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Brunecky R, Knott BC, Subramanian V, Linger JG, Beckham GT, Amore A, Taylor LE, Vander Wall TA, Lunin VV, Zheng F, Garrido M, Schuster L, Fulk EM, Farmer S, Himmel ME, Decker SR. Engineering of glycoside hydrolase family 7 cellobiohydrolases directed by natural diversity screening. J Biol Chem 2024; 300:105749. [PMID: 38354778 PMCID: PMC10943489 DOI: 10.1016/j.jbc.2024.105749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 02/16/2024] Open
Abstract
Protein engineering and screening of processive fungal cellobiohydrolases (CBHs) remain challenging due to limited expression hosts, synergy-dependency, and recalcitrant substrates. In particular, glycoside hydrolase family 7 (GH7) CBHs are critically important for the bioeconomy and typically difficult to engineer. Here, we target the discovery of highly active natural GH7 CBHs and engineering of variants with improved activity. Using experimentally assayed activities of genome mined CBHs, we applied sequence and structural alignments to top performers to identify key point mutations linked to improved activity. From ∼1500 known GH7 sequences, an evolutionarily diverse subset of 57 GH7 CBH genes was expressed in Trichoderma reesei and screened using a multiplexed activity screening assay. Ten catalytically enhanced natural variants were identified, produced, purified, and tested for efficacy using industrially relevant conditions and substrates. Three key amino acids in CBHs with performance comparable or superior to Penicillium funiculosum Cel7A were identified and combinatorially engineered into P. funiculosum cel7a, expressed in T. reesei, and assayed on lignocellulosic biomass. The top performer generated using this combined approach of natural diversity genome mining, experimental assays, and computational modeling produced a 41% increase in conversion extent over native P. funiculosum Cel7A, a 55% increase over the current industrial standard T. reesei Cel7A, and 10% improvement over Aspergillus oryzae Cel7C, the best natural GH7 CBH previously identified in our laboratory.
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Affiliation(s)
- Roman Brunecky
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Brandon C Knott
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Venkataramanan Subramanian
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Jeffrey G Linger
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Gregg T Beckham
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Antonella Amore
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Larry E Taylor
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Todd A Vander Wall
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Vladimir V Lunin
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Fei Zheng
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Mercedes Garrido
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Logan Schuster
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Emily M Fulk
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Samuel Farmer
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Michael E Himmel
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA.
| | - Stephen R Decker
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA.
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Forsberg Z, Stepnov AA, Tesei G, Wang Y, Buchinger E, Kristiansen SK, Aachmann FL, Arleth L, Eijsink VGH, Lindorff-Larsen K, Courtade G. The effect of linker conformation on performance and stability of a two-domain lytic polysaccharide monooxygenase. J Biol Chem 2023; 299:105262. [PMID: 37734553 PMCID: PMC10598543 DOI: 10.1016/j.jbc.2023.105262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/05/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023] Open
Abstract
A considerable number of lytic polysaccharide monooxygenases (LPMOs) and other carbohydrate-active enzymes are modular, with catalytic domains being tethered to additional domains, such as carbohydrate-binding modules, by flexible linkers. While such linkers may affect the structure, function, and stability of the enzyme, their roles remain largely enigmatic, as do the reasons for natural variation in length and sequence. Here, we have explored linker functionality using the two-domain cellulose-active ScLPMO10C from Streptomyces coelicolor as a model system. In addition to investigating the WT enzyme, we engineered three linker variants to address the impact of both length and sequence and characterized these using small-angle X-ray scattering, NMR, molecular dynamics simulations, and functional assays. The resulting data revealed that, in the case of ScLPMO10C, linker length is the main determinant of linker conformation and enzyme performance. Both the WT and a serine-rich variant, which have the same linker length, demonstrated better performance compared with those with either a shorter linker or a longer linker. A highlight of our findings was the substantial thermostability observed in the serine-rich variant. Importantly, the linker affects thermal unfolding behavior and enzyme stability. In particular, unfolding studies show that the two domains unfold independently when mixed, whereas the full-length enzyme shows one cooperative unfolding transition, meaning that the impact of linkers in biomass-processing enzymes is more complex than mere structural tethering.
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Affiliation(s)
- Zarah Forsberg
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
| | - Anton A Stepnov
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Giulio Tesei
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Yong Wang
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark; College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Edith Buchinger
- Vectron Biosolutions AS, Trondheim, Norway; Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Sandra K Kristiansen
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Finn L Aachmann
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Lise Arleth
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Gaston Courtade
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway.
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Sidar A, Voshol GP, Vijgenboom E, Punt PJ. Novel Design of an α-Amylase with an N-Terminal CBM20 in Aspergillus niger Improves Binding and Processing of a Broad Range of Starches. Molecules 2023; 28:5033. [PMID: 37446690 DOI: 10.3390/molecules28135033] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/17/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023] Open
Abstract
In the starch processing industry including the food and pharmaceutical industries, α-amylase is an important enzyme that hydrolyses the α-1,4 glycosidic bonds in starch, producing shorter maltooligosaccharides. In plants, starch molecules are organised in granules that are very compact and rigid. The level of starch granule rigidity affects resistance towards enzymatic hydrolysis, resulting in inefficient starch degradation by industrially available α-amylases. In an approach to enhance starch hydrolysis, the domain architecture of a Glycoside Hydrolase (GH) family 13 α-amylase from Aspergillus niger was engineered. In all fungal GH13 α-amylases that carry a carbohydrate binding domain (CBM), these modules are of the CBM20 family and are located at the C-terminus of the α-amylase domain. To explore the role of the domain order, a new GH13 gene encoding an N-terminal CBM20 domain was designed and found to be fully functional. The starch binding capacity and enzymatic activity of N-terminal CBM20 α-amylase was found to be superior to that of native GH13 without CBM20. Based on the kinetic parameters, the engineered N-terminal CBM20 variant displayed surpassing activity rates compared to the C-terminal CBM20 version for the degradation on a wide range of starches, including the more resistant raw potato starch for which it exhibits a two-fold higher Vmax underscoring the potential of domain engineering for these carbohydrate active enzymes.
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Affiliation(s)
- Andika Sidar
- Institute of Biology Leiden, Leiden University, 2333 BE Leiden, The Netherlands
- Department of Food and Agricultural Product Technology, Gadjah Mada University, Yogyakarta 55281, Indonesia
| | - Gerben P Voshol
- Institute of Biology Leiden, Leiden University, 2333 BE Leiden, The Netherlands
- GenomeScan, 2333 BZ Leiden, The Netherlands
| | - Erik Vijgenboom
- Institute of Biology Leiden, Leiden University, 2333 BE Leiden, The Netherlands
| | - Peter J Punt
- Institute of Biology Leiden, Leiden University, 2333 BE Leiden, The Netherlands
- Ginkgo Bioworks, 3704 HE Zeist, The Netherlands
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4
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Kuch NJ, Kutschke ME, Parker A, Bingman CA, Fox BG. Contribution of calcium ligands in substrate binding and product release in the Acetovibrio thermocellus glycoside hydrolase family 9 cellulase CelR. J Biol Chem 2023; 299:104655. [PMID: 36990218 PMCID: PMC10149213 DOI: 10.1016/j.jbc.2023.104655] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
Enzymatic deconstruction of lignocellulosic biomass is crucial to establishment of the renewable biofuel and bioproduct economy. Better understanding of these enzymes, including their catalytic and binding domains, and other features offer potential avenues for improvement. Glycoside hydrolase family 9 (GH9) enzymes are attractive targets because they have members that exhibit exo- and endo-cellulolytic activity, processivity of reaction, and thermostability. This study examines a GH9 from Acetovibrio thermocellus ATCC 27405, AtCelR containing a catalytic domain and a carbohydrate binding module (CBM3c). Crystal structures of the enzyme without substrate, bound to cellohexaose (substrate) or cellobiose (product), show the positioning of ligands to calcium and adjacent residues in the catalytic domain that may contribute to substrate binding and facilitate product release. We also investigated the properties of the enzyme engineered to contain an additional carbohydrate binding module (CBM3a). Relative to the catalytic domain alone, CBM3a gave improved binding for Avicel (a crystalline form of cellulose), and catalytic efficiency (kcat/KM) was improved 40× with both CBM3c and CBM3a present. However, because of the molecular weight added by CBM3a, the specific activity of the engineered enzyme was not increased relative to the native construct consisting of only the catalytic and CBM3c domains. This work provides new insight into a potential role of the conserved calcium in the catalytic domain and identifies contributions and limitations of domain engineering for AtCelR and perhaps other GH9 enzymes.
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Affiliation(s)
- Nathaniel J Kuch
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Mark E Kutschke
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Alex Parker
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; Dane County Youth Apprenticeship Program, Dane County School Consortium, Monona, Wisconsin, USA
| | - Craig A Bingman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; Collaborative Crystallography Core, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Brian G Fox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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5
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Ahmad S, Sajjad M, Altayb HN, Sarim Imam S, Alshehri S, Ghoneim MM, Shahid S, Usman Mirza M, Shahid Nadeem M, Kazmi I, Waheed Akhtar M. Engineering processive cellulase of Clostridium thermocellum to divulge the role of the carbohydrate-binding module. Biotechnol Appl Biochem 2023; 70:290-305. [PMID: 35483889 DOI: 10.1002/bab.2352] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 04/05/2022] [Indexed: 11/11/2022]
Abstract
The processive cellulase (CelO) is an important modular enzyme of Clostridium thermocellum. To study the effect of the carbohydrate-binding module (CBM3b) on the catalytic domain of CelO (GH5), four engineered derivatives of CelO were designed by truncation and terminal fusion of CBM3b. These are CBM at the N-terminus, native form (CelO-BC, 62 kDa); catalytic domain only (CelO-C, 42 kDa); CBM at the C-terminus (CelO-CB, 54 kDa) and CBM attached at both termini (CelO-BCB, 73 kDa). All constructs were cloned into pET22b (+) and expressed in Escherichia coli BL21 (DE3) star. The expression levels of CelO-C, CelO-CB, CelO-BC, and CelO-BCB were 35%, 35%, 30%, and 20%, respectively. The enzyme activities of CelO-C, CelO-CB, CelO-BC, and CelO-BCB against 1% regenerated amorphous cellulose (RAC) were 860, 758, 985, and 1208 units per μmole of the enzyme, respectively. The enzymes were partially purified from the lysate of E. coli cells by heat treatment followed by anion exchange FPLC purification. Against RAC, CelO-C, CelO-CB, CelO-BC, and CelO-BCB showed KM values of 32, 33, 45, and 43 mg⋅mL-1 and Vmax values of 3571, 3846, 3571, and 4545 U⋅min-1 , respectively. CBM3b at the N-terminus of GH5 linked through a P/T-rich linker was found to enhance the catalytic activity and thermostability of the enzyme.
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Affiliation(s)
- Sajjad Ahmad
- School of Biological Science, University of the Punjab, Lahore, Pakistan
| | - Muhammad Sajjad
- School of Biological Science, University of the Punjab, Lahore, Pakistan
| | - Hisham N Altayb
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Syed Sarim Imam
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Sultan Alshehri
- Department of Pharmaceutical Sciences, College of Pharmacy, AlMaarefa University, Ad Diriyah, Saudi Arabia
| | - Mohammed M Ghoneim
- Department of Pharmaceutical Sciences, College of Pharmacy, AlMaarefa University, Ad Diriyah, Saudi Arabia
| | - Saher Shahid
- School of Biological Science, University of the Punjab, Lahore, Pakistan
| | - Muhammad Usman Mirza
- Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Laboratory of Medicinal Chemistry, University of Leuven, Leuven, Belgium
| | - Muhammad Shahid Nadeem
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Imran Kazmi
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
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6
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Chaudhari YB, Várnai A, Sørlie M, Horn SJ, Eijsink VGH. Engineering cellulases for conversion of lignocellulosic biomass. Protein Eng Des Sel 2023; 36:gzad002. [PMID: 36892404 PMCID: PMC10394125 DOI: 10.1093/protein/gzad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/13/2023] [Accepted: 02/24/2023] [Indexed: 03/10/2023] Open
Abstract
Lignocellulosic biomass is a renewable source of energy, chemicals and materials. Many applications of this resource require the depolymerization of one or more of its polymeric constituents. Efficient enzymatic depolymerization of cellulose to glucose by cellulases and accessory enzymes such as lytic polysaccharide monooxygenases is a prerequisite for economically viable exploitation of this biomass. Microbes produce a remarkably diverse range of cellulases, which consist of glycoside hydrolase (GH) catalytic domains and, although not in all cases, substrate-binding carbohydrate-binding modules (CBMs). As enzymes are a considerable cost factor, there is great interest in finding or engineering improved and robust cellulases, with higher activity and stability, easy expression, and minimal product inhibition. This review addresses relevant engineering targets for cellulases, discusses a few notable cellulase engineering studies of the past decades and provides an overview of recent work in the field.
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Affiliation(s)
- Yogesh B Chaudhari
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Svein J Horn
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
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7
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Guo W, Wang W, Tang J, Li T, Li X. Genome analysis and genomic comparison of a fungal cultivar of the nonsocial weevil Euops chinensis reveals its plant decomposition and protective roles in fungus-farming mutualism. Front Microbiol 2023; 14:1048910. [PMID: 36876094 PMCID: PMC9978505 DOI: 10.3389/fmicb.2023.1048910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/30/2023] [Indexed: 02/18/2023] Open
Abstract
Fungus-farming mutualisms are models for studying co-evolutionary among species. Compared to well-documented fungus-farming in social insects, the molecular aspects of fungus-farming mutualisms in nonsocial insects have been poorly explored. Euops chinensis is a solitary leaf-rolling weevil feeding on Japanese knotweed (Fallopia japonica). This pest has evolved a special proto-farming bipartite mutualism with the fungus Penicillium herquei, which provide nutrition and defensive protection for the E. chinensis larvae. Here, the genome of P. herquei was sequenced, and the structure and specific gene categories in the P. herquei genome were then comprehensively compared with the other two well-studied Penicillium species (P. decumbens and P. chrysogenum). The assembled P. herquei genome had a 40.25 Mb genome size with 46.7% GC content. A diverse set of genes associating with carbohydrate-active enzymes, cellulose and hemicellulose degradation, transporter, and terpenoid biosynthesis were detected in the P. herquei genome. Comparative genomics demonstrate that the three Penicillium species show similar metabolic and enzymatic potential, however, P. herquei has more genes associated with plant biomass degradation and defense but less genes associating with virulence pathogenicity. Our results provide molecular evidence for plant substrate breakdown and protective roles of P. herquei in E. chinensis mutualistic system. Large metabolic potential shared by Penicillium species at the genus level may explain why some Penicillium species are recruited by the Euops weevils as crop fungi.
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Affiliation(s)
- Wenfeng Guo
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China.,Guangxi Crop Genetic Improvement and Biotechnology Lab, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Wei Wang
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - Jun Tang
- Guangxi Crop Genetic Improvement and Biotechnology Lab, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Tianyu Li
- Wuhan Benagen Technology Company Limited, Wuhan, Hubei, China
| | - Xiaoqiong Li
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
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8
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Li P, Wang X, Zhang C, Xu D. Processive binding mechanism of Cel9G from Clostridium cellulovorans: molecular dynamics and free energy landscape investigations. Phys Chem Chem Phys 2023; 25:646-657. [DOI: 10.1039/d2cp04830b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The processive binding mechanism of cellulose by Cel9G from C. cellulovorans was investigated by MD and metadynamics simulations.
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Affiliation(s)
- Penghui Li
- College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Sichuan, Chengdu, 610064, P. R. China
| | - Xin Wang
- College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Sichuan, Chengdu, 610064, P. R. China
| | - Chunchun Zhang
- Analytical & Testing Center, Sichuan University, Sichuan, Chengdu, 610064, P. R. China
| | - Dingguo Xu
- College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Sichuan, Chengdu, 610064, P. R. China
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On the impact of carbohydrate-binding modules (CBMs) in lytic polysaccharide monooxygenases (LPMOs). Essays Biochem 2022; 67:561-574. [PMID: 36504118 PMCID: PMC10154629 DOI: 10.1042/ebc20220162] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 12/14/2022]
Abstract
Abstract
Lytic polysaccharide monooxygenases (LPMOs) have revolutionized our understanding of how enzymes degrade insoluble polysaccharides. Compared with the substantial knowledge developed on the structure and mode of action of the catalytic LPMO domains, the (multi)modularity of LPMOs has received less attention. The presence of other domains, in particular carbohydrate-binding modules (CBMs), tethered to LPMOs has profound implications for the catalytic performance of the full-length enzymes. In the last few years, studies on LPMO modularity have led to advancements in elucidating how CBMs, other domains, and linker regions influence LPMO structure and function. This mini review summarizes recent literature, with particular focus on comparative truncation studies, to provide an overview of the diversity in LPMO modularity and the functional implications of this diversity.
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10
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Li P, Shi M, Wang X, Xu D. QM/MM investigation of the catalytic mechanism of processive endoglucanase Cel9G from Clostridium cellulovorans. Phys Chem Chem Phys 2022; 24:11919-11930. [PMID: 35514276 DOI: 10.1039/d2cp00593j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Carbohydrate degradation catalyzed by glucoside hydrolases (GHs) is a major mechanism in biomass conversion. GH family 9 endoglucanase (Cel9G) from Clostridium cellulovorans, a typical multimodular enzyme, contains a catalytic domain closely linked to a family 3c carbohydrate-binding module (CBM3c). Unlike the conventional behavior proposed for other carbohydrate-binding modules, CBM3c has a direct impact on catalytic activity. In this work, extensive molecular dynamics (MD) simulations were employed to clarify the functional role of CBM3c. Furthermore, the detailed catalytic mechanism of Cel9G was investigated at the atomistic level using the combined quantum mechanical and molecular mechanical (QM/MM) method. Based on these simulations, owing to the rigidity of the peptide linker, CBM3c may affect the enzymatic activity via direct interactions with alpha helix 4 of GH9, especially with the K123 and H125 residues. In addition, using cellohexaose as a substrate, the QM/MM MD simulations confirmed that this enzyme can cleave the β-1,4-glycosidic linkage via an inverting mechanism. An oxocarbenium ion-like transition state was located with a barrier height of 19.6 kcal mol-1. Furthermore, the G(-1) pyranose unit preferentially adopted a distorted 1S5/4H5 conformer in the enzyme-substrate complex. For the cleavage of the glycosidic bond, we were able to identify a plausible route (1S5/4H5 → [4H5/4E]# → 4C1) from the reactant to the product at the G(-1) site.
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Affiliation(s)
- Penghui Li
- College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Chengdu, Sichuan, 610064, P. R. China.
| | - Mingsong Shi
- State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, P. R. China
| | - Xin Wang
- College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Chengdu, Sichuan, 610064, P. R. China.
| | - Dingguo Xu
- College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Chengdu, Sichuan, 610064, P. R. China.
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11
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Characterization of the chimeric protein cUBC1 engineered by substituting the linker of E2-25K into UBC1 enzyme of Saccharomyces cerevisiae. Int J Biol Macromol 2022; 209:991-1000. [PMID: 35429515 DOI: 10.1016/j.ijbiomac.2022.04.057] [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: 12/03/2021] [Revised: 03/27/2022] [Accepted: 04/07/2022] [Indexed: 11/21/2022]
Abstract
Ubiquitination is an important posttranslational modification of proteins in eukaryotic cells, wherein ubiquitin molecules are conjugated to target proteins. Ubiquitination is catalyzed by the cascade of ubiquitin activating enzyme (E1), ubiquitin conjugating enzyme (E2), and ubiquitin ligase (E3). The number of E2s encoded in eukaryotes partly explains their contribution to the inherent specificity of the ubiquitin system. The ubiquitin conjugating enzyme UBC1 of Saccharomyces cerevisiae participates the degradation of short-lived and abnormal proteins. UBC1 consists of two well-defined domains separated by a long flexible linker. E2-25K, the human homolog of UBC1 is crucial to neurons and its failure leads to neurodegenerative disorders. The linker of UBC1 is of 22 amino acids, while that of E2-25K has 6 amino acids. To understand the importance of the linker, the chimeric protein, cUBC1 was constructed by substituting the linker of E2-25K in UBC1. cUBC1 shows minor changes in its secondary structure. cUBC1 expression in ubc1 deletion mutants showed no effect over growth, thermotolerance and resistance to antibiotic stress. However, survival under heat stress was enhanced with cUBC1. Western blot analysis of the enzymatic activity showed cUBC1 performed equally well as UBC1. Hence, cUBC1 demonstrates that the shorter linker increased the stability of UBC1.
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12
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Yuan Y, Chen C, Wang X, Shen S, Guo X, Chen X, Yang F, Li X. A novel accessory protein ArCel5 from cellulose-gelatinizing fungus Arthrobotrys sp. CX1. BIORESOUR BIOPROCESS 2022; 9:27. [PMID: 38647580 PMCID: PMC10991334 DOI: 10.1186/s40643-022-00519-1] [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: 01/14/2022] [Accepted: 03/06/2022] [Indexed: 11/10/2022] Open
Abstract
Improved understanding of cellulose swelling mechanism is beneficial for increasing the hydrolysis efficiency of cellulosic substrates. Here, we report a family 5 glycoside hydrolase ArCel5 isolated from the cellulose-gelatinizing fungus Arthrobotrys sp. CX1. ArCel5 exhibited low specific hydrolysis activity and high cellulose swelling capability, which suggested that this protein might function as an accessory protein. Homology modeling glycosylation detection revealed that ArCel5 is a multi-domain protein including a family 1 carbohydrate-binding module, a glycosylation linker, and a catalytic domain. The adsorption capacity, structural changes and hydrature index of filter paper treated by different ArCel5 mutants demonstrated that CBM1 and linker played an essential role in recognizing, binding and decrystallizing cellulosic substrates, which further encouraged the synergistic action between ArCel5 and cellulases. Notably, glycosylation modification further strengthened the function of the linker region. Overall, our study provides insight into the cellulose decrystallization mechanism by a novel accessory protein ArCel5 that will benefit future applications.
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Affiliation(s)
- Yue Yuan
- School of Biological Engineering, Dalian Polytechnic University, Ganjingziqu, Dalian, 116034, People's Republic of China
| | - Chunshu Chen
- School of Biological Engineering, Dalian Polytechnic University, Ganjingziqu, Dalian, 116034, People's Republic of China
| | - Xueyan Wang
- School of Biological Engineering, Dalian Polytechnic University, Ganjingziqu, Dalian, 116034, People's Republic of China
| | - Shaonian Shen
- School of Biological Engineering, Dalian Polytechnic University, Ganjingziqu, Dalian, 116034, People's Republic of China
| | - Xiaoyu Guo
- School of Biological Engineering, Dalian Polytechnic University, Ganjingziqu, Dalian, 116034, People's Republic of China
| | - Xiaoyi Chen
- School of Biological Engineering, Dalian Polytechnic University, Ganjingziqu, Dalian, 116034, People's Republic of China
| | - Fan Yang
- School of Biological Engineering, Dalian Polytechnic University, Ganjingziqu, Dalian, 116034, People's Republic of China.
| | - Xianzhen Li
- School of Biological Engineering, Dalian Polytechnic University, Ganjingziqu, Dalian, 116034, People's Republic of China.
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The Linker Region Promotes Activity and Binding Efficiency of Modular LPMO towards Polymeric Substrate. Microbiol Spectr 2022; 10:e0269721. [PMID: 35080440 PMCID: PMC8791183 DOI: 10.1128/spectrum.02697-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) mediate oxidative degradation of plant polysaccharides. The genes encoding LPMOs are most commonly arranged with one catalytic domain, while a few are found tethered to additional noncatalytic units, i.e., cellulase linker and carbohydrate-binding module (CBM). The presence of CBM is known to facilitate catalysis by directing the enzymes toward cellulosic polymer, while the role of linkers is poorly understood. Based on limited experimental evidence, linkers are believed to serve merely as flexible spacers between the structured domains. Thus, this study aims to unravel the role of the linker regions present in LPMO sequences. For this, we analyzed the genome of Botrytis cinerea and found 9 genes encoding cellulose lytic monooxygenases (AA9 family), of which BcAA9C was overexpressed in cellulose-inducible conditions. We designed variants of flLPMO (full-length enzyme) with truncation of either linker or CBM to examine the role of linker in activity, binding, and thermal stability of the associated monooxygenase. Biochemical assays predicted that the deletion of linker does not impact the potential of flLPMO for catalyzing the oxidation of Amplex Red, but that it does have a major influence on the capability of flLPMO to degrade recalcitrant polysaccharide substrate. Langmuir isotherm and SEM analysis demonstrated that linker domain aids in polysaccharide binding during flLPMO-mediated deconstruction of plant cell wall. Interestingly, linker domain was also found to contribute toward the thermostability of flLPMO. Overall, our study reveals that linker is not merely a spacer, but plays a key role in LPMO-mediated biomass fibrillation; these findings are broadly applicable to other polysaccharide-degrading enzymes. IMPORTANCE The polysaccharide-disintegrating carbohydrate-active enzymes (CAZymes) are often found with multimodular architecture, where the catalytic domain is connected to an accessory CBM domain with the help of a flexible linker region. So far, the linker has been understood merely as a flexible spacer between the two domains. Therefore, the current study is designed to determine the role of linker in polysaccharide fibrillation. To conceive this study, we have selected LPMO as a model enzyme, as it is not only an industrially relevant enzyme but it also harbors a catalytic domain, linker region, and CBM domain. The present study highlighted the crucial and indispensable role of the linker region in mediating polysaccharide disintegration. Considering its role in binding, thermostability, and activity toward polysaccharide substrate, we propose linker as a potential candidate for future CAZyme engineering.
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14
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Neis A, da Silva Pinto L. Glycosyl hydrolases family 5, subfamily 5: Relevance and structural insights for designing improved biomass degrading cocktails. Int J Biol Macromol 2021; 193:980-995. [PMID: 34666133 DOI: 10.1016/j.ijbiomac.2021.10.062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 09/29/2021] [Accepted: 10/05/2021] [Indexed: 10/20/2022]
Abstract
Endoglucanases are carbohydrate-degrading enzymes widely used for bioethanol production as part of the enzymatic cocktail. However, family 5 subfamily 5 (GH5_5) endoglucanases are still poorly explored in depth. The Trichoderma reesei representative is the most studied enzyme, presenting catalytic activity in acidic media and mild temperature conditions. Though biochemically similar, its modular structure and synergy with other components vary greatly compared to other GH5_5 members and there is still a lack of specific studies regarding their interaction with other cellulases and application on novel and better mixtures. In this regard, the threedimensional structure elucidation is a highly valuable tool to both uncover basic catalytic mechanisms and implement engineering techniques, proved by the high success rate GH5_5 endoglucanases show. GH5_5 enzymes must be carefully evaluated to fully uncover their potential in biomass-degrading cocktails: the optimal industrial conditions, synergy with other cellulases, structural studies, and enzyme engineering approaches. We aimed to provide the current understanding of these main topics, collecting all available information about characterized GH5_5 endoglucanases function, structure, and bench experiments, in order to suggest future directions to a better application of these enzymes in the industry.
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Affiliation(s)
- Alessandra Neis
- Laboratório de Bioinformática e Proteômica (BioPro Lab), Centro de Desenvolvimento Tecnológico, Campus Universitário, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Caixa Postal 96010-900, Brazil.
| | - Luciano da Silva Pinto
- Laboratório de Bioinformática e Proteômica (BioPro Lab), Centro de Desenvolvimento Tecnológico, Campus Universitário, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Caixa Postal 96010-900, Brazil.
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15
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Tamburrini KC, Terrapon N, Lombard V, Bissaro B, Longhi S, Berrin JG. Bioinformatic Analysis of Lytic Polysaccharide Monooxygenases Reveals the Pan-Families Occurrence of Intrinsically Disordered C-Terminal Extensions. Biomolecules 2021; 11:1632. [PMID: 34827630 PMCID: PMC8615602 DOI: 10.3390/biom11111632] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/26/2021] [Accepted: 10/30/2021] [Indexed: 01/17/2023] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are monocopper enzymes secreted by many organisms and viruses. LPMOs catalyze the oxidative cleavage of different types of polysaccharides and are today divided into eight families (AA9-11, AA13-17) within the Auxiliary Activity enzyme class of the CAZy database. LPMOs minimal architecture encompasses a catalytic domain, to which can be appended a carbohydrate-binding module. Intriguingly, we observed that some LPMO sequences also display a C-terminal extension of varying length not associated with any known function or fold. Here, we analyzed 27,060 sequences from different LPMO families and show that 60% have a C-terminal extension predicted to be intrinsically disordered. Our analysis shows that these disordered C-terminal regions (dCTRs) are widespread in all LPMO families (except AA13) and differ in terms of sequence length and amino-acid composition. Noteworthily, these dCTRs have so far only been observed in LPMOs. LPMO-dCTRs share a common polyampholytic nature and an enrichment in serine and threonine residues, suggesting that they undergo post-translational modifications. Interestingly, dCTRs from AA11 and AA15 are enriched in redox-sensitive, conditionally disordered regions. The widespread occurrence of dCTRs in LPMOs from evolutionarily very divergent organisms, hints at a possible functional role and opens new prospects in the field of LPMOs.
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Affiliation(s)
- Ketty C. Tamburrini
- Architecture et Fonction des Macromolécules Biologiques (AFMB), Centre National de la Recherche Scientifique (CNRS), Aix-Marseille Université (AMU), UMR 7257, 13288 Marseille, France; (K.C.T.); (N.T.); (V.L.)
- Biodiversité et Biotechnologie Fongiques (BBF), French National Institute for Agriculture, Food, and Environment (INRAE), Aix-Marseille Université (AMU), UMR 1163, 13288 Marseille, France;
| | - Nicolas Terrapon
- Architecture et Fonction des Macromolécules Biologiques (AFMB), Centre National de la Recherche Scientifique (CNRS), Aix-Marseille Université (AMU), UMR 7257, 13288 Marseille, France; (K.C.T.); (N.T.); (V.L.)
- Architecture et Fonction des Macromolécules Biologiques (AFMB), French National Institute for Agriculture, Food, and Environment (INRAE), USC 1408, 13288 Marseille, France
| | - Vincent Lombard
- Architecture et Fonction des Macromolécules Biologiques (AFMB), Centre National de la Recherche Scientifique (CNRS), Aix-Marseille Université (AMU), UMR 7257, 13288 Marseille, France; (K.C.T.); (N.T.); (V.L.)
- Architecture et Fonction des Macromolécules Biologiques (AFMB), French National Institute for Agriculture, Food, and Environment (INRAE), USC 1408, 13288 Marseille, France
| | - Bastien Bissaro
- Biodiversité et Biotechnologie Fongiques (BBF), French National Institute for Agriculture, Food, and Environment (INRAE), Aix-Marseille Université (AMU), UMR 1163, 13288 Marseille, France;
| | - Sonia Longhi
- Architecture et Fonction des Macromolécules Biologiques (AFMB), Centre National de la Recherche Scientifique (CNRS), Aix-Marseille Université (AMU), UMR 7257, 13288 Marseille, France; (K.C.T.); (N.T.); (V.L.)
| | - Jean-Guy Berrin
- Biodiversité et Biotechnologie Fongiques (BBF), French National Institute for Agriculture, Food, and Environment (INRAE), Aix-Marseille Université (AMU), UMR 1163, 13288 Marseille, France;
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16
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Badruna L, Burlat V, Roblin P, Enjalbert T, Lippens G, Venditto I, O'Donohue MJ, Montanier CY. The Jo-In protein welding system is a relevant tool to create CBM-containing plant cell wall degrading enzymes. N Biotechnol 2021; 65:31-41. [PMID: 34352412 DOI: 10.1016/j.nbt.2021.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 07/27/2021] [Accepted: 07/29/2021] [Indexed: 11/16/2022]
Abstract
Irrespective of their biological origin, most proteins are composed of several elementary domains connected by linkers. These domains are either functionally independent units, or part of larger multidomain structures whose functions are defined by their spatial proximity. Carbohydrate-degrading enzymes provide examples of a range of multidomain structures, in which catalytic protein domains are frequently appended to one or more non-catalytic carbohydrate-binding modules which specifically bind to carbohydrate motifs. While the carbohydrate-binding specificity of these modules is clear, their function is not fully elucidated. Herein, an original approach to tackle the study of carbohydrate-binding modules using the Jo-In biomolecular welding protein pair is presented. To provide a proof of concept, recombinant xylanases appended to two different carbohydrate-binding modules have been created and produced. The data reveal the biochemical properties of four xylanase variants and provide the basis for correlating enzyme activity to structural properties and to the nature of the substrate and the ligand specificity of the appended carbohydrate-binding module. It reveals that specific spatial arrangements favour activity on soluble polymeric substrates and that activity on such substrates does not predict the behaviour of multimodular enzymes on insoluble plant cell wall samples. The results highlight that the Jo-In protein welding system is extremely useful to design multimodular enzyme systems, especially to create rigid conformations that decrease the risk of intermodular interference. Further work on Jo-In will target the introduction of varying degrees of flexibility, providing the means to study this property and the way it may influence multimodular enzyme functions.
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Affiliation(s)
- Louise Badruna
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Vincent Burlat
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, Toulouse INP, 24 chemin de Borde Rouge, 31320, Auzeville-Tolosane, France
| | - Pierre Roblin
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Thomas Enjalbert
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Guy Lippens
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Immacolata Venditto
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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17
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Gado JE, Harrison BE, Sandgren M, Ståhlberg J, Beckham GT, Payne CM. Machine learning reveals sequence-function relationships in family 7 glycoside hydrolases. J Biol Chem 2021; 297:100931. [PMID: 34216620 PMCID: PMC8329511 DOI: 10.1016/j.jbc.2021.100931] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 06/18/2021] [Accepted: 06/29/2021] [Indexed: 11/28/2022] Open
Abstract
Family 7 glycoside hydrolases (GH7) are among the principal enzymes for cellulose degradation in nature and industrially. These enzymes are often bimodular, including a catalytic domain and carbohydrate-binding module (CBM) attached via a flexible linker, and exhibit an active site that binds cello-oligomers of up to ten glucosyl moieties. GH7 cellulases consist of two major subtypes: cellobiohydrolases (CBH) and endoglucanases (EG). Despite the critical importance of GH7 enzymes, there remain gaps in our understanding of how GH7 sequence and structure relate to function. Here, we employed machine learning to gain data-driven insights into relationships between sequence, structure, and function across the GH7 family. Machine-learning models, trained only on the number of residues in the active-site loops as features, were able to discriminate GH7 CBHs and EGs with up to 99% accuracy, demonstrating that the lengths of loops A4, B2, B3, and B4 strongly correlate with functional subtype across the GH7 family. Classification rules were derived such that specific residues at 42 different sequence positions each predicted the functional subtype with accuracies surpassing 87%. A random forest model trained on residues at 19 positions in the catalytic domain predicted the presence of a CBM with 89.5% accuracy. Our machine learning results recapitulate, as top-performing features, a substantial number of the sequence positions determined by previous experimental studies to play vital roles in GH7 activity. We surmise that the yet-to-be-explored sequence positions among the top-performing features also contribute to GH7 functional variation and may be exploited to understand and manipulate function.
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Affiliation(s)
- Japheth E Gado
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA; Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Brent E Harrison
- Department of Computer Science, University of Kentucky, Lexington, Kentucky, USA
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Gregg T Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Christina M Payne
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA.
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18
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Clerc I, Sagar A, Barducci A, Sibille N, Bernadó P, Cortés J. The diversity of molecular interactions involving intrinsically disordered proteins: A molecular modeling perspective. Comput Struct Biotechnol J 2021; 19:3817-3828. [PMID: 34285781 PMCID: PMC8273358 DOI: 10.1016/j.csbj.2021.06.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 01/15/2023] Open
Abstract
Intrinsically Disordered Proteins and Regions (IDPs/IDRs) are key components of a multitude of biological processes. Conformational malleability enables IDPs/IDRs to perform very specialized functions that cannot be accomplished by globular proteins. The functional role for most of these proteins is related to the recognition of other biomolecules to regulate biological processes or as a part of signaling pathways. Depending on the extent of disorder, the number of interacting sites and the type of partner, very different architectures for the resulting assemblies are possible. More recently, molecular condensates with liquid-like properties composed of multiple copies of IDPs and nucleic acids have been proven to regulate key processes in eukaryotic cells. The structural and kinetic details of disordered biomolecular complexes are difficult to unveil experimentally due to their inherent conformational heterogeneity. Computational approaches, alone or in combination with experimental data, have emerged as unavoidable tools to understand the functional mechanisms of this elusive type of assemblies. The level of description used, all-atom or coarse-grained, strongly depends on the size of the molecular systems and on the timescale of the investigated mechanism. In this mini-review, we describe the most relevant architectures found for molecular interactions involving IDPs/IDRs and the computational strategies applied for their investigation.
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Affiliation(s)
- Ilinka Clerc
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Amin Sagar
- Centre de Biochimie Structurale, INSERM, CNRS, Université de Montpellier, France
| | - Alessandro Barducci
- Centre de Biochimie Structurale, INSERM, CNRS, Université de Montpellier, France
| | - Nathalie Sibille
- Centre de Biochimie Structurale, INSERM, CNRS, Université de Montpellier, France
| | - Pau Bernadó
- Centre de Biochimie Structurale, INSERM, CNRS, Université de Montpellier, France
| | - Juan Cortés
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
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19
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Higasi PMR, Velasco JA, Pellegrini VOA, de Araújo EA, França BA, Keller MB, Labate CA, Blossom BM, Segato F, Polikarpov I. Light-stimulated T. thermophilus two-domain LPMO9H: Low-resolution SAXS model and synergy with cellulases. Carbohydr Polym 2021; 260:117814. [PMID: 33712158 DOI: 10.1016/j.carbpol.2021.117814] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 02/06/2021] [Accepted: 02/10/2021] [Indexed: 12/19/2022]
Abstract
Lytic polysaccharide monooxygenases (LPMOs), monocopper enzymes that oxidatively cleave recalcitrant polysaccharides, have important biotechnological applications. Thermothelomyces thermophilus is a rich source of biomass-active enzymes, including many members from auxiliary activities family 9 LPMOs. Here, we report biochemical and structural characterization of recombinant TtLPMO9H which oxidizes cellulose at the C1 and C4 positions and shows enhanced activity in light-driven catalysis assays. TtLPMO9H also shows activity against xyloglucan. The addition of TtLPMO9H to endoglucanases from four different glucoside hydrolase families (GH5, GH12, GH45 and GH7) revealed that the product formation was remarkably increased when TtLPMO9H was combined with GH7 endoglucanase. Finally, we determind the first low resolution small-angle X-ray scattering model of the two-domain TtLPMO9H in solution that shows relative positions of its two functional domains and a conformation of the linker peptide, which can be relevant for the catalytic oxidation of cellulose and xyloglucan.
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Affiliation(s)
- Paula M R Higasi
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense 400, São Carlos, São Paulo, Brazil
| | - Josman A Velasco
- Lorena School of Engineering, University of São Paulo, Estrada Municipal do Campinho s/n, Lorena, São Paulo, Brazil
| | - Vanessa O A Pellegrini
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense 400, São Carlos, São Paulo, Brazil
| | - Evandro A de Araújo
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense 400, São Carlos, São Paulo, Brazil
| | - Bruno Alves França
- Lorena School of Engineering, University of São Paulo, Estrada Municipal do Campinho s/n, Lorena, São Paulo, Brazil
| | - Malene B Keller
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - Carlos A Labate
- Luiz de Queiroz College of Agriculture, University of São Paulo, Av. Pádua Dias 11, Piracicaba, São Paulo, Brazil
| | - Benedikt M Blossom
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - Fernando Segato
- Lorena School of Engineering, University of São Paulo, Estrada Municipal do Campinho s/n, Lorena, São Paulo, Brazil
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, Av. Trabalhador São-carlense 400, São Carlos, São Paulo, Brazil.
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20
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Zhang H, Wang Y, Brunecky R, Yao B, Xie X, Zheng F, Luo H. A Swollenin From Talaromyces leycettanus JCM12802 Enhances Cellulase Hydrolysis Toward Various Substrates. Front Microbiol 2021; 12:658096. [PMID: 33854492 PMCID: PMC8039133 DOI: 10.3389/fmicb.2021.658096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/10/2021] [Indexed: 12/02/2022] Open
Abstract
Swollenins exist within some fungal species and are candidate accessory proteins for the biodegradation of cellulosic substrates. Here, we describe the identification of a swollenin gene, Tlswo, in Talaromyces leycettanus JCM12802. Tlswo was successfully expressed in both Trichoderma reesei and Pichia pastoris. Assay results indicate that TlSWO is capable of releasing reducing sugars from lichenan, barley β-glucan, carboxymethyl cellulose sodium (CMC-Na) and laminarin. The specific activity of TlSWO toward lichenan, barley β-glucan, carboxymethyl cellulose sodium (CMC-Na) and laminarin is 9.0 ± 0.100, 8.9 ± 0.100, 2.3 ± 0.002 and 0.79 ± 0.002 U/mg, respectively. Additionally, TlSWO had disruptive activity on Avicel and a synergistic effect with cellobiohydrolases, increasing the activity on pretreated corn stover by up to 72.2%. The functional diversity of TlSWO broadens its applicability in experimental settings, and indicating that it may be a promising candidate for future industrial applications.
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Affiliation(s)
- Honghai Zhang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuan Wang
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Roman Brunecky
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Bin Yao
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiangming Xie
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Fei Zheng
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Huiying Luo
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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21
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Deletion of a Peptidylprolyl Isomerase Gene Results in the Inability of Caldicellulosiruptor bescii To Grow on Crystalline Cellulose without Affecting Protein Glycosylation or Growth on Soluble Substrates. Appl Environ Microbiol 2020; 86:AEM.00909-20. [PMID: 32769195 DOI: 10.1128/aem.00909-20] [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: 04/16/2020] [Accepted: 07/30/2020] [Indexed: 11/20/2022] Open
Abstract
Caldicellulosiruptor bescii secretes a large number of complementary multifunctional enzymes with unique activities for biomass deconstruction. The most abundant enzymes in the C. bescii secretome are found in a unique gene cluster containing a glycosyl transferase (GT39) and a putative peptidyl prolyl cis-trans isomerase. Deletion of the glycosyl transferase in this cluster resulted in loss of detectable protein glycosylation in C. bescii, and its activity has been shown to be responsible for the glycosylation of the proline-threonine rich linkers found in many of the multifunctional cellulases. The presence of a putative peptidyl prolyl cis-trans isomerase within this gene cluster suggested that it might also play a role in cellulase modification. Here, we identify this gene as a putative prsA prolyl cis-trans isomerase. Deletion of prsA2 leads to the inability of C. bescii to grow on insoluble substrates such as Avicel, the model cellulose substrate, while exhibiting no differences in phenotype with the wild-type strain on soluble substrates. Finally, we provide evidence that the prsA2 gene is likely needed to increase solubility of multifunctional cellulases and that this unique gene cluster was likely acquired by members of the Caldicellulosiruptor genus with a group of genes to optimize the production and activity of multifunctional cellulases.IMPORTANCE Caldicellulosiruptor has the ability to digest complex plant biomass without pretreatment and have been engineered to convert biomass, a sustainable, carbon neutral substrate, to fuels. Their strategy for deconstructing plant cell walls relies on an interesting class of cellulases consisting of multiple catalytic modules connected by linker regions and carbohydrate binding modules. The best studied of these enzymes, CelA, has a unique deconstruction mechanism. CelA is located in a cluster of genes that likely allows for optimal expression, secretion, and activity. One of the genes in this cluster is a putative isomerase that modifies the CelA protein. In higher eukaryotes, these isomerases are essential for the proper folding of glycoproteins in the endoplasmic reticulum, but little is known about the role of isomerization in cellulase activity. We show that the stability and activity of CelA is dependent on the activity of this isomerase.
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22
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Forsberg Z, Stepnov AA, Nærdal GK, Klinkenberg G, Eijsink VGH. Engineering lytic polysaccharide monooxygenases (LPMOs). Methods Enzymol 2020; 644:1-34. [PMID: 32943141 DOI: 10.1016/bs.mie.2020.04.052] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are mono-copper enzymes that catalyze the hydroxylation of glycosidic bonds found in the most abundant and recalcitrant polysaccharides on Earth. Since their discovery in 2010, these enzymes have received extensive attention in both fundamental and applied research due to their remarkable oxidative power and synergistic interplay with hydrolytic enzymes. The harsh and unnatural conditions used in industrial enzymatic saccharification processes and the sensitivity of LPMOs for damage induced by reactive oxygen species call for enzyme engineering to develop LPMOs to become robust industrial biocatalysts. Other engineering targets include improved catalytic activity, adjusted substrate specificity and the introduction of completely new activities. Reaching these targets not only requires appropriate methods for measuring enzyme activity, but also requires in-depth knowledge of the active site and the reaction mechanism, which is yet to be achieved in the LPMO field. Here we describe what has been done in the LPMO engineering field so far. Furthermore, we address the difficulties involved in properly assessing LPMO functionality, which are due to common side reactions taking place in LPMO reactions and which complicate screening methods.
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Affiliation(s)
- Zarah Forsberg
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway
| | - Anton A Stepnov
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway
| | - Guro Kruge Nærdal
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Geir Klinkenberg
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway.
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Gusakov AV, Uporov IV, Sinitsyna OA. Molecular dynamics simulations of two GH74 endo-processive xyloglucanases and the mutated variants to understand better the mechanism of the enzyme action. Biochim Biophys Acta Gen Subj 2020; 1864:129721. [PMID: 32866595 DOI: 10.1016/j.bbagen.2020.129721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/14/2020] [Accepted: 08/21/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND GH74 xyloglucanases are composed of two separate domains connected by two unstructured peptides. Previously, a hypothesis was made that the movement of domains may affect the enzyme mechanism of catalysis. METHODS The molecular dynamics (MD) simulations of endo-processive xyloglucanases from Paenibacillus odorifer (PoGH74cat) and Myceliophthora thermophila (MtXeg74A) were carried out. RESULTS MD simulations for both enzymes in complex with XXLG and XGXXLG oligosaccharides confirmed the possibility of domain movement. In the case of MtXeg74A, changes in the distances between Cα atoms of aromatic residues involved in xyloglucan binding in -3 and +3 subsites of the active site cleft and those of selected residues on the opposite side of the cleft reached values up to 10-12 Å. For PoGH74cat the conformational changes were less pronounced. In MtXeg74A variants, the deletion of loop 1, which partially closes the entrance to the cleft, and the additional double mutation of two Trp residues in +3 and +5 subsites caused the enhanced mobility of the XGXXLG and also induced changes in topography of the cleft. CONCLUSIONS These findings demonstrate the possibility of existence of GH74 xyloglucanases in a more open and more closed enzyme conformation. The enzyme in an open conformation may more easily accommodate the branched polysaccharide, while its transition to the closed conformation, together with loop 1 function, should aid processivity. GENERAL SIGNIFICANCE Our results provide an insight into a mechanism of action of GH74 xyloglucanases and may be useful for discussing the catalytic mechanisms of glycoside hydrolases from other families.
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Affiliation(s)
- Alexander V Gusakov
- Department of Chemistry, M. V. Lomonosov Moscow State University, Vorobyovy Gory 1/11, Moscow 119991, Russia.
| | - Igor V Uporov
- Department of Chemistry, M. V. Lomonosov Moscow State University, Vorobyovy Gory 1/11, Moscow 119991, Russia
| | - Olga A Sinitsyna
- Department of Chemistry, M. V. Lomonosov Moscow State University, Vorobyovy Gory 1/11, Moscow 119991, Russia
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24
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A linker of the proline-threonine repeating motif sequence is bimodal. J Mol Model 2020; 26:178. [PMID: 32562031 DOI: 10.1007/s00894-020-04434-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 06/02/2020] [Indexed: 10/24/2022]
Abstract
The linker of the endoglucanase from Xanthomonas campestris pv. campestris ((PT)12) has a specific sequence, a repeating proline-threonine motif. In order to understand its role, it has been compared to a regular sequence linker, in this work-the cellobiohydrolase 2 from Trichoderma reesei (CBH2). Elastic properties of the two linkers have been estimated by calculating free energy profile along the linker length from an enhanced sampling molecular dynamics simulation. The (PT)12 exhibits more pronounced elastic behaviour than CBH2. The PT repeating motif results in a two-mode energy profile which could be very useful in the enzyme motions along the substrate during hydrolytic catalysis.
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25
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Wilken SE, Seppälä S, Lankiewicz TS, Saxena M, Henske JK, Salamov AA, Grigoriev IV, O’Malley MA. Genomic and proteomic biases inform metabolic engineering strategies for anaerobic fungi. Metab Eng Commun 2020; 10:e00107. [PMID: 31799118 PMCID: PMC6883316 DOI: 10.1016/j.mec.2019.e00107] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 10/24/2019] [Accepted: 11/04/2019] [Indexed: 12/22/2022] Open
Abstract
Anaerobic fungi (Neocallimastigomycota) are emerging non-model hosts for biotechnology due to their wealth of biomass-degrading enzymes, yet tools to engineer these fungi have not yet been established. Here, we show that the anaerobic gut fungi have the most GC depleted genomes among 443 sequenced organisms in the fungal kingdom, which has ramifications for heterologous expression of genes as well as for emerging CRISPR-based genome engineering approaches. Comparative genomic analyses suggest that anaerobic fungi may contain cellular machinery to aid in sexual reproduction, yet a complete mating pathway was not identified. Predicted proteomes of the anaerobic fungi also contain an unusually large fraction of proteins with homopolymeric amino acid runs consisting of five or more identical consecutive amino acids. In particular, threonine runs are especially enriched in anaerobic fungal carbohydrate active enzymes (CAZymes) and this, together with a high abundance of predicted N-glycosylation motifs, suggests that gut fungal CAZymes are heavily glycosylated, which may impact heterologous production of these biotechnologically useful enzymes. Finally, we present a codon optimization strategy to aid in the development of genetic engineering tools tailored to these early-branching anaerobic fungi.
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Affiliation(s)
- St. Elmo Wilken
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Susanna Seppälä
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Thomas S. Lankiewicz
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
- Department of Evolution Ecology and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Mohan Saxena
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - John K. Henske
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Asaf A. Salamov
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA, 94598, USA
| | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA, 94598, USA
| | - Michelle A. O’Malley
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
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Bahaman AH, Wahab RA, Abdul Hamid AA, Abd Halim KB, Kaya Y. Molecular docking and molecular dynamics simulations studies on β-glucosidase and xylanase Trichoderma asperellum to predict degradation order of cellulosic components in oil palm leaves for nanocellulose preparation. J Biomol Struct Dyn 2020; 39:2628-2641. [DOI: 10.1080/07391102.2020.1751713] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Aina Hazimah Bahaman
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, UTM Johor Bahru, Johor, Malaysia
- Enzyme Technology and Green Synthesis Group, Universiti Teknologi Malaysia, UTM Johor Bahru, Johor, Malaysia
| | - Roswanira Abdul Wahab
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, UTM Johor Bahru, Johor, Malaysia
- Enzyme Technology and Green Synthesis Group, Universiti Teknologi Malaysia, UTM Johor Bahru, Johor, Malaysia
| | - Azzmer Azzar Abdul Hamid
- Department of Biotechnology, Kuliyyah of Science, International Islamic University Malaysia, Kuantan, Malaysia
- Research Unit for Bioinformatics and Computational Biology (RUBIC), Kulliyyah of Science, International Islamic University Malaysia, Pahang, Malaysia
| | - Khairul Bariyyah Abd Halim
- Department of Biotechnology, Kuliyyah of Science, International Islamic University Malaysia, Kuantan, Malaysia
- Research Unit for Bioinformatics and Computational Biology (RUBIC), Kulliyyah of Science, International Islamic University Malaysia, Pahang, Malaysia
| | - Yilmaz Kaya
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayis University, Samsun, Turkey
- Department of Biology, Faculty of Science, Kyrgyz-Turkish Manas University, Bishkek, Kyrgyzstan
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27
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Semenova MV, Gusakov AV, Telitsin VD, Rozhkova AM, Kondratyeva EG, Sinitsyn AP. Purification and characterization of two forms of the homologously expressed lytic polysaccharide monooxygenase (PvLPMO9A) from Penicillium verruculosum. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140297. [DOI: 10.1016/j.bbapap.2019.140297] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/17/2019] [Accepted: 10/04/2019] [Indexed: 10/25/2022]
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28
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Hu B, Zhu M. Reconstitution of cellulosome: Research progress and its application in biorefinery. Biotechnol Appl Biochem 2019; 66:720-730. [DOI: 10.1002/bab.1804] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 08/03/2019] [Indexed: 09/01/2023]
Affiliation(s)
- Bin‐Bin Hu
- Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals School of Biology and Biological Engineering South China University of Technology, Guangzhou Higher Education Mega Center Panyu Guangzhou People's Republic of China
- Yunnan Academy of Tobacco Agricultural Sciences Kunming People's Republic of China
- State Key Laboratory of Pulp and Paper Engineering South China University of Technology Guangzhou People's Republic of China
| | - Ming‐Jun Zhu
- Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals School of Biology and Biological Engineering South China University of Technology, Guangzhou Higher Education Mega Center Panyu Guangzhou People's Republic of China
- State Key Laboratory of Pulp and Paper Engineering South China University of Technology Guangzhou People's Republic of China
- College of Life and Geographic Sciences Kashi University Kashi People's Republic of China
- The Key Laboratory of Ecology and Biological Resources in Yarkand Oasis at Colleges & Universities under the Department of Education of Xinjiang Uygur Autonomous Region Kashi University Kashi People's Republic of China
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29
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Cloning, expression, and characterization of novel GH5 endoglucanases from Thermobifida alba AHK119. J Biosci Bioeng 2019; 127:554-562. [DOI: 10.1016/j.jbiosc.2018.10.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 10/13/2018] [Accepted: 10/16/2018] [Indexed: 01/01/2023]
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30
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Wang Z, Zhang T, Long L, Ding S. Altering the linker in processive GH5 endoglucanase 1 modulates lignin binding and catalytic properties. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:332. [PMID: 30568732 PMCID: PMC6297974 DOI: 10.1186/s13068-018-1333-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND The non-productive adsorption of cellulases onto lignin in biomass is a key issue for the biofuel process economy. It would be helpful to reduce the inhibitory effect of lignin on enzymatic hydrolysis by engineering weak lignin-binding cellulases. Cellulase linkers are highly divergent in their lengths, compositions, and glycosylations. Numerous studies have revealed that linkers can facilitate optimal interactions between structured domains. Recently, efforts have focused on the contributions and mechanisms of carbohydrate-binding modules and catalytic domains that affect lignin affinity and processivity of cellulases, but our understanding of the effects of the linker regions on lignin adsorption and processivity of GH5 processive endoglucanases is still limited. RESULTS Eight GH5 endoglucanase 1 variants of varying length, flexibility, and sequence in the linker region were constructed. Their characteristics were then compared to the wild-type enzyme (EG1). Remarkably, significant differences in the lignin adsorption profiles and processivities were observed for EG1 and other variants. Our studies suggest that either the length or the specific amino acid composition of the linker has a prominent influence on the lignin-binding affinity of the enzymes. Comparatively, the processivity may depend primarily on the length of the linker and less so on the specific amino acid composition. EG1-ApCel5A, a variant with better performance in enzymatic hydrolysis in the presence of lignin, was obtained by replacing a longer, flexible linker. In total, up to between 28.2 and 30.1% more reducing sugars were generated from filter paper by EG1-ApCel5A in the presence of lignin compared to EG1. CONCLUSIONS Our results highlight the relevance of the linker region in the lignin adsorption and processivity of a processive endoglucanase. Our findings suggest that the linker region may be used as a target for the design of more active and weaker lignin-binding cellulases.
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Affiliation(s)
- Zhen Wang
- The Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu China
| | - Tianrui Zhang
- The Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu China
| | - Liangkun Long
- The Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu China
| | - Shaojun Ding
- The Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu China
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31
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Li P, Zhang C, Xu D. Molecular dynamics investigations of cello-oligosaccharide recognition by Cel9G-CBM3c from Clostridium cellulovorans. Phys Chem Chem Phys 2018; 20:5235-5245. [PMID: 29399685 DOI: 10.1039/c7cp07175b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The processive mechanism of cellulases against cellulose represents one of the key mechanisms in the conversion of biomass. A reliable model of substrate binding in a multidomain cellulase is a prerequisite for fully understanding this mechanism. In this study, the specificity of the recognition of the polysaccharide by the multidomain endoglucanase Cel9G from Clostridium cellulovorans was investigated by molecular dynamics simulations. Aromatic ring-containing residues were found to be critical for stabilizing the substrate. The calculated subtotal contributions of polar residues close to the active site, e.g., D58, E244, R315 and D420, also have some critical functions in substrate binding. Unlike other members of the carbohydrate-binding module family, CBM3c alone is shown not to bind cellulose very well, which is also consistent with experimental conclusions.
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Affiliation(s)
- Penghui Li
- MOE Key Laboratory of Green Chemistry, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, People's Republic of China.
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32
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Du J, Zhang X, Li X, Zhao J, Liu G, Gao B, Qu Y. The cellulose binding region in Trichoderma reesei cellobiohydrolase I has a higher capacity in improving crystalline cellulose degradation than that of Penicillium oxalicum. BIORESOURCE TECHNOLOGY 2018; 266:19-25. [PMID: 29940438 DOI: 10.1016/j.biortech.2018.06.050] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 06/16/2018] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
Commercial cellulase preparations for lignocellulose bioconversion are mainly produced by the fungus Trichoderma reesei. The maximum cellulose conversion of T. reesei cellulase mixture was 15%-20% higher than that of Penicillium oxalicum in the hydrolysis of corncob residue and Avicel. Nevertheless, both preparations hydrolyzed more than 92% of cellulose in NaOH-mercerized Avicel. When added to Avicel hydrolysis residue that was less reactive to P. oxalicum cellulases, cellobiohydrolase I (CBH I) from T. reesei resulted in a higher cellulose conversion than its homologous proteins from P. oxalicum and Aspergillus niger at the same protein loadings. Further domain exchange experiment attributed the high hydrolytic efficiency of T. reesei CBH I to its inter-domain linker and cellulose-binding domain. The results in part explained the superior performance of T. reesei cellulases on the degradation of native crystalline cellulose, and highlighted the important role of cellulose-binding region in determining the degree of hydrolysis by cellulases.
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Affiliation(s)
- Jian Du
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China
| | - Xiu Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China; Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, Shandong, PR China.
| | - Baoyu Gao
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, Shandong, PR China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, Shandong, PR China
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Lyu Q, Zhang K, Zhu Q, Li Z, Liu Y, Fitzek E, Yohe T, Zhao L, Li W, Liu T, Yin Y, Liu W. Structural and biochemical characterization of a multidomain alginate lyase reveals a novel role of CBM32 in CAZymes. Biochim Biophys Acta Gen Subj 2018; 1862:1862-1869. [DOI: 10.1016/j.bbagen.2018.05.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/29/2018] [Accepted: 05/31/2018] [Indexed: 01/27/2023]
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Courtade G, Forsberg Z, Heggset EB, Eijsink VGH, Aachmann FL. The carbohydrate-binding module and linker of a modular lytic polysaccharide monooxygenase promote localized cellulose oxidation. J Biol Chem 2018; 293:13006-13015. [PMID: 29967065 DOI: 10.1074/jbc.ra118.004269] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 06/23/2018] [Indexed: 01/24/2023] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that catalyze the oxidative cleavage of polysaccharides such as cellulose and chitin, a feature that makes them key tools in industrial biomass conversion processes. The catalytic domains of a considerable fraction of LPMOs and other carbohydrate-active enzymes (CAZymes) are tethered to carbohydrate-binding modules (CBMs) by flexible linkers. These linkers preclude X-ray crystallographic studies, and the functional implications of these modular assemblies remain partly unknown. Here, we used NMR spectroscopy to characterize structural and dynamic features of full-length modular ScLPMO10C from Streptomyces coelicolor We observed that the linker is disordered and extended, creating distance between the CBM and the catalytic domain and allowing these domains to move independently of each other. Functional studies with cellulose nanofibrils revealed that most of the substrate-binding affinity of full-length ScLPMO10C resides in the CBM. Comparison of the catalytic performance of full-length ScLPMO10C and its isolated catalytic domain revealed that the CBM is beneficial for LPMO activity at lower substrate concentrations and promotes localized and repeated oxidation of the substrate. Taken together, these results provide a mechanistic basis for understanding the interplay between catalytic domains linked to CBMs in LPMOs and CAZymes in general.
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Affiliation(s)
- Gaston Courtade
- From NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway
| | - Zarah Forsberg
- the Faculty of Chemistry, Biotechnology and Food Science, NMBU Norwegian University of Life Sciences, N-1432 Ås, Norway, and
| | | | - Vincent G H Eijsink
- the Faculty of Chemistry, Biotechnology and Food Science, NMBU Norwegian University of Life Sciences, N-1432 Ås, Norway, and
| | - Finn L Aachmann
- From NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway,
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Guerriero G, Sergeant K, Legay S, Hausman JF, Cauchie HM, Ahmad I, Siddiqui KS. Novel Insights from Comparative In Silico Analysis of Green Microalgal Cellulases. Int J Mol Sci 2018; 19:E1782. [PMID: 29914107 PMCID: PMC6032398 DOI: 10.3390/ijms19061782] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/08/2018] [Accepted: 06/08/2018] [Indexed: 11/24/2022] Open
Abstract
The assumption that cellulose degradation and assimilation can only be carried out by heterotrophic organisms was shattered in 2012 when it was discovered that the unicellular green alga, Chlamydomonas reinhardtii (Cr), can utilize cellulose for growth under CO₂-limiting conditions. Publications of genomes/transcriptomes of the colonial microalgae, Gonium pectorale (Gp) and Volvox carteri (Vc), between 2010⁻2016 prompted us to look for cellulase genes in these algae and to compare them to cellulases from bacteria, fungi, lower/higher plants, and invertebrate metazoans. Interestingly, algal catalytic domains (CDs), belonging to the family GH9, clustered separately and showed the highest (33⁻42%) and lowest (17⁻36%) sequence identity with respect to cellulases from invertebrate metazoans and bacteria, respectively, whereas the identity with cellulases from plants was only 27⁻33%. Based on comparative multiple alignments and homology models, the domain arrangement and active-site architecture of algal cellulases are described in detail. It was found that all algal cellulases are modular, consisting of putative novel cysteine-rich carbohydrate-binding modules (CBMs) and proline/serine-(PS) rich linkers. Two genes were found to encode a protein with a putative Ig-like domain and a cellulase with an unknown domain, respectively. A feature observed in one cellulase homolog from Gp and shared by a spinach cellulase is the existence of two CDs separated by linkers and with a C-terminal CBM. Dockerin and Fn-3-like domains, typically found in bacterial cellulases, are absent in algal enzymes. The targeted gene expression analysis shows that two Gp cellulases consisting, respectively, of a single and two CDs were upregulated upon filter paper addition to the medium.
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Affiliation(s)
- Gea Guerriero
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Kjell Sergeant
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Sylvain Legay
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Jean-Francois Hausman
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Henry-Michel Cauchie
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Irshad Ahmad
- Life Sciences Department, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
| | - Khawar Sohail Siddiqui
- Life Sciences Department, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
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Biochemical characterization, low-resolution SAXS structure and an enzymatic cleavage pattern of BlCel48 from Bacillus licheniformis. Int J Biol Macromol 2018; 111:302-310. [DOI: 10.1016/j.ijbiomac.2017.12.138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 12/17/2017] [Accepted: 12/25/2017] [Indexed: 12/12/2022]
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37
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Prates ET, Guan X, Li Y, Wang X, Chaffey PK, Skaf MS, Crowley MF, Tan Z, Beckham GT. The impact of O-glycan chemistry on the stability of intrinsically disordered proteins. Chem Sci 2018; 9:3710-3715. [PMID: 29780502 PMCID: PMC5939190 DOI: 10.1039/c7sc05016j] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/19/2018] [Indexed: 01/14/2023] Open
Abstract
Protein glycosylation is a diverse post-translational modification that serves myriad biological functions. O-linked glycans in particular vary widely in extent and chemistry in eukaryotes, with secreted proteins from fungi and yeast commonly exhibiting O-mannosylation in intrinsically disordered regions of proteins, likely for proteolysis protection, among other functions. However, it is not well understood why mannose is often the preferred glycan, and more generally, if the neighboring protein sequence and glycan have coevolved to protect against proteolysis in glycosylated intrinsically disordered proteins (IDPs). Here, we synthesized variants of a model IDP, specifically a natively O-mannosylated linker from a fungal enzyme, with α-O-linked mannose, glucose, and galactose moieties, along with a non-glycosylated linker. Upon exposure to thermolysin, O-mannosylation, by far, provides the highest extent of proteolysis protection. To explain this observation, extensive molecular dynamics simulations were conducted, revealing that the axial configuration of the C2-hydroxyl group (2-OH) of α-mannose adjacent to the glycan-peptide bond strongly influences the conformational features of the linker. Specifically, α-mannose restricts the torsions of the IDP main chain more than other glycans whose equatorial 2-OH groups exhibit interactions that favor perpendicular glycan-protein backbone orientation. We suggest that IDP stiffening due to O-mannosylation impairs protease action, with contributions from protein-glycan interactions, protein flexibility, and protein stability. Our results further imply that resistance to proteolysis is an important driving force for evolutionary selection of α-mannose in eukaryotic IDPs, and more broadly, that glycan motifs for proteolysis protection likely coevolve with the protein sequence to which they attach.
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Affiliation(s)
- Erica T Prates
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , CO 80403 , USA .
- Institute of Chemistry , Center for Computational Engineering and Sciences , University of Campinas , 13084-862 , SP , Brazil
| | - Xiaoyang Guan
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Yaohao Li
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Xinfeng Wang
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Patrick K Chaffey
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Munir S Skaf
- Institute of Chemistry , Center for Computational Engineering and Sciences , University of Campinas , 13084-862 , SP , Brazil
| | - Michael F Crowley
- Biosciences Center , National Renewable Energy Laboratory , Golden , CO 80403 , USA .
| | - Zhongping Tan
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Gregg T Beckham
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , CO 80403 , USA .
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The PT/S-Box of Modular Cellulase AcCel12B Plays a Key Role in the Hydrolysis of Insoluble Cellulose. Catalysts 2018. [DOI: 10.3390/catal8030123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Meier KK, Jones SM, Kaper T, Hansson H, Koetsier MJ, Karkehabadi S, Solomon EI, Sandgren M, Kelemen B. Oxygen Activation by Cu LPMOs in Recalcitrant Carbohydrate Polysaccharide Conversion to Monomer Sugars. Chem Rev 2018; 118:2593-2635. [PMID: 29155571 PMCID: PMC5982588 DOI: 10.1021/acs.chemrev.7b00421] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Natural carbohydrate polymers such as starch, cellulose, and chitin provide renewable alternatives to fossil fuels as a source for fuels and materials. As such, there is considerable interest in their conversion for industrial purposes, which is evidenced by the established and emerging markets for products derived from these natural polymers. In many cases, this is achieved via industrial processes that use enzymes to break down carbohydrates to monomer sugars. One of the major challenges facing large-scale industrial applications utilizing natural carbohydrate polymers is rooted in the fact that naturally occurring forms of starch, cellulose, and chitin can have tightly packed organizations of polymer chains with low hydration levels, giving rise to crystalline structures that are highly recalcitrant to enzymatic degradation. The topic of this review is oxidative cleavage of carbohydrate polymers by lytic polysaccharide mono-oxygenases (LPMOs). LPMOs are copper-dependent enzymes (EC 1.14.99.53-56) that, with glycoside hydrolases, participate in the degradation of recalcitrant carbohydrate polymers. Their activity and structural underpinnings provide insights into biological mechanisms of polysaccharide degradation.
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Affiliation(s)
- Katlyn K. Meier
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Stephen M. Jones
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Thijs Kaper
- DuPont Industrial Biosciences, 925 Page Mill Road, Palo Alto, California 94304, United States
| | - Henrik Hansson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
| | - Martijn J. Koetsier
- DuPont Industrial Biosciences, Netherlands, Nieuwe Kanaal 7-S, 6709 PA Wageningen, The Netherlands
| | - Saeid Karkehabadi
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
| | - Edward I. Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
| | - Bradley Kelemen
- DuPont Industrial Biosciences, 925 Page Mill Road, Palo Alto, California 94304, United States
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40
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Kadowaki MAS, Higasi P, de Godoy MO, Prade RA, Polikarpov I. Biochemical and structural insights into a thermostable cellobiohydrolase from Myceliophthora thermophila. FEBS J 2018; 285:559-579. [PMID: 29222836 DOI: 10.1111/febs.14356] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/20/2017] [Accepted: 12/05/2017] [Indexed: 12/27/2022]
Abstract
Cellobiohydrolases hydrolyze cellulose, a linear polymer with glucose monomers linked exclusively by β-1,4 glycosidic linkages. The widespread hydrogen bonding network tethers individual cellulose polymers forming crystalline cellulose, which prevent the access of hydrolytic enzymes and water molecules. The most abundant enzyme secreted by Myceliophthora thermophila M77 in response to the presence of biomass is the cellobiohydrolase MtCel7A, which is composed by a GH7-catalytic domain (CD), a linker, and a CBM1-type carbohydrate-binding module. GH7 cellobiohydrolases have been studied before, and structural models have been proposed. However, currently available GH7 crystal structures only define separate catalytic domains and/or cellulose-binding modules and do not include the full-length structures that are involved in shaping the catalytic mode of operation. In this study, we determined the 3D structure of catalytic domain using X-ray crystallography and retrieved the full-length enzyme envelope via small-angle X-ray scattering (SAXS) technique. The SAXS data reveal a tadpole-like molecular shape with a rigid linker connecting the CD and CBM. Our biochemical studies show that MtCel7A has higher catalytic efficiency and thermostability as well as lower processivity when compared to the well-studied TrCel7A from Trichoderma reesei. Based on a comparison of the crystallographic structures of CDs and their molecular dynamic simulations, we demonstrate that MtCel7A has considerably higher flexibility than TrCel7A. In particular, loops that cover the active site are more flexible and undergo higher conformational fluctuations, which might account for decreased processivity and enhanced enzymatic efficiency. Our statistical coupling analysis suggests co-evolution of amino acid clusters comprising the catalytic site of MtCel7A, which correlate with the steps in the catalytic cycle of the enzyme. DATABASE The atomic coordinates and structural factors of MtCel7A have been deposited in the Protein Data Bank with accession number 5W11.
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Affiliation(s)
| | - Paula Higasi
- São Carlos Institute of Physics, University of São Paulo, Brazil
| | | | - Rolf A Prade
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, Brazil
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Borisova AS, Eneyskaya EV, Jana S, Badino SF, Kari J, Amore A, Karlsson M, Hansson H, Sandgren M, Himmel ME, Westh P, Payne CM, Kulminskaya AA, Ståhlberg J. Correlation of structure, function and protein dynamics in GH7 cellobiohydrolases from Trichoderma atroviride, T. reesei and T. harzianum. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:5. [PMID: 29344086 PMCID: PMC5766984 DOI: 10.1186/s13068-017-1006-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/23/2017] [Indexed: 05/11/2023]
Abstract
BACKGROUND The ascomycete fungus Trichoderma reesei is the predominant source of enzymes for industrial conversion of lignocellulose. Its glycoside hydrolase family 7 cellobiohydrolase (GH7 CBH) TreCel7A constitutes nearly half of the enzyme cocktail by weight and is the major workhorse in the cellulose hydrolysis process. The orthologs from Trichoderma atroviride (TatCel7A) and Trichoderma harzianum (ThaCel7A) show high sequence identity with TreCel7A, ~ 80%, and represent naturally evolved combinations of cellulose-binding tunnel-enclosing loop motifs, which have been suggested to influence intrinsic cellobiohydrolase properties, such as endo-initiation, processivity, and off-rate. RESULTS The TatCel7A, ThaCel7A, and TreCel7A enzymes were characterized for comparison of function. The catalytic domain of TatCel7A was crystallized, and two structures were determined: without ligand and with thio-cellotriose in the active site. Initial hydrolysis of bacterial cellulose was faster with TatCel7A than either ThaCel7A or TreCel7A. In synergistic saccharification of pretreated corn stover, both TatCel7A and ThaCel7A were more efficient than TreCel7A, although TatCel7A was more sensitive to thermal inactivation. Structural analyses and molecular dynamics (MD) simulations were performed to elucidate important structure/function correlations. Moreover, reverse conservation analysis (RCA) of sequence diversity revealed divergent regions of interest located outside the cellulose-binding tunnel of Trichoderma spp. GH7 CBHs. CONCLUSIONS We hypothesize that the combination of loop motifs is the main determinant for the observed differences in Cel7A activity on cellulosic substrates. Fine-tuning of the loop flexibility appears to be an important evolutionary target in Trichoderma spp., a conclusion supported by the RCA data. Our results indicate that, for industrial use, it would be beneficial to combine loop motifs from TatCel7A with the thermostability features of TreCel7A. Furthermore, one region implicated in thermal unfolding is suggested as a primary target for protein engineering.
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Affiliation(s)
- Anna S. Borisova
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
- B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Orlova Roscha, Gatchina, Leningrad Region 188300 Russia
| | - Elena V. Eneyskaya
- B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Orlova Roscha, Gatchina, Leningrad Region 188300 Russia
| | - Suvamay Jana
- Department of Chemical and Materials Engineering, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046 USA
| | - Silke F. Badino
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Jeppe Kari
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Antonella Amore
- National Renewable Energy Laboratory, Biosciences Center, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Magnus Karlsson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, 750 07 Uppsala, Sweden
| | - Henrik Hansson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
| | - Michael E. Himmel
- National Renewable Energy Laboratory, Biosciences Center, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Peter Westh
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Christina M. Payne
- Department of Chemical and Materials Engineering, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046 USA
- Present Address: Division of Chemical, Bioengineering, Environmental, and Transport Systems, National Science Foundation, Alexandria, VA USA
| | - Anna A. Kulminskaya
- B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Orlova Roscha, Gatchina, Leningrad Region 188300 Russia
- Department of Medical Physics, Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
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42
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Distinct roles of N- and O-glycans in cellulase activity and stability. Proc Natl Acad Sci U S A 2017; 114:13667-13672. [PMID: 29229855 DOI: 10.1073/pnas.1714249114] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In nature, many microbes secrete mixtures of glycoside hydrolases, oxidoreductases, and accessory enzymes to deconstruct polysaccharides and lignin in plants. These enzymes are often decorated with N- and O-glycosylation, the roles of which have been broadly attributed to protection from proteolysis, as the extracellular milieu is an aggressive environment. Glycosylation has been shown to sometimes affect activity, but these effects are not fully understood. Here, we examine N- and O-glycosylation on a model, multimodular glycoside hydrolase family 7 cellobiohydrolase (Cel7A), which exhibits an O-glycosylated carbohydrate-binding module (CBM) and an O-glycosylated linker connected to an N- and O-glycosylated catalytic domain (CD)-a domain architecture common to many biomass-degrading enzymes. We report consensus maps for Cel7A glycosylation that include glycan sites and motifs. Additionally, we examine the roles of glycans on activity, substrate binding, and thermal and proteolytic stability. N-glycan knockouts on the CD demonstrate that N-glycosylation has little impact on cellulose conversion or binding, but does have major stability impacts. O-glycans on the CBM have little impact on binding, proteolysis, or activity in the whole-enzyme context. However, linker O-glycans greatly impact cellulose conversion via their contribution to proteolysis resistance. Molecular simulations predict an additional role for linker O-glycans, namely that they are responsible for maintaining separation between ordered domains when Cel7A is engaged on cellulose, as models predict α-helix formation and decreased cellulose interaction for the nonglycosylated linker. Overall, this study reveals key roles for N- and O-glycosylation that are likely broadly applicable to other plant cell-wall-degrading enzymes.
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43
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Badino SF, Bathke JK, Sørensen TH, Windahl MS, Jensen K, Peters GHJ, Borch K, Westh P. The influence of different linker modifications on the catalytic activity and cellulose affinity of cellobiohydrolase Cel7A from Hypocrea jecorina. Protein Eng Des Sel 2017; 30:495-501. [PMID: 28873985 DOI: 10.1093/protein/gzx036] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 07/04/2017] [Indexed: 12/13/2022] Open
Abstract
Various cellulases consist of a catalytic domain connected to a carbohydrate-binding module (CBM) by a flexible linker peptide. The linker if often strongly O-glycosylated and typically has a length of 20-50 amino acid residues. Functional roles, other than connecting the two folded domains, of the linker and its glycans, have been widely discussed, but experimental evidence remains sparse. One of the most studied cellulose degrading enzymes is the multi-domain cellobiohydrolase Cel7A from Hypocrea jecorina. Here, we designed variants of Cel7A with mutations in the linker region to elucidate the role of the linker. We found that moderate modification of the linker could result in significant changes in substrate affinity and catalytic efficacy. These changes were quite different for different linker variants. Thus, deletion of six residues near the catalytic domain had essentially no effects on enzyme function. Conversely, a substitution of four glycosylation sites near the middle of the linker reduced substrate affinity and increased maximal turnover. The observation of weaker binding provides some support of recent suggestions that linker glycans may be directly involved in substrate interactions. However, a variant with several inserted glycosylation sites near the CBM also showed lower affinity for the substrate compared to the wild-type, and we suggest that substrate interactions of the glycans depend on their exact location as well as other factors such as changes in structure and dynamics of the linker peptide.
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Affiliation(s)
- Silke Flindt Badino
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
| | - Jenny Kim Bathke
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Build. 207, DK-2800 Kgs. Lyngby, Denmark
| | - Trine Holst Sørensen
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
| | - Michael Skovbo Windahl
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Krogshøjvej 36, DK-2880, Bagsværd, Denmark
| | - Günther H J Peters
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Build. 207, DK-2800 Kgs. Lyngby, Denmark
| | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880, Bagsværd, Denmark
| | - Peter Westh
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
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44
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Hansson H, Karkehabadi S, Mikkelsen N, Douglas NR, Kim S, Lam A, Kaper T, Kelemen B, Meier KK, Jones SM, Solomon EI, Sandgren M. High-resolution structure of a lytic polysaccharide monooxygenase from Hypocrea jecorina reveals a predicted linker as an integral part of the catalytic domain. J Biol Chem 2017; 292:19099-19109. [PMID: 28900033 DOI: 10.1074/jbc.m117.799767] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/29/2017] [Indexed: 12/17/2022] Open
Abstract
For decades, the enzymes of the fungus Hypocrea jecorina have served as a model system for the breakdown of cellulose. Three-dimensional structures for almost all H. jecorina cellulose-degrading enzymes are available, except for HjLPMO9A, belonging to the AA9 family of lytic polysaccharide monooxygenases (LPMOs). These enzymes enhance the hydrolytic activity of cellulases and are essential for cost-efficient conversion of lignocellulosic biomass. Here, using structural and spectroscopic analyses, we found that native HjLPMO9A contains a catalytic domain and a family-1 carbohydrate-binding module (CBM1) connected via a linker sequence. A C terminally truncated variant of HjLPMO9A containing 21 residues of the predicted linker was expressed at levels sufficient for analysis. Here, using structural, spectroscopic, and biochemical analyses, we found that this truncated variant exhibited reduced binding to and activity on cellulose compared with the full-length enzyme. Importantly, a 0.95-Å resolution X-ray structure of truncated HjLPMO9A revealed that the linker forms an integral part of the catalytic domain structure, covering a hydrophobic patch on the catalytic AA9 module. We noted that the oxidized catalytic center contains a Cu(II) coordinated by two His ligands, one of which has a His-brace in which the His-1 terminal amine group also coordinates to a copper. The final equatorial position of the Cu(II) is occupied by a water-derived ligand. The spectroscopic characteristics of the truncated variant were not measurably different from those of full-length HjLPMO9A, indicating that the presence of the CBM1 module increases the affinity of HjLPMO9A for cellulose binding, but does not affect the active site.
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Affiliation(s)
- Henrik Hansson
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
| | - Saeid Karkehabadi
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
| | - Nils Mikkelsen
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
| | | | - Steve Kim
- DuPont Industrial Biosciences, Palo Alto, California 94304, and
| | - Anna Lam
- DuPont Industrial Biosciences, Palo Alto, California 94304, and
| | - Thijs Kaper
- DuPont Industrial Biosciences, Palo Alto, California 94304, and
| | - Brad Kelemen
- DuPont Industrial Biosciences, Palo Alto, California 94304, and
| | - Katlyn K Meier
- the Department of Chemistry, Stanford University, Stanford, California 94305
| | - Stephen M Jones
- the Department of Chemistry, Stanford University, Stanford, California 94305
| | - Edward I Solomon
- the Department of Chemistry, Stanford University, Stanford, California 94305
| | - Mats Sandgren
- From the Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden,
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45
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Duan CJ, Huang MY, Pang H, Zhao J, Wu CX, Feng JX. Characterization of a novel theme C glycoside hydrolase family 9 cellulase and its CBM-chimeric enzymes. Appl Microbiol Biotechnol 2017; 101:5723-5737. [DOI: 10.1007/s00253-017-8320-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 04/09/2017] [Accepted: 04/29/2017] [Indexed: 01/27/2023]
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46
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Hüttner S, Klaubauf S, de Vries RP, Olsson L. Characterisation of three fungal glucuronoyl esterases on glucuronic acid ester model compounds. Appl Microbiol Biotechnol 2017; 101:5301-5311. [PMID: 28429057 PMCID: PMC5486812 DOI: 10.1007/s00253-017-8266-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/12/2017] [Accepted: 03/27/2017] [Indexed: 01/07/2023]
Abstract
The glucuronoyl esterases (GEs) that have been identified so far belong to family 15 of the carbohydrate esterases in the CAZy classification system and are presumed to target ester bonds between lignin alcohols and (4-O-methyl-)d-glucuronic acid residues of xylan. Few GEs have been cloned, expressed and characterised to date. Characterisation has been done on a variety of synthetic substrates; however, the number of commercially available substrates is very limited. We identified novel putative GEs from a wide taxonomic range of fungi and expressed the enzymes originating from Acremonium alcalophilum and Wolfiporia cocos as well as the previously described PcGE1 from Phanerochaete chrysosporium. All three fungal GEs were active on the commercially available compounds benzyl glucuronic acid (BnGlcA), allyl glucuronic acid (allylGlcA) and to a lower degree on methyl glucuronic acid (MeGlcA). The enzymes showed pH stability over a wide pH range and tolerated 6-h incubations of up to 50 °C. Kinetic parameters were determined for BnGlcA. This study shows the suitability of the commercially available model compounds BnGlcA, MeGlcA and allylGlcA in GE activity screening and characterisation experiments. We enriched the spectrum of characterised GEs with two new members of a relatively young enzyme family. Due to its biotechnological significance, this family deserves to be more extensively studied. The presented enzymes are promising candidates as auxiliary enzymes to improve saccharification of plant biomass.
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Affiliation(s)
- Silvia Hüttner
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.,Wallenberg Wood Science Center, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Sylvia Klaubauf
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.,Wallenberg Wood Science Center, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Ronald P de Vries
- Fungal Physiology, CBS-KNAW Fungal Biodiversity Centre & Fungal Molecular Physiology, Utrecht University, 3584 CT, Utrecht, The Netherlands
| | - Lisbeth Olsson
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden. .,Wallenberg Wood Science Center, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
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47
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Immobilization of indigenous holocellulase on iron oxide (Fe 2 O 3 ) nanoparticles enhanced hydrolysis of alkali pretreated paddy straw. Int J Biol Macromol 2017; 96:538-549. [DOI: 10.1016/j.ijbiomac.2016.11.109] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/26/2016] [Accepted: 11/28/2016] [Indexed: 11/19/2022]
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48
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Thomas L, Ram H, Singh VP. Evolutionary Relationships and Taxa-Specific Conserved Signature Indels Among Cellulases of Archaea, Bacteria, and Eukarya. J Comput Biol 2017; 24:1029-1042. [PMID: 28177649 DOI: 10.1089/cmb.2016.0161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The cellulases from different cellulolytic organisms have evolutionary relationships, which range from single-celled prokaryotes to the complex eukaryotes of the living world. This in silico analysis revealed the presence of a conserved cellulase domain along with evolutionary relationships among cellulases from several species of Archaea, Bacteria, and Eukarya. The amino acid sequences of cellulases from Archaea and Bacteria showed closer identity with their domain or phylum members that provided insights into convergent and divergent evolution of cellulases from other enzymes with different substrate specificities. Evolutionary relatedness was also observed in phylogenetic trees among a number of cellulase sequences of diverse taxa. In cellulases, propensity for alanine, glycine, leucine, serine, and threonine was high, but low for cysteine, histidine, and methionine. Catalytic aspartic acid had a higher propensity than glutamic acid, and both were involved in regular expression patterns. Characteristic group and multigroup-specific conserved signature indels located in the catalytic domains of cellulases were observed that further clarified evolutionary relationships. These indels can be distinctive molecular tools for understanding phylogeny and identification of unknown cellulolytic species of common evolutionary descent in different environments.
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Affiliation(s)
- Lebin Thomas
- Applied Microbiology and Biotechnology Laboratory, Department of Botany, University of Delhi , Delhi, India
| | - Hari Ram
- Applied Microbiology and Biotechnology Laboratory, Department of Botany, University of Delhi , Delhi, India
| | - Ved Pal Singh
- Applied Microbiology and Biotechnology Laboratory, Department of Botany, University of Delhi , Delhi, India
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49
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Miao Y, Li P, Li G, Liu D, Druzhinina IS, Kubicek CP, Shen Q, Zhang R. Two degradation strategies for overcoming the recalcitrance of natural lignocellulosic xylan by polysaccharides-binding GH10 and GH11 xylanases of filamentous fungi. Environ Microbiol 2017; 19:1054-1064. [PMID: 27878934 DOI: 10.1111/1462-2920.13614] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 10/23/2016] [Accepted: 11/16/2016] [Indexed: 01/08/2023]
Abstract
The recalcitrance of lignocellulose forms a strong barrier for the bioconversion of lignocellulosic biomass in chemical or biofuel industries. Filamentous fungi are major plant biomass decomposer, and capable of forming all the required enzymes. Here, they characterized the GH10 and GH11 endo-xylanases and a CE1 acetyl-xylan esterase (Axe1) from a superior biomass-degrading strain, Aspergillus fumigatus Z5, and examined how they interact in xylan degradation. Cellulose-binding (CBM1) domain inhibited GH10 xylanase activities for pure xylan, but afforded them an ability to hydrolyze washed corncob particles (WCCP). CBM1-containing GH10 xylanases also showed synergism with CBM1-containing Axe1 in WCCP hydrolysis, and this synergy was strictly dependent on the presence of their CBM1 domains. In contrast, GH11 xylanases had no CBM1, but still could bind xylan and hydrolyzed WCCP; however, no synergism displayed with Axe1. GH10 xylanases and GH11 xylanases showed a pronounced synergism in WCCP hydrolysis, which was dependent on the presence of the CBM1 in GH10 xylanases and absence from GH11 xylanases. They exhibit different mechanisms to bind to cellulose and xylan, and act in synergy when these two structures are intact. These findings will be helpful for the further development of highly efficient enzyme mixtures for lignocellulosic biomass conversion.
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Affiliation(s)
- Youzhi Miao
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Pan Li
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Guangqi Li
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Dongyang Liu
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Irina S Druzhinina
- Research Area Biochemical Technology, TU Wien, Gumpendorferstrasse 1a, Vienna, A1060, Austria
| | - Christian P Kubicek
- Research Area Biochemical Technology, TU Wien, Gumpendorferstrasse 1a, Vienna, A1060, Austria
| | - Qirong Shen
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Ruifu Zhang
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.,Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China
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Rizk M, Antranikian G, Elleuche S. Influence of Linker Length Variations on the Biomass-Degrading Performance of Heat-Active Enzyme Chimeras. Mol Biotechnol 2016; 58:268-79. [PMID: 26921187 DOI: 10.1007/s12033-016-9925-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Plant cell walls are composed of complex polysaccharides such as cellulose and hemicellulose. In order to efficiently hydrolyze cellulose, the synergistic action of several cellulases is required. Some anaerobic cellulolytic bacteria form multienzyme complexes, namely cellulosomes, while other microorganisms produce a portfolio of diverse enzymes that work in synergistic fashion. Molecular biological methods can mimic such effects through the generation of artificial bi- or multifunctional fusion enzymes. Endoglucanase and β-glucosidase from extremely thermophilic anaerobic bacteria Fervidobacterium gondwanense and Fervidobacterium islandicum, respectively, were fused end-to-end in an approach to optimize polysaccharide degradation. Both enzymes are optimally active at 90 °C and pH 6.0-7.0 representing excellent candidates for fusion experiments. The direct linkage of both enzymes led to an increased activity toward the substrate specific for β-glucosidase, but to a decreased activity of endoglucanase. However, these enzyme chimeras were superior over 1:1 mixtures of individual enzymes, because combined activities resulted in a higher final product yield. Therefore, such fusion enzymes exhibit promising features for application in industrial bioethanol production processes.
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Affiliation(s)
- Mazen Rizk
- Institute of Technical Microbiology, Hamburg University of Technology (TUHH), Kasernenstr. 12, 21073, Hamburg, Germany
| | - Garabed Antranikian
- Institute of Technical Microbiology, Hamburg University of Technology (TUHH), Kasernenstr. 12, 21073, Hamburg, Germany
| | - Skander Elleuche
- Institute of Technical Microbiology, Hamburg University of Technology (TUHH), Kasernenstr. 12, 21073, Hamburg, Germany.
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