their natural function is presumed to be cleavage of ester linkages in lignin-carbohydrate complexes particularly those linking lignin and glucuronoyl residues in xylans in hardwood. RESULTS Here, we show for the first time a detailed product profile of aldouronic acids released from birchwood lignin by a glucuronoyl esterase from the white-rot fungus Cerrena unicolor (CuGE). CuGE releases substrate for GH10 endo-xylanase which results in significantly increased product release compared to the action of endo-xylanase alone. CuGE also releases neutral xylo-oligosaccharides that can be ascribed to the enzymes feruloyl esterase side activity as demonstrated by release of ferulic acid from insoluble wheat arabinoxylan. CONCLUSION The data verify the enzyme's unique ability to catalyze removal of all glucuronoxylan associated with lignin and we propose that this is a direct result of enzymatic cleavage of the ester bonds connecting glucuronoxylan to lignin via 4-O-methyl glucuronoyl-ester linkages. This function appears important for the fungal organism's ability to effectively utilize all available carbohydrates in lignocellulosic substrates. In bioprocess perspectives, this enzyme is a clear candidate for polishing lignin for residual carbohydrates to achieve pure, native lignin fractions after minimal pretreatment.
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Affiliation(s)
- Caroline Mosbech
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads 229, 2800 Kgs. Lyngby, Denmark
| | - Jesper Holck
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads 229, 2800 Kgs. Lyngby, Denmark
| | - Anne S. Meyer
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads 229, 2800 Kgs. Lyngby, Denmark
| | - Jane Wittrup Agger
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads 229, 2800 Kgs. Lyngby, Denmark
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15
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Arnling Bååth J, Mazurkewich S, Knudsen RM, Poulsen JCN, Olsson L, Lo Leggio L, Larsbrink J. Biochemical and structural features of diverse bacterial glucuronoyl esterases facilitating recalcitrant biomass conversion. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:213. [PMID: 30083226 PMCID: PMC6069808 DOI: 10.1186/s13068-018-1213-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/23/2018] [Indexed: 05/02/2023]
Abstract
BACKGROUND Lignocellulose is highly recalcitrant to enzymatic deconstruction, where the recalcitrance primarily results from chemical linkages between lignin and carbohydrates. Glucuronoyl esterases (GEs) from carbohydrate esterase family 15 (CE15) have been suggested to play key roles in reducing lignocellulose recalcitrance by cleaving covalent ester bonds found between lignin and glucuronoxylan. However, only a limited number of GEs have been biochemically characterized and structurally determined to date, limiting our understanding of these enzymes and their potential exploration. RESULTS Ten CE15 enzymes from three bacterial species, sharing as little as 20% sequence identity, were characterized on a range of model substrates; two protein structures were solved, and insights into their regulation and biological roles were gained through gene expression analysis and enzymatic assays on complex biomass. Several enzymes with higher catalytic efficiencies on a wider range of model substrates than previously characterized fungal GEs were identified. Similarities and differences regarding substrate specificity between the investigated GEs were observed and putatively linked to their positioning in the CE15 phylogenetic tree. The bacterial GEs were able to utilize substrates lacking 4-OH methyl substitutions, known to be important for fungal enzymes. In addition, certain bacterial GEs were able to efficiently cleave esters of galacturonate, a functionality not previously described within the family. The two solved structures revealed similar overall folds to known structures, but also indicated active site regions allowing for more promiscuous substrate specificities. The gene expression analysis demonstrated that bacterial GE-encoding genes were differentially expressed as response to different carbon sources. Further, improved enzymatic saccharification of milled corn cob by a commercial lignocellulolytic enzyme cocktail when supplemented with GEs showcased their synergistic potential with other enzyme types on native biomass. CONCLUSIONS Bacterial GEs exhibit much larger diversity than fungal counterparts. In this study, we significantly expanded the existing knowledge on CE15 with the in-depth characterization of ten bacterial GEs broadly spanning the phylogenetic tree, and also presented two novel enzyme structures. Variations in transcriptional responses of CE15-encoding genes under different growth conditions suggest nonredundant functions for enzymes found in species with multiple CE15 genes and further illuminate the importance of GEs in native lignin-carbohydrate disassembly.
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Affiliation(s)
- Jenny Arnling Bååth
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Scott Mazurkewich
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | | | | | - Lisbeth Olsson
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Leila Lo Leggio
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Johan Larsbrink
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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Dilokpimol A, Mäkelä MR, Cerullo G, Zhou M, Varriale S, Gidijala L, Brás JL, Jütten P, Piechot A, Verhaert R, Faraco V, Hilden KS, de Vries RP. Fungal glucuronoyl esterases: Genome mining based enzyme discovery and biochemical characterization. N Biotechnol 2018; 40:282-287. [DOI: 10.1016/j.nbt.2017.10.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/24/2017] [Accepted: 10/11/2017] [Indexed: 10/18/2022]
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17
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Wong MT, Wang W, Couturier M, Razeq FM, Lombard V, Lapebie P, Edwards EA, Terrapon N, Henrissat B, Master ER. Comparative Metagenomics of Cellulose- and Poplar Hydrolysate-Degrading Microcosms from Gut Microflora of the Canadian Beaver ( Castor canadensis) and North American Moose ( Alces americanus) after Long-Term Enrichment. Front Microbiol 2017; 8:2504. [PMID: 29326667 PMCID: PMC5742341 DOI: 10.3389/fmicb.2017.02504] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/01/2017] [Indexed: 11/13/2022] Open
Abstract
To identify carbohydrate-active enzymes (CAZymes) that might be particularly relevant for wood fiber processing, we performed a comparative metagenomic analysis of digestive systems from Canadian beaver (Castor canadensis) and North American moose (Alces americanus) following 3 years of enrichment on either microcrystalline cellulose or poplar hydrolysate. In total, 9,386 genes encoding CAZymes and carbohydrate-binding modules (CBMs) were identified, with up to half predicted to originate from Firmicutes, Bacteroidetes, Chloroflexi, and Proteobacteria phyla, and up to 17% from unknown phyla. Both PCA and hierarchical cluster analysis distinguished the annotated glycoside hydrolase (GH) distributions identified herein, from those previously reported for grass-feeding mammals and herbivorous foragers. The CAZyme profile of moose rumen enrichments also differed from a recently reported moose rumen metagenome, most notably by the absence of GH13-appended dockerins. Consistent with substrate-driven convergence, CAZyme profiles from both poplar hydrolysate-fed cultures differed from cellulose-fed cultures, most notably by increased numbers of unique sequences belonging to families GH3, GH5, GH43, GH53, and CE1. Moreover, pairwise comparisons of moose rumen enrichments further revealed higher counts of GH127 and CE15 families in cultures fed with poplar hydrolysate. To expand our scope to lesser known carbohydrate-active proteins, we identified and compared multi-domain proteins comprising both a CBM and domain of unknown function (DUF) as well as proteins with unknown function within the 416 predicted polysaccharide utilization loci (PULs). Interestingly, DUF362, identified in iron-sulfur proteins, was consistently appended to CBM9; on the other hand, proteins with unknown function from PULs shared little identity unless from identical PULs. Overall, this study sheds new light on the lignocellulose degrading capabilities of microbes originating from digestive systems of mammals known for fiber-rich diets, and highlights the value of enrichment to select new CAZymes from metagenome sequences for future biochemical characterization.
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Affiliation(s)
- Mabel T Wong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Weijun Wang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Marie Couturier
- Centre de Recherches sur les Macromolécules Végétales - Université Grenoble Alpes, Grenoble, France.,Centre National de la Recherche Scientifique, Centre de Recherches sur les Macromolécules Végétales, Grenoble, France
| | - Fakhria M Razeq
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Vincent Lombard
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Marseille, France.,UMR 7257, Centre National de la Recherche Scientifique, Marseille, France
| | - Pascal Lapebie
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Marseille, France
| | - Elizabeth A Edwards
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Nicolas Terrapon
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Marseille, France
| | - Bernard Henrissat
- UMR 7257, Centre National de la Recherche Scientifique, Marseille, France.,Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada.,Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland
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18
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De Santi C, Gani OA, Helland R, Williamson A. Structural insight into a CE15 esterase from the marine bacterial metagenome. Sci Rep 2017; 7:17278. [PMID: 29222424 PMCID: PMC5722869 DOI: 10.1038/s41598-017-17677-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/28/2017] [Indexed: 12/02/2022] Open
Abstract
The family 15 carbohydrate esterase (CE15) MZ0003, which derives from a marine Arctic metagenome, has a broader substrate scope than other members of this family. Here we report the crystal structure of MZ0003, which reveals that residues comprising the catalytic triad differ from previously-characterized fungal homologs, and resolves three large loop regions that are unique to this bacterial sub-clade. The catalytic triad of the bacterial CE15, which includes Asp 332 as its third member, closely resembles that of family 1 carbohydrate esterases (CE1), despite the overall lower structural similarity with members of this family. Two of the three loop regions form a subdomain that deepens the active site pocket and includes several basic residues that contribute to the high positive charge surrounding the active site. Docking simulations predict specific interactions with the sugar moiety of glucuronic-acid substrates, and with aromatically-substituted derivatives that serve as model compounds for the lignin-carbohydrate complex of plant cell walls. Molecular dynamics simulations indicate considerable flexibility of the sub-domain in the substrate-bound form, suggesting plasticity to accommodate different substrates is possible. The findings from this first reported structure of a bacterial member of the CE15 family provide insight into the basis of its broader substrate specificity.
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Affiliation(s)
- Concetta De Santi
- Department of Chemistry, UiT The Arctic University of Norway, Tromsø, N-9037, Norway
| | - Osman Absm Gani
- Department of Chemistry, UiT The Arctic University of Norway, Tromsø, N-9037, Norway
| | - Ronny Helland
- NorStruct, Department of Chemistry, UiT The Arctic University of Norway, Tromsø, N-9037, Norway
| | - Adele Williamson
- Department of Chemistry, UiT The Arctic University of Norway, Tromsø, N-9037, Norway.
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