1
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Charoenwongpaiboon T, Charoenwongphaibun C, Wangpaiboon K, Panpetch P, Wanichacheva N, Pichyangkura R. Endo- and exo-levanases from Bacillus subtilis HM7: Catalytic components, synergistic cooperation, and application in fructooligosaccharide synthesis. Int J Biol Macromol 2024; 271:132508. [PMID: 38782321 DOI: 10.1016/j.ijbiomac.2024.132508] [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: 01/01/2024] [Revised: 04/28/2024] [Accepted: 05/17/2024] [Indexed: 05/25/2024]
Abstract
Levan-type fructooligosaccharides (LFOS) exhibit significant biological activities and selectively promote the growth of certain beneficial bacteria. Levanase is an important enzyme for LFOS production. In this study, two isoforms of levanases, exo- and endo-type depolymerizing enzymes, from Bacillus subtilis HM7 isolated from Dynastes hercules larvae excrement were cloned, expressed, and characterized. The synergistic effect on the levan hydrolysis and kinetic properties of both isoforms were evaluated, indicating their cooperation in levan metabolism, where the endo-levanase catalyzes a rate-limiting step. In addition, homology models and molecular dynamics simulations revealed the key amino residues of the enzymes for levan binding and catalysis. It was found that both isoforms possessed distinct binding residues in the active sites, suggesting the importance of the specificity of the enzymes. Finally, we demonstrated the potential of endo-type levanase in LFOS synthesis using a one-pot reaction with levansucrase. Overall, this study fills the knowledge gap in understanding levanase's mechanism, making an important contribution to the fields of food science and biotechnology.
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Affiliation(s)
| | - Chonnipha Charoenwongphaibun
- Division of Chemistry, Department of Physical and Material Sciences, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen Campus, Kamphaeng Sean, Nakhon Pathom 73140, Thailand
| | - Karan Wangpaiboon
- Center of Excellence in Structural and Computational Biology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Pawinee Panpetch
- Center of Excellence in Structural and Computational Biology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Nantanit Wanichacheva
- Department of Chemistry, Faculty of Science, Silpakorn University, Nakhon Pathom 73000, Thailand
| | - Rath Pichyangkura
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
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2
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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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3
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Leadbeater DR, Bruce NC. Functional characterisation of a new halotolerant seawater active glycoside hydrolase family 6 cellobiohydrolase from a salt marsh. Sci Rep 2024; 14:3205. [PMID: 38332324 PMCID: PMC10853513 DOI: 10.1038/s41598-024-53886-4] [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: 10/18/2023] [Accepted: 02/06/2024] [Indexed: 02/10/2024] Open
Abstract
Realising a fully circular bioeconomy requires the valorisation of lignocellulosic biomass. Cellulose is the most attractive component of lignocellulose but depolymerisation is inefficient, expensive and resource intensive requiring substantial volumes of potable water. Seawater is an attractive prospective replacement, however seawater tolerant enzymes are required for the development of seawater-based biorefineries. Here, we report a halophilic cellobiohydrolase SMECel6A, identified and isolated from a salt marsh meta-exo-proteome dataset with high sequence divergence to previously characterised cellobiohydrolases. SMECel6A contains a glycoside hydrolase family 6 (GH6) domain and a carbohydrate binding module family 2 (CBM2) domain. Characterisation of recombinant SMECel6A revealed SMECel6A to be active upon crystalline and amorphous cellulose. Mono- and oligosaccharide product profiles revealed cellobiose as the major hydrolysis product confirming SMECel6A as a cellobiohydrolase. We show SMECel6A to be halophilic with optimal activity achieved in 0.5X seawater displaying 80.6 ± 6.93% activity in 1 × seawater. Structural predictions revealed similarity to a characterised halophilic cellobiohydrolase despite sharing only 57% sequence identity. Sequential thermocycling revealed SMECel6A had the ability to partially reversibly denature exclusively in seawater retaining significant activity. Our study confirms that salt marsh ecosystems harbour enzymes with attractive traits with biotechnological potential for implementation in ionic solution based bioprocessing systems.
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Affiliation(s)
- Daniel R Leadbeater
- Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York, YO10 5DD, UK.
| | - Neil C Bruce
- Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York, YO10 5DD, UK.
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4
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Nousi A, Molina GA, Schiano-di-Cola C, Sørensen TH, Borch K, Pedersen JN, Westh P, Marie R. Impact of Synergy Partner Cel7B on Cel7A Binding Rates: Insights from Single-Molecule Data. J Phys Chem B 2024; 128:635-647. [PMID: 38227769 PMCID: PMC10824242 DOI: 10.1021/acs.jpcb.3c05697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 01/02/2024] [Accepted: 01/05/2024] [Indexed: 01/18/2024]
Abstract
Enzymatic degradation of cellulosic biomass is a well-established route for the sustainable production of biofuels, chemicals, and materials. A strategy employed by nature and industry to achieve an efficient degradation of cellulose is that cellobiohydrolases (or exocellulases), such as Cel7A, work synergistically with endoglucanases, such as Cel7B, to achieve the complete degradation of cellulose. However, a complete mechanistic understanding of this exo-endo synergy is still lacking. Here, we used single-molecule fluorescence microscopy to quantify the binding kinetics of Cel7A on cellulose when it is acting alone on the cellulose fibrils and in the presence of its synergy partner, the endoglucanase Cel7B. To this end, we used a fluorescently tagged Cel7A and studied its binding in the presence of the unlabeled Cel7B. This provided the single-molecule data necessary for the estimation of the rate constants of association kON and dissociation kOFF of Cel7A for the substrate. We show that the presence of Cel7B does not impact the dissociation rate constant, kOFF. But, the association rate of Cel7A decreases by a factor of 2 when Cel7B is present at a molar proportion of 10:1. This ratio has previously been shown to lead to synergy. This decrease in association rate is observed in a wide range of total enzyme concentrations, from sub nM to μM concentrations. This decrease in kON is consistent with the formation of cellulase clusters recently observed by others using atomic force microscopy.
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Affiliation(s)
- Aimilia Nousi
- Department
of Health Technology, Technical University
of Denmark, 2800 Kongens Lyngby, Denmark
| | - Gustavo Avelar Molina
- Department
of Biotechnology and Biomedicine, Technical
University of Denmark, 2800 Kongens Lyngby, Denmark
- The
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | | | | | - Kim Borch
- Novozymes
A/S, Krogshøjvej
36, 2880 Bagsværd, Denmark
| | - Jonas N. Pedersen
- Department
of Health Technology, Technical University
of Denmark, 2800 Kongens Lyngby, Denmark
| | - Peter Westh
- Department
of Biotechnology and Biomedicine, Technical
University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Rodolphe Marie
- Department
of Health Technology, Technical University
of Denmark, 2800 Kongens Lyngby, Denmark
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5
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Sharma R, Putera KH, Banaszak Holl MM, Garnier G, Haritos VS. Modulating the hydrophobicity of cellulose by lipase-catalyzed transesterification. Int J Biol Macromol 2024; 254:127972. [PMID: 37944725 DOI: 10.1016/j.ijbiomac.2023.127972] [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: 06/27/2023] [Revised: 08/06/2023] [Accepted: 11/06/2023] [Indexed: 11/12/2023]
Abstract
The production of hydrophobic and oil resistant cellulosic fibers usually requires severe chemical treatments and generates toxic by-products. Alternative approaches such as biocatalysis use milder conditions; lipase-catalyzed methods for grafting nanocellulose with hydrophobic ester moieties have been reported. Here, we investigate the lipase-catalyzed esterification of cellulose fibers, in native form or pretreated with 1,4-β-glucanases, and cellulose nanocrystals (CNC) in solvent-free conditions. The fibers were compared for degree of ester formation after incubation with methyl myristate and lipase at 50 °C. After washing, the grafting of fatty esters on cellulose was confirmed by ATR-FTIR and the degree of substitution determined by 13C CP/MAS NMR (from 0.04 up to DS 0.1) confirming successful esterification. Optical photothermal infrared (O-PTIR) spectroscopy showed strongly localized presence of ester moieties on cellulose. Functional properties mirrored the degree of substitution of the cellulose materials whereby cellulose esters made with glucanase-pretreatment produced the highest water contact angle of 117° ± 9 and esterified cellulose blended at 10 % w/w content in paper composites showed significant differences in hydrophobicity and lipophilicity compared to plain paper. The esterification of cellulose was completely reversed by lipase treatment in aqueous media. These ester-functionalized fibers show potential in a wide range of packaging applications.
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Affiliation(s)
- Rahul Sharma
- Bioresource Processing Research Institute of Australia, Department of Chemical and Biological Engineering, Monash University, Melbourne, Victoria 3800, Australia
| | - Kevin H Putera
- Bioresource Processing Research Institute of Australia, Department of Chemical and Biological Engineering, Monash University, Melbourne, Victoria 3800, Australia
| | - Mark M Banaszak Holl
- Bioresource Processing Research Institute of Australia, Department of Chemical and Biological Engineering, Monash University, Melbourne, Victoria 3800, Australia; Department of Mechanical and Materials Engineering, University of Alabama at Birmingham, USA
| | - Gil Garnier
- Bioresource Processing Research Institute of Australia, Department of Chemical and Biological Engineering, Monash University, Melbourne, Victoria 3800, Australia
| | - Victoria S Haritos
- Bioresource Processing Research Institute of Australia, Department of Chemical and Biological Engineering, Monash University, Melbourne, Victoria 3800, Australia.
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6
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Aggarwal S, Dorairaj S, Adlakha N. Stoichiometric balance ratio of cellobiose and gentiobiose induces cellulase production in Talaromyces cellulolyticus. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:48. [PMID: 36927685 PMCID: PMC10018878 DOI: 10.1186/s13068-023-02296-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 03/02/2023] [Indexed: 03/18/2023]
Abstract
BACKGROUND The exact mechanism by which fungal strains sense insoluble cellulose is unknown, but research points to the importance of transglycosylation products generated by fungi during cellulose breakdown. Here, we used multi-omics approach to identify the transglycosylation metabolites and determine their function in cellulase induction in a model strain, Talaromyces cellulolyticus MTCC25456. RESULTS Talaromyces sp. is a novel hypercellulolytic fungal strain. Based on genome scrutiny and biochemical analysis, we predicted the presence of cellulases on the surface of its spores. We performed metabolome analysis to show that these membrane-bound cellulases act on polysaccharides to form a mixture of disaccharides and their transglycosylated derivatives. Inevitably, a high correlation existed between metabolite data and the KEGG enrichment analysis of differentially expressed genes in the carbohydrate metabolic pathway. Analysis of the contribution of the transglycosylation product mixtures to cellulase induction revealed a 57% increase in total cellulase. Further research into the metabolites, using in vitro induction tests and response surface methodology, revealed that Talaromyces sp. produces cell wall-breaking enzymes in response to cellobiose and gentiobiose as a stimulant. Precisely, a 2.5:1 stoichiometric ratio of cellobiose to gentiobiose led to a 2.4-fold increase in cellulase synthesis. The application of the optimized inducers in cre knockout strain significantly increased the enzyme output. CONCLUSION This is the first study on the objective evaluation and enhancement of cellulase production using optimized inducers. Inducer identification and genetic engineering boosted the cellulase production in the cellulolytic fungus Talaromyces sp.
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Affiliation(s)
- Shivam Aggarwal
- Synthetic Biology and Bioprocessing Group, Regional Centre for Biotechnology, NCR-Biotech Cluster, Faridabad, India
| | - Sathish Dorairaj
- Synthetic Biology and Bioprocessing Group, Regional Centre for Biotechnology, NCR-Biotech Cluster, Faridabad, India
| | - Nidhi Adlakha
- Synthetic Biology and Bioprocessing Group, Regional Centre for Biotechnology, NCR-Biotech Cluster, Faridabad, India.
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7
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Nano-biocatalytic Systems for Cellulose de-polymerization: A Drive from Design to Applications. Top Catal 2023. [DOI: 10.1007/s11244-023-01785-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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8
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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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9
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Ramírez Brenes RG, Chaves LDS, Bojorge N, Pereira N. Endo-Exoglucanase Synergism for Cellulose Nanofibril Production Assessment and Characterization. Molecules 2023; 28:molecules28030948. [PMID: 36770616 PMCID: PMC9921176 DOI: 10.3390/molecules28030948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023] Open
Abstract
A study to produce cellulose nanofibrils (CNF) from kraft cellulose pulp was conducted using a centroid simplex mixture design. The enzyme blend contains 69% endoglucanase and 31% exoglucanase. The central composite rotational design (CCRD) optimized the CNF production process by achieving a higher crystallinity index. It thus corresponded to a solid loading of 15 g/L and an enzyme loading of 0.974. Using the Segal formula, the crystallinity index (CrI) of the CNF was determined by X-ray diffraction to be 80.87%. The average diameter of the CNF prepared by enzymatic hydrolysis was 550-600 nm, while the one produced by enzymatic hydrolysis and with ultrasonic dispersion was 250-300 nm. Finally, synergistic interactions between the enzymes involved in nanocellulose production were demonstrated, with Colby factor values greater than one.
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Affiliation(s)
- Ricardo Gonzalo Ramírez Brenes
- Department of Chemical and Petroleum Engineering, Fluminense Federal University, R. Passos da Patria 156, Niterói 24210-140, RJ, Brazil
- School of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Ilha do Fundão 21941-972, RJ, Brazil
| | - Lívia da Silva Chaves
- Department of Chemical and Petroleum Engineering, Fluminense Federal University, R. Passos da Patria 156, Niterói 24210-140, RJ, Brazil
| | - Ninoska Bojorge
- Department of Chemical and Petroleum Engineering, Fluminense Federal University, R. Passos da Patria 156, Niterói 24210-140, RJ, Brazil
- Correspondence: (N.B.); (N.P.J.)
| | - Nei Pereira
- School of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Ilha do Fundão 21941-972, RJ, Brazil
- Correspondence: (N.B.); (N.P.J.)
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10
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Duarte M, Alves VD, Correia M, Caseiro C, Ferreira LM, Romão MJ, Carvalho AL, Najmudin S, Bayer EA, Fontes CM, Bule P. Structure-function studies can improve binding affinity of cohesin-dockerin interactions for multi-protein assemblies. Int J Biol Macromol 2022; 224:55-67. [DOI: 10.1016/j.ijbiomac.2022.10.102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/28/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022]
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11
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Zajki-Zechmeister K, Eibinger M, Nidetzky B. Enzyme Synergy in Transient Clusters of Endo- and Exocellulase Enables a Multilayer Mode of Processive Depolymerization of Cellulose. ACS Catal 2022; 12:10984-10994. [PMID: 36082050 PMCID: PMC9442579 DOI: 10.1021/acscatal.2c02377] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 08/12/2022] [Indexed: 11/29/2022]
Abstract
Biological degradation of cellulosic materials relies on the molecular-mechanistic principle that internally chain-cleaving endocellulases work synergistically with chain end-cleaving exocellulases in polysaccharide chain depolymerization. How endo-exo synergy becomes effective in the deconstruction of a solid substrate that presents cellulose chains assembled into crystalline material is an open question of the mechanism, with immediate implications on the bioconversion efficiency of cellulases. Here, based on single-molecule evidence from real-time atomic force microscopy, we discover that endo- and exocellulases engage in the formation of transient clusters of typically three to four enzymes at the cellulose surface. The clusters form specifically at regular domains of crystalline cellulose microfibrils that feature molecular defects in the polysaccharide chain organization. The dynamics of cluster formation correlates with substrate degradation through a multilayer-processive mode of chain depolymerization, overall leading to the directed ablation of single microfibrils from the cellulose surface. Each multilayer-processive step involves the spatiotemporally coordinated and mechanistically concerted activity of the endo- and exocellulases in close proximity. Mechanistically, the cooperativity with the endocellulase enables the exocellulase to pass through its processive cycles ∼100-fold faster than when acting alone. Our results suggest an advanced paradigm of efficient multienzymatic degradation of structurally organized polymer materials by endo-exo synergetic chain depolymerization.
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Affiliation(s)
- Krisztina Zajki-Zechmeister
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Manuel Eibinger
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Bernd Nidetzky
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
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12
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Wang D, Kao MR, Li J, Sun P, Meng Q, Vyas A, Liang PH, Wang YS, Hsieh YSY. Novel Two-Step Process in Cellulose Depolymerization: Hematite-Mediated Photocatalysis by Lytic Polysaccharide Monooxygenase and Fenton Reaction. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:9941-9947. [PMID: 35921143 PMCID: PMC9389612 DOI: 10.1021/acs.jafc.2c02445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
To transform cellulose from biomass into fermentable sugars for biofuel production requires efficient enzymatic degradation of cellulosic feedstocks. The recently discovered family of oxidative enzymes, lytic polysaccharide monooxygenase (LPMO), has a high potential for industrial biorefinery, but its energy efficiency and scalability still have room for improvement. Hematite (α-Fe2O3) can act as a photocatalyst by providing electrons to LPMO-catalyzed reactions, is low cost, and is found abundantly on the Earth's surface. Here, we designed a composite enzymatic photocatalysis-Fenton reaction system based on nano-α-Fe2O3. The feasibility of using α-Fe2O3 nanoparticles as a composite catalyst to facilitate LPMO-catalyzed cellulose oxidative degradation in water was tested. Furthermore, a light-induced Fenton reaction was integrated to increase the liquefaction yield of cellulose. The innovative approach finalized the cellulose degradation process with a total liquefaction yield of 93%. Nevertheless, the complex chemical reactions and products involved in this system require further investigation.
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Affiliation(s)
- Damao Wang
- College
of Food Science, Southwest University, Chongqing 400715, PR China
- Division
of Glycoscience, Department of Chemistry, School of Engineering Sciences
in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Center, Stockholm SE10691, Sweden
- School
of Pharmacy, College of Pharmacy, Taiwan
Medical University, Taipei 110, Taiwan
| | - Mu-Rong Kao
- School
of Pharmacy, College of Pharmacy, Taiwan
Medical University, Taipei 110, Taiwan
| | - Jing Li
- Division
of Glycoscience, Department of Chemistry, School of Engineering Sciences
in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Center, Stockholm SE10691, Sweden
- College
of Life Sciences, Shanghai Normal University, Shanghai 220234, PR China
| | - Peicheng Sun
- Laboratory
of Food Chemistry, Wageningen University
& Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Qijun Meng
- Division
of Organic Chemistry, Department of Chemistry, School of Engineering
Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), Stockholm SE1004, Sweden
| | - Anisha Vyas
- Division
of Glycoscience, Department of Chemistry, School of Engineering Sciences
in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Center, Stockholm SE10691, Sweden
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, 8010 Graz, Austria
| | - Pi-Hui Liang
- College
of Pharmacy, National Taiwan University, Taipei 100, Taiwan
| | - Yane-Shih Wang
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Yves S. Y. Hsieh
- Division
of Glycoscience, Department of Chemistry, School of Engineering Sciences
in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Center, Stockholm SE10691, Sweden
- School
of Pharmacy, College of Pharmacy, Taiwan
Medical University, Taipei 110, Taiwan
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13
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Dorival J, Moraïs S, Labourel A, Rozycki B, Cazade PA, Dabin J, Setter-Lamed E, Mizrahi I, Thompson D, Thureau A, Bayer EA, Czjzek M. Mapping the deformability of natural and designed cellulosomes in solution. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:68. [PMID: 35725490 PMCID: PMC9210761 DOI: 10.1186/s13068-022-02165-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 06/08/2022] [Indexed: 12/02/2022]
Abstract
BACKGROUND Natural cellulosome multi-enzyme complexes, their components, and engineered 'designer cellulosomes' (DCs) promise an efficient means of breaking down cellulosic substrates into valuable biofuel products. Their broad uptake in biotechnology relies on boosting proximity-based synergy among the resident enzymes, but the modular architecture challenges structure determination and rational design. RESULTS We used small angle X-ray scattering combined with molecular modeling to study the solution structure of cellulosomal components. These include three dockerin-bearing cellulases with distinct substrate specificities, original scaffoldins from the human gut bacterium Ruminococcus champanellensis (ScaA, ScaH and ScaK) and a trivalent cohesin-bearing designer scaffoldin (Scaf20L), followed by cellulosomal complexes comprising these components, and the nonavalent fully loaded Clostridium thermocellum CipA in complex with Cel8A from the same bacterium. The size analysis of Rg and Dmax values deduced from the scattering curves and corresponding molecular models highlight their variable aspects, depending on composition, size and spatial organization of the objects in solution. CONCLUSIONS Our data quantifies variability of form and compactness of cellulosomal components in solution and confirms that this native plasticity may well be related to speciation with respect to the substrate that is targeted. By showing that scaffoldins or components display enhanced compactness compared to the free objects, we provide new routes to rationally enhance their stability and performance in their environment of action.
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Affiliation(s)
- Jonathan Dorival
- Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), Sorbonne Université, CNRS, 29680, Roscoff, Bretagne, France
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
| | - Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, 8499000, Beer-Sheva, Israel
| | - Aurore Labourel
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Bartosz Rozycki
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland
| | - Pierre-Andre Cazade
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | - Jérôme Dabin
- Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), Sorbonne Université, CNRS, 29680, Roscoff, Bretagne, France
| | - Eva Setter-Lamed
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Itzhak Mizrahi
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, 8499000, Beer-Sheva, Israel
| | - Damien Thompson
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | | | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, 8499000, Beer-Sheva, Israel
| | - Mirjam Czjzek
- Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), Sorbonne Université, CNRS, 29680, Roscoff, Bretagne, France.
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14
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Qu M, Guo X, Tian S, Yang Q, Kim M, Mun S, Noh MY, Kramer KJ, Muthukrishnan S, Arakane Y. AA15 lytic polysaccharide monooxygenase is required for efficient chitinous cuticle turnover during insect molting. Commun Biol 2022; 5:518. [PMID: 35641660 PMCID: PMC9156745 DOI: 10.1038/s42003-022-03469-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 05/10/2022] [Indexed: 11/09/2022] Open
Abstract
Microbial lytic polysaccharide monooxygenases (LPMOs) catalyze the oxidative cleavage of crystalline polysaccharides including chitin and cellulose. The discovery of a large assortment of LPMO-like proteins widely distributed in insect genomes suggests that they could be involved in assisting chitin degradation in the exoskeleton, tracheae and peritrophic matrix during development. However, the physiological functions of insect LPMO-like proteins are still undetermined. To investigate the functions of insect LPMO15 subgroup I-like proteins (LPMO15-1s), two evolutionarily distant species, Tribolium castaneum and Locusta migratoria, were chosen. Depletion by RNAi of T. castaneum TcLPMO15-1 caused molting arrest at all developmental stages, whereas depletion of the L. migratoria LmLPMO15-1, prevented only adult eclosion. In both species, LPMO15-1-deficient animals were unable to shed their exuviae and died. TEM analysis revealed failure of turnover of the chitinous cuticle, which is critical for completion of molting. Purified recombinant LPMO15-1-like protein from Ostrinia furnacalis (rOfLPMO15-1) exhibited oxidative cleavage activity and substrate preference for chitin. These results reveal the physiological importance of catalytically active LPMO15-1-like proteins from distant insect species and provide new insight into the enzymatic mechanism of cuticular chitin turnover during molting.
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Affiliation(s)
- Mingbo Qu
- School of Bioengineering, Dalian University of Technology, 116024, Dalian, China
| | - Xiaoxi Guo
- School of Bioengineering, Dalian University of Technology, 116024, Dalian, China
| | - Shuang Tian
- School of Bioengineering, Dalian University of Technology, 116024, Dalian, China
| | - Qing Yang
- School of Bioengineering, Dalian University of Technology, 116024, Dalian, China.
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, 100193, Beijing, China.
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, 518120, Shenzhen, China.
| | - Myeongjin Kim
- Department of Applied Biology, Chonnam National University, Gwangju, 61186, South Korea
| | - Seulgi Mun
- Department of Applied Biology, Chonnam National University, Gwangju, 61186, South Korea
| | - Mi Young Noh
- Department of Forest Resources, AgriBio Institute of Climate Change Management, Chonnam National University, Gwangju, 61186, South Korea
| | - Karl J Kramer
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA
| | - Subbaratnam Muthukrishnan
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA
| | - Yasuyuki Arakane
- Department of Applied Biology, Chonnam National University, Gwangju, 61186, South Korea.
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15
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Ye TJ, Huang KF, Ko TP, Wu SH. Synergic action of an inserted carbohydrate-binding module in a glycoside hydrolase family 5 endoglucanase. Acta Crystallogr D Struct Biol 2022; 78:633-646. [PMID: 35503211 PMCID: PMC9063844 DOI: 10.1107/s2059798322002601] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/07/2022] [Indexed: 11/24/2022] Open
Abstract
Most known cellulase-associated carbohydrate-binding modules (CBMs) are attached to the N- or C-terminus of the enzyme or are expressed separately and assembled into multi-enzyme complexes (for example to form cellulosomes), rather than being an insertion into the catalytic domain. Here, by solving the crystal structure, it is shown that MtGlu5 from Meiothermus taiwanensis WR-220, a GH5-family endo-β-1,4-glucanase (EC 3.2.1.4), has a bipartite architecture consisting of a Cel5A-like catalytic domain with a (β/α)8 TIM-barrel fold and an inserted CBM29-like noncatalytic domain with a β-jelly-roll fold. Deletion of the CBM significantly reduced the catalytic efficiency of MtGlu5, as determined by isothermal titration calorimetry using inactive mutants of full-length and CBM-deleted MtGlu5 proteins. Conversely, insertion of the CBM from MtGlu5 into TmCel5A from Thermotoga maritima greatly enhanced the substrate affinity of TmCel5A. Bound sugars observed between two tryptophan side chains in the catalytic domains of active full-length and CBM-deleted MtGlu5 suggest an important stacking force. The synergistic action of the catalytic domain and CBM of MtGlu5 in binding to single-chain polysaccharides was visualized by substrate modeling, in which additional surface tryptophan residues were identified in a cross-domain groove. Subsequent site-specific mutagenesis results confirmed the pivotal role of several other tryptophan residues from both domains of MtGlu5 in substrate binding. These findings reveal a way to incorporate a CBM into the catalytic domain of an existing enzyme to make a robust cellulase.
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Affiliation(s)
- Ting-Juan Ye
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
- Department of Chemistry, National Taiwan University, Taipei 115, Taiwan
| | - Kai-Fa Huang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Tzu-Ping Ko
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Shih-Hsiung Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei 115, Taiwan
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16
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Chang YP, Wee WY, Wan KW, Loh KM, Lee KC. Improvement of prebiotic activity of guava purée by-products through cellulase treatment. FOOD BIOTECHNOL 2022. [DOI: 10.1080/08905436.2021.2006063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Ying Ping Chang
- Department of Agricultural and Food Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia
| | - Wei Yik Wee
- Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia
| | - Kah Wai Wan
- Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia
| | - Kah Mun Loh
- Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia
| | - Kok Chang Lee
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia
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17
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Biochemical and Structural Analysis of a Glucose-Tolerant β-Glucosidase from the Hemicellulose-Degrading Thermoanaerobacterium saccharolyticum. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27010290. [PMID: 35011521 PMCID: PMC8746653 DOI: 10.3390/molecules27010290] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/30/2021] [Accepted: 12/08/2021] [Indexed: 01/09/2023]
Abstract
β-Glucosidases (Bgls) convert cellobiose and other soluble cello-oligomers into glucose and play important roles in fundamental biological processes, providing energy sources in living organisms. Bgls are essential terminal enzymes of cellulose degradation systems and attractive targets for lignocellulose-based biotechnological applications. Characterization of novel Bgls is important for broadening our knowledge of this enzyme class and can provide insights into its further applications. In this study, we report the biochemical and structural analysis of a Bgl from the hemicellulose-degrading thermophilic anaerobe Thermoanaerobacterium saccharolyticum (TsaBgl). TsaBgl exhibited its maximum hydrolase activity on p-nitrophenyl-β-d-glucopyranoside at pH 6.0 and 55 °C. The crystal structure of TsaBgl showed a single (β/α)8 TIM-barrel fold, and a β8-α14 loop, which is located around the substrate-binding pocket entrance, showing a unique conformation compared with other structurally known Bgls. A Tris molecule inhibited enzyme activity and was bound to the active site of TsaBgl coordinated by the catalytic residues Glu163 (proton donor) and Glu351 (nucleophile). Titration experiments showed that TsaBgl belongs to the glucose-tolerant Bgl family. The gatekeeper site of TsaBgl is similar to those of other glucose-tolerant Bgls, whereas Trp323 and Leu170, which are involved in glucose tolerance, show a unique configuration. Our results therefore improve our knowledge about the Tris-mediated inhibition and glucose tolerance of Bgl family members, which is essential for their industrial application.
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18
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Kuroda K, Ueda M. Simultaneous Display of Multiple Kinds of Enzymes on the Yeast Cell Surface for Multistep Reactions. Methods Mol Biol 2022; 2491:627-641. [PMID: 35482207 DOI: 10.1007/978-1-0716-2285-8_26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The yeast surface display system is a valuable platform for constructing cells with novel functions for various applications and high-throughput screening of protein or peptide libraries containing random mutations. Among the host microorganisms used for surface display, yeast is the most suitable microorganism for surface engineering owing to its eukaryotic features. In yeast, proper folding and glycosylation of expressed eukaryotic proteins can be performed. Furthermore, in this system, multiple kinds of proteins can be simultaneously displayed on the cell surface. This allows for a synergistic effect between the displayed enzymes, leading to an efficient multistep reaction. Alternatively, the ratio of the enzymes to be displayed can be controlled by the co-culture of surface-engineered yeasts displaying a single kind of enzyme. Therefore, yeast surface display systems have been applied to the construction of various whole-cell biocatalysts. Here, we describe methods for the simultaneous display of multiple kinds of proteins on the yeast cell surface.
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Affiliation(s)
- Kouichi Kuroda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
| | - Mitsuyoshi Ueda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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19
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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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20
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Adsorption of enzymes with hydrolytic activity on polyethylene terephthalate. Enzyme Microb Technol 2021; 152:109937. [PMID: 34749019 DOI: 10.1016/j.enzmictec.2021.109937] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 11/24/2022]
Abstract
Polyethylene terephthalate (PET) degrading enzymes have recently obtained an increasing interest as a means to decompose plastic waste. Here, we have studied the binding of three PET hydrolases on a suspended PET powder under conditions of both enzyme- and substrate excess. A Langmuir isotherm described the binding process reasonably and revealed a prominent affinity for the PET substrate, with dissociation constants consistently below 150 nM. The saturated substrate coverage approximately corresponded to a monolayer on the PET surface for all three enzymes. No distinct contributions from specific ligand binding in the active site could be identified, which points towards adsorption predominantly driven by non-specific interactions in contrast to enzymes naturally evolved for the breakdown of insoluble polymers. However, we observed a correlation between the progression of enzymatic hydrolysis and increased binding capacity, probably due to surface modifications of the PET polymer over time. Our results provide functional insight, suggesting that rational design should target the specific ligand interaction in the active site rather than the already high, general adsorption capacity of these enzymes.
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21
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Defining the Frontiers of Synergism between Cellulolytic Enzymes for Improved Hydrolysis of Lignocellulosic Feedstocks. Catalysts 2021. [DOI: 10.3390/catal11111343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Lignocellulose has economic potential as a bio-resource for the production of value-added products (VAPs) and biofuels. The commercialization of biofuels and VAPs requires efficient enzyme cocktail activities that can lower their costs. However, the basis of the synergism between enzymes that compose cellulolytic enzyme cocktails for depolymerizing lignocellulose is not understood. This review aims to address the degree of synergism (DS) thresholds between the cellulolytic enzymes and how this can be used in the formulation of effective cellulolytic enzyme cocktails. DS is a powerful tool that distinguishes between enzymes’ synergism and anti-synergism during the hydrolysis of biomass. It has been established that cellulases, or cellulases and lytic polysaccharide monooxygenases (LPMOs), always synergize during cellulose hydrolysis. However, recent evidence suggests that this is not always the case, as synergism depends on the specific mechanism of action of each enzyme in the combination. Additionally, expansins, nonenzymatic proteins responsible for loosening cell wall fibers, seem to also synergize with cellulases during biomass depolymerization. This review highlighted the following four key factors linked to DS: (1) a DS threshold at which the enzymes synergize and produce a higher product yield than their theoretical sum, (2) a DS threshold at which the enzymes display synergism, but not a higher product yield, (3) a DS threshold at which enzymes do not synergize, and (4) a DS threshold that displays anti-synergy. This review deconvolutes the DS concept for cellulolytic enzymes, to postulate an experimental design approach for achieving higher synergism and cellulose conversion yields.
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22
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Zajki-Zechmeister K, Kaira GS, Eibinger M, Seelich K, Nidetzky B. Processive Enzymes Kept on a Leash: How Cellulase Activity in Multienzyme Complexes Directs Nanoscale Deconstruction of Cellulose. ACS Catal 2021; 11:13530-13542. [PMID: 34777910 PMCID: PMC8576811 DOI: 10.1021/acscatal.1c03465] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/11/2021] [Indexed: 12/15/2022]
Abstract
Biological deconstruction of polymer materials gains efficiency from the spatiotemporally coordinated action of enzymes with synergetic function in polymer chain depolymerization. To perpetuate enzyme synergy on a solid substrate undergoing deconstruction, the overall attack must alternate between focusing the individual enzymes locally and dissipating them again to other surface sites. Natural cellulases working as multienzyme complexes assembled on a scaffold protein (the cellulosome) maximize the effect of local concentration yet restrain the dispersion of individual enzymes. Here, with evidence from real-time atomic force microscopy to track nanoscale deconstruction of single cellulose fibers, we show that the cellulosome forces the fiber degradation into the transversal direction, to produce smaller fragments from multiple local attacks ("cuts"). Noncomplexed enzymes, as in fungal cellulases or obtained by dissociating the cellulosome, release the confining force so that fiber degradation proceeds laterally, observed as directed ablation of surface fibrils and leading to whole fiber "thinning". Processive cellulases that are enabled to freely disperse evoke the lateral degradation and determine its efficiency. Our results suggest that among natural cellulases, the dispersed enzymes are more generally and globally effective in depolymerization, while the cellulosome represents a specialized, fiber-fragmenting machinery.
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Affiliation(s)
- Krisztina Zajki-Zechmeister
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Gaurav Singh Kaira
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
| | - Manuel Eibinger
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Klara Seelich
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Bernd Nidetzky
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
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23
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Sukumaran RK, Christopher M, Kooloth-Valappil P, Sreeja-Raju A, Mathew RM, Sankar M, Puthiyamadam A, Adarsh VP, Aswathi A, Rebinro V, Abraham A, Pandey A. Addressing challenges in production of cellulases for biomass hydrolysis: Targeted interventions into the genetics of cellulase producing fungi. BIORESOURCE TECHNOLOGY 2021; 329:124746. [PMID: 33610429 DOI: 10.1016/j.biortech.2021.124746] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
Lignocellulosic materials are the favoured feedstock for biorefineries due to their abundant availability and non-completion with food. Biobased technologies for refining these materials are limited mainly by the cost of biomass hydrolyzing enzymes, typically sourced from filamentous fungi. Therefore, considerable efforts have been directed at improving the quantity and quality of secreted lignocellulose degrading enzymes from fungi in order to attain overall economic viability. Process improvements and media engineering probably have reached their thresholds and further production enhancements require modifying the fungal metabolism to improve production and secretion of these enzymes. This review focusses on the types and mechanisms of action of known fungal biomass degrading enzymes, our current understanding of the genetic control exerted on their expression, and possible routes for intervention, especially on modulating catabolite repression, transcriptional regulators, signal transduction, secretion pathways etc., in order to improve enzyme productivity, activity and stability.
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Affiliation(s)
- Rajeev K Sukumaran
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India.
| | - Meera Christopher
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Prajeesh Kooloth-Valappil
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - AthiraRaj Sreeja-Raju
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Reshma M Mathew
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Meena Sankar
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Anoop Puthiyamadam
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
| | - Velayudhanpillai-Prasannakumari Adarsh
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
| | - Aswathi Aswathi
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Valan Rebinro
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
| | - Amith Abraham
- Department of Chemical Engineering, Hanyang University, Seoul, Republic of Korea
| | - Ashok Pandey
- Centre for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow, India
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24
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Li X. Plant cell wall chemistry: implications for ruminant utilisation. JOURNAL OF APPLIED ANIMAL NUTRITION 2021. [DOI: 10.3920/jaan2020.0017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ruminants have adapted to cope with bulky, fibrous forage diets by accommodating a large, diverse microbial population in the reticulo-rumen. Ruminants are dependent on forages as their main sources of energy and other nutrients. Forages are comprised of a complex matrix of cellulose, hemicellulose, protein, minerals and phenolic compounds (including lignin and tannins) with various linkages; many of which are poorly defined. The composition and characteristics of polysaccharides vary greatly among forages and plant cell walls. Plant cell walls are linked and packed together in tight configurations to resist degradation, and hence their nutritional value to animals varies considerably, depending on composition, structure and degradability. An understanding of the inter-relationship between the chemical composition and the degradation of plant cell walls by rumen microorganisms is of major economic importance to ruminant production. Increasing the efficiency of fibre degradation in the rumen has been the subject of extensive research for many decades. This review summarises current knowledge of forage chemistry in order to develop strategies to increase efficiency of forage utilisation by ruminants.
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Affiliation(s)
- X. Li
- The University of Queensland, School of Agriculture and Food Sciences, Gatton, Qld 4343, Australia
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25
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Anuganti M, Fu H, Ekatan S, Kumar CV, Lin Y. Kinetic Study on Enzymatic Hydrolysis of Cellulose in an Open, Inhibition-Free System. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5180-5192. [PMID: 33872034 DOI: 10.1021/acs.langmuir.1c00115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Due to the complexity of cellulases and the requirement of enzyme adsorption on cellulose prior to reactions, it is difficult to evaluate their reaction with a general mechanistic scheme. Nevertheless, it is of great interest to come up with an approximate analytic description of a valid model for the purpose of developing an intuitive understanding of these complex enzyme systems. Herein, we used the surface plasmonic resonance method to monitor the action of a cellobiohydrolase by itself, as well as its mixture with a synergetic endoglucanase, on the surface of a regenerated model cellulose film, under continuous flow conditions. We found a phenomenological approach by taking advantage of the long steady state of cellulose hydrolysis in the open, inhibition-free system. This provided a direct and reliable way to analyze the adsorption and reaction processes with a minimum number of fitting parameters. We investigated a generalized Langmuir-Michaelis-Menten model to describe a full set of kinetic results across a range of enzyme concentrations, compositions, and temperatures. The overall form of the equations describing the pseudo-steady-state kinetics of the flow-system shares some interesting similarities with the Michaelis-Menten equation. The use of familiar Michaelis-Menten parameters in the analysis provides a unifying framework to study cellulase kinetics. The strategy may provide a shortcut for approaching a quantitative while intuitive understanding of enzymatic degradation of cellulose from top to bottom. The open system approach and the kinetic analysis should be applicable to a variety of cellulases and reaction systems to accelerate the progress in the field.
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Affiliation(s)
- Murali Anuganti
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Hailin Fu
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Stephen Ekatan
- Polymer Program, Institute of Material Sciences, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Challa V Kumar
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Yao Lin
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Polymer Program, Institute of Material Sciences, University of Connecticut, Storrs, Connecticut 06269, United States
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Müller M, Calvert M, Hottmann I, Kluj RM, Teufel T, Balbuchta K, Engelbrecht A, Selim KA, Xu Q, Borisova M, Titz A, Mayer C. The exo-β-N-acetylmuramidase NamZ from Bacillus subtilis is the founding member of a family of exo-lytic peptidoglycan hexosaminidases. J Biol Chem 2021; 296:100519. [PMID: 33684445 PMCID: PMC8054146 DOI: 10.1016/j.jbc.2021.100519] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/27/2021] [Accepted: 03/04/2021] [Indexed: 11/11/2022] Open
Abstract
Endo-β-N-acetylmuramidases, commonly known as lysozymes, are well-characterized antimicrobial enzymes that catalyze an endo-lytic cleavage of peptidoglycan; i.e., they hydrolyze the β-1,4-glycosidic bonds connecting N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc). In contrast, little is known about exo-β-N-acetylmuramidases, which catalyze an exo-lytic cleavage of β-1,4-MurNAc entities from the non-reducing ends of peptidoglycan chains. Such an enzyme was identified earlier in the bacterium Bacillus subtilis, but the corresponding gene has remained unknown so far. We now report that ybbC of B. subtilis, renamed namZ, encodes the reported exo-β-N-acetylmuramidase. A ΔnamZ mutant accumulated specific cell wall fragments and showed growth defects under starvation conditions, indicating a role of NamZ in cell wall turnover and recycling. Recombinant NamZ protein specifically hydrolyzed the artificial substrate para-nitrophenyl β-MurNAc and the peptidoglycan-derived disaccharide MurNAc-β-1,4-GlcNAc. Together with the exo-β-N-acetylglucosaminidase NagZ and the exo-muramoyl-l-alanine amidase AmiE, NamZ degraded intact peptidoglycan by sequential hydrolysis from the non-reducing ends. A structure model of NamZ, built on the basis of two crystal structures of putative orthologs from Bacteroides fragilis, revealed a two-domain structure including a Rossmann-fold-like domain that constitutes a unique glycosidase fold. Thus, NamZ, a member of the DUF1343 protein family of unknown function, is now classified as the founding member of a new family of glycosidases (CAZy GH171; www.cazy.org/GH171.html). NamZ-like peptidoglycan hexosaminidases are mainly present in the phylum Bacteroidetes and less frequently found in individual genomes within Firmicutes (Bacilli, Clostridia), Actinobacteria, and γ-proteobacteria.
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Affiliation(s)
- Maraike Müller
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Matthew Calvert
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Isabel Hottmann
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Robert Maria Kluj
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Tim Teufel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Katja Balbuchta
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alicia Engelbrecht
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Khaled A Selim
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany; Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Center, Giza, Egypt
| | - Qingping Xu
- GM/CA @ APS, Argonne National Laboratory, Lemont, Illinois, USA
| | - Marina Borisova
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alexander Titz
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Christoph Mayer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany.
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Revisiting the Phenomenon of Cellulase Action: Not All Endo- and Exo-Cellulase Interactions Are Synergistic. Catalysts 2021. [DOI: 10.3390/catal11020170] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The conventional endo–exo synergism model has extensively been supported in literature, which is based on the perception that endoglucanases (EGs) expose or create accessible sites on the cellulose chain to facilitate the action of processive cellobiohydrolases (CBHs). However, there is a lack of information on why some bacterial and fungal CBHs and EGs do not exhibit synergism. Therefore, the present study evaluated and compared the synergistic relationships between cellulases from different microbial sources and provided insights into how different GH families govern synergism. The results showed that CmixA2 (a mixture of TlCel7A and CtCel5A) displayed the highest effect with BaCel5A (degree of synergy for reducing sugars and glucose of 1.47 and 1.41, respectively) in a protein mass ratio of 75–25%. No synergism was detected between CmixB1/B2 (as well as CmixC1/C2) and any of the EGs, and the combinations did not improve the overall cellulose hydrolysis. These findings further support the hypothesis that “not all endo-to exo-cellulase interactions are synergistic”, and that the extent of synergism is dependent on the composition of cellulase systems from various sources and their compatibility in the cellulase cocktail. This method of screening for maximal compatibility between exo- and endo-cellulases constitutes a critical step towards the design of improved synergistic cellulose-degrading cocktails for industrial-scale biomass degradation.
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Zou G, Bao D, Wang Y, Zhou S, Xiao M, Yang Z, Wang Y, Zhou Z. Alleviating product inhibition of Trichoderma reesei cellulase complex with a product-activated mushroom endoglucanase. BIORESOURCE TECHNOLOGY 2021; 319:124119. [PMID: 32957048 DOI: 10.1016/j.biortech.2020.124119] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
Product inhibition of cellulase is a challenging issue in industrial processes. Here, we introduced a product-activated mushroom cellulase, PaCel3A from Polyporus arcularius, into Trichoderma reesei. The filter paper activity, carboxymethyl cellulase activity, and saccharification efficiency (substrate: pretreated rice straw, PRS) of transformants increased significantly with this enzyme (by 18.4-26.8%, 13.8-22.8%, and 17.0%, respectively). A mutant of PaCel3A, PaCel3AM, obtained based on B-factor analysis, saturated mutagenesis, and residual activity assay, showed improved thermostability. The PRS saccharification efficiency using the cellulase complex from T. reesei transformants overexpressing pacel3am increased by 56.4%-63.0%. In addition, the T. reesei cellulase complex obtained by adding the purified recombinant PaCel3AM from T. reesei (rCel3aM-tr) to hydrolyze PRS resulted in increased reducing sugar yields at all sampling points, outperforming the cellulase complexes without rCel3aM-tr. These results suggest that introducing product-activated cellulase genes is a simple and feasible method to alleviate the product inhibition of cellulase.
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Affiliation(s)
- Gen Zou
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China; CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
| | - Dapeng Bao
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China.
| | - Ying Wang
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China
| | - Sichi Zhou
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China
| | - Meili Xiao
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
| | - Zhanshan Yang
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China
| | - Yinmei Wang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
| | - Zhihua Zhou
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
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29
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Nemmaru B, Ramirez N, Farino CJ, Yarbrough JM, Kravchenko N, Chundawat SPS. Reduced type-A carbohydrate-binding module interactions to cellulose I leads to improved endocellulase activity. Biotechnol Bioeng 2020; 118:1141-1151. [PMID: 33245142 DOI: 10.1002/bit.27637] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/12/2020] [Accepted: 11/15/2020] [Indexed: 12/24/2022]
Abstract
Dissociation of nonproductively bound cellulolytic enzymes from cellulose is hypothesized to be a key rate-limiting factor impeding cost-effective biomass conversion to fermentable sugars. However, the role of carbohydrate-binding modules (CBMs) in enabling nonproductive enzyme binding is not well understood. Here, we examine the subtle interplay of CBM binding and cellulose hydrolysis activity for three models type-A CBMs (Families 1, 3a, and 64) tethered to multifunctional endoglucanase (CelE) on two distinct cellulose allomorphs (i.e., cellulose I and III). We generated a small library of mutant CBMs with varying cellulose affinity, as determined by equilibrium binding assays, followed by monitoring cellulose hydrolysis activity of CelE-CBM fusion constructs. Finally, kinetic binding assays using quartz crystal microbalance with dissipation were employed to measure CBM adsorption and desorption rate constants k on and k off , respectively, towards nanocrystalline cellulose derived from both allomorphs. Overall, our results indicate that reduced CBM equilibrium binding affinity towards cellulose I alone, resulting from increased desorption rates ( k off ) and reduced effective adsorption rates ( nk on ), is correlated to overall improved endocellulase activity. Future studies could employ similar approaches to unravel the role of CBMs in nonproductive enzyme binding and develop improved cellulolytic enzymes for industrial applications.
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Affiliation(s)
| | - Nicholas Ramirez
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Cindy J Farino
- Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - John M Yarbrough
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Nicholas Kravchenko
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Shishir P S Chundawat
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
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30
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A steady-state approach for inhibition of heterogeneous enzyme reactions. Biochem J 2020; 477:1971-1982. [PMID: 32391552 DOI: 10.1042/bcj20200083] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/07/2020] [Accepted: 05/11/2020] [Indexed: 02/02/2023]
Abstract
The kinetic theory of enzymes that modify insoluble substrates is still underdeveloped, despite the prevalence of this type of reaction both in vivo and industrial applications. Here, we present a steady-state kinetic approach to investigate inhibition occurring at the solid-liquid interface. We propose to conduct experiments under enzyme excess (E0 ≫ S0), i.e. the opposite limit compared with the conventional Michaelis-Menten framework. This inverse condition is practical for insoluble substrates and elucidates how the inhibitor reduces enzyme activity through binding to the substrate. We claim that this type of inhibition is common for interfacial enzyme reactions because substrate accessibility is low, and we show that it can be analyzed by experiments and rate equations that are analogous to the conventional approach, except that the roles of enzyme and substrate have been swapped. To illustrate the approach, we investigated the major cellulases from Trichoderma reesei (Cel6A and Cel7A) acting on insoluble cellulose. As model inhibitors, we used catalytically inactive variants of Cel6A and Cel7A. We made so-called inverse Michaelis-Menten curves at different concentrations of inhibitors and found that a new rate equation accounted well for the data. In most cases, we found a mixed type of surface-site inhibition mechanism, and this probably reflected that the inhibitor both competed with the enzyme for the productive binding-sites (competitive inhibition) and hampered the processive movement on the surface (uncompetitive inhibition). These results give new insights into the complex interplay of Cel7A and Cel6A on cellulose and the approach may be applicable to other heterogeneous enzyme reactions.
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31
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Durham EK, Sastry SK. Moderate Electric Field Treatment Enhances Enzymatic Hydrolysis of Cellulose at Below-Optimal Temperatures. Enzyme Microb Technol 2020; 142:109678. [PMID: 33220866 DOI: 10.1016/j.enzmictec.2020.109678] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/16/2020] [Accepted: 09/29/2020] [Indexed: 11/25/2022]
Abstract
Saccharification of cellulosic biomass for the fermentation of transportation fuels faces several challenges. Cellulose is highly stable, and even with enzymatic assistance, decomposition of cellulose is slow. Additionally, the enzymes are expensive and sensitive to thermal and mechanical inactivation. In this work, we studied the effects of moderate electric field (MEF, in the range from 1 to 1000 V per cm) treatments on the effectiveness of enzymatic saccharification. MEF treatments were applied to determine their effects on enzyme activity. We considered the effects of field strength, frequency, application regime and temperature. It was found that the enzyme responded to alterations in the frequency of the waveform, with 50 to 60 Hz maximizing the effects of the field, although the effects of field strength and application regime were more significant. It was found that the electric field could have a positive, negative, or negligible effect depending on the field strength. Most notably, when MEF treatments were applied over a range of temperatures, it was found that MEF treatment significantly improved enzyme activity at lower temperatures, leading to the observation that MEF treatment imitates a temperature increase. Calculations simulating the electrophoretic motion of the enzymes verified that the magnitude of motion associated with the MEF treatments was qualitatively similar to the change in molecular motion associated with temperature increases.
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Affiliation(s)
- Emily K Durham
- Department of Food, Agricultural and Biological Engineering, The Ohio State University, 590 Woody Hayes Drive, Columbus, OH, 43210, USA.
| | - Sudhir K Sastry
- Department of Food, Agricultural and Biological Engineering, The Ohio State University, 590 Woody Hayes Drive, Columbus, OH, 43210, USA.
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32
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Song T, Wang X, Wu M, Zhao K, Wang X, Chu Y, Lin J. Agarase cocktail from agar polysaccharide utilization loci converts homogenized Gelidium amansii into neoagarooligosaccharides. Food Chem 2020; 352:128685. [PMID: 33691998 DOI: 10.1016/j.foodchem.2020.128685] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 11/17/2022]
Abstract
Neoagarooligosaccharides (NAOs) are drawing more and more attention because of their numerous bioactivities, yet limited number of agarases impedes NAOs production from red algae. In this study, predicted agar polysaccharide utilization loci (agar-PUL) were firstly used as inventory for agarase. 6 agarases were identified from agar-PULs and two of them were successfully expressed and analyzed. Then enzyme cocktail (GH16-1:GH16-2:Aga50D = 2:1:1) was proved to have highest synergistic effect. Finally homogenization was applied to G. amansii and proved to be an efficient way to release agar from tissues. When liquid-to-solid ratio was 9 g/150 mL, homogenization time was 20 min, and enzyme cocktail loading was 150 U/150 mL, maximum NAOs production (90.2 mg per 9 g wet G. amansii) could be achieved. Enzyme supported one-step process (ESOP) proposed in study is environment-friendly, time saving, cost saving and none-destructive, therefore has a potential industrial application in red algae utilization.
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Affiliation(s)
- Tao Song
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610106, PR China
| | - Xiaotao Wang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610106, PR China
| | - Minghao Wu
- School of Pharmacy, Chengdu Medical College, 610500 Chengdu, PR China
| | - Kelei Zhao
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610106, PR China
| | - Xinrong Wang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610106, PR China
| | - Yiwen Chu
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610106, PR China
| | - Jiafu Lin
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610106, PR China.
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Qu M, Watanabe-Nakayama T, Sun S, Umeda K, Guo X, Liu Y, Ando T, Yang Q. High-Speed Atomic Force Microscopy Reveals Factors Affecting the Processivity of Chitinases during Interfacial Enzymatic Hydrolysis of Crystalline Chitin. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02751] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mingbo Qu
- School of Bioengineering, Dalian University of Technology, No. 2, Linggong Road, Dalian 116024, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Beijing 100193, China
| | | | - Shaopeng Sun
- School of Bioengineering, Dalian University of Technology, No. 2, Linggong Road, Dalian 116024, China
| | - Kenichi Umeda
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Xiaoxi Guo
- School of Bioengineering, Dalian University of Technology, No. 2, Linggong Road, Dalian 116024, China
| | - Yuansheng Liu
- School of Bioengineering, Dalian University of Technology, No. 2, Linggong Road, Dalian 116024, China
| | - Toshio Ando
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Qing Yang
- School of Bioengineering, Dalian University of Technology, No. 2, Linggong Road, Dalian 116024, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Beijing 100193, China
- Guangdong Laboratory for Lingnan Modern Agriculture (Shenzhen Branch), Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, No. 7 Pengfei Road, Shenzhen 518120, China
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34
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Kuntothom T, Cairns JK. Expression and characterization of TbCel12A, a thermophilic endoglucanase with potential in biomass hydrolysis. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2020. [DOI: 10.1016/j.bcab.2020.101835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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35
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Østby H, Hansen LD, Horn SJ, Eijsink VGH, Várnai A. Enzymatic processing of lignocellulosic biomass: principles, recent advances and perspectives. J Ind Microbiol Biotechnol 2020; 47:623-657. [PMID: 32840713 PMCID: PMC7658087 DOI: 10.1007/s10295-020-02301-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023]
Abstract
Efficient saccharification of lignocellulosic biomass requires concerted development of a pretreatment method, an enzyme cocktail and an enzymatic process, all of which are adapted to the feedstock. Recent years have shown great progress in most aspects of the overall process. In particular, increased insights into the contributions of a wide variety of cellulolytic and hemicellulolytic enzymes have improved the enzymatic processing step and brought down costs. Here, we review major pretreatment technologies and different enzyme process setups and present an in-depth discussion of the various enzyme types that are currently in use. We pay ample attention to the role of the recently discovered lytic polysaccharide monooxygenases (LPMOs), which have led to renewed interest in the role of redox enzyme systems in lignocellulose processing. Better understanding of the interplay between the various enzyme types, as they may occur in a commercial enzyme cocktail, is likely key to further process improvements.
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Affiliation(s)
- Heidi Østby
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Line Degn Hansen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Svein J Horn
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway.
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Hefferon K, Cantero-Tubilla B, Badar U, Wilson DW. Plant-Based Cellulase Assay Systems as Alternatives for Synthetic Substrates. Appl Biochem Biotechnol 2020; 192:1318-1330. [PMID: 32734581 DOI: 10.1007/s12010-020-03395-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/16/2020] [Indexed: 11/25/2022]
Abstract
Dissociative enzymes such as cellulases are greatly desired for a variety of applications in the food, fuel, and fiber industries. Cellulases and other cell wall-degrading enzymes are currently being engineered with improved traits for application in the breakdown of lignocellulosic biomass. Biochemical assays using these "designer" enzymes have traditionally been carried out using synthetic substrates such as crystalline bacterial microcellulose (BMCC). However, the use of synthetic substrates may not reflect the actual action of these cellulases on real plant biomass. We examined the potential of suspension cell walls from several plant species as possible alternatives for synthetic cellulose substrates. Suspension cells grow synchronously; hence, their cell walls are more uniform than those derived from mature plants. This work will help to establish a new assay system that is more genuine than using synthetic substrates. In addition to this, we have demonstrated that it is feasible to produce cellulases inexpensively and at high concentrations and activities in plants using a recombinant plant virus expression system. Our long-term goals are to use this system to develop tailored cocktails of cellulases that have been engineered to function optimally for specific tasks (i.e., the conversion of biomass into biofuel or the enhancement of nutrients available in livestock feed). The broad impact would be to provide a facile and economic system for generating industrial enzymes that offer green solutions to valorize biomass in industrialized communities and specifically in developing countries.
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Affiliation(s)
- Kathleen Hefferon
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA.
| | - Borja Cantero-Tubilla
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14850, USA
| | - Uzma Badar
- Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - David W Wilson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA
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37
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Gabiatti Junior C, Dal Magro L, Graebin NG, Rodrigues E, Rodrigues RC, Prentice C. Combination of Celluclast and Viscozyme improves enzymatic hydrolysis of residual cellulose casings: process optimization and scale-up. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2020. [DOI: 10.1007/s43153-020-00050-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Enzymatic Hydrolysis of Softwood Derived Paper Sludge by an In Vitro Recombinant Cellulase Cocktail for the Production of Fermentable Sugars. Catalysts 2020. [DOI: 10.3390/catal10070775] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Paper sludge is an attractive biomass feedstock for bioconversion to ethanol due to its low cost and the lack of pretreatment required for its bioprocessing. This study assessed the use of a recombinant cellulase cocktail (mono-components: S. cerevisiae-derived PcBGL1B (BGL), TeCel7A (CBHI), ClCel6A (CBHII) and TrCel5A (EGII) mono-component cellulase enzymes) for the efficient saccharification of softwood-derived paper sludge to produce fermentable sugars. The paper sludge mainly contained 74.3% moisture and 89.7% (per dry mass (DM)) glucan with a crystallinity index of 91.5%. The optimal protein ratio for paper sludge hydrolysis was observed at 9.4: 30.2: 30.2: 30.2% for BGL: CBHI: CBHII: EGII. At a protein loading of 7.5 mg/g DW paper sludge, the yield from hydrolysis was approximately 80%, based on glucan, with scanning electron microscopy micrographs indicating a significant alteration in the microfibril size (length reduced from ≥ 2 mm to 93 µm) of the paper sludge. The paper sludge hydrolysis potential of the Opt CelMix (formulated cellulase cocktail) was similar to the commercial Cellic CTec2® and Celluclast® 1.5 L cellulase preparations and better than Viscozyme® L. Low enzyme loadings (15 mg/g paper sludge) of the Opt CelMix and solid loadings ranging between 1 to 10% (w/v) rendered over 80% glucan conversion. The high glucose yields attained on the paper sludge by the low enzyme loading of the Opt CelMix demonstrated the value of enzyme cocktail optimisation on specific substrates for efficient cellulose conversion to fermentable sugars.
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Tokin R, Ipsen JØ, Westh P, Johansen KS. The synergy between LPMOs and cellulases in enzymatic saccharification of cellulose is both enzyme- and substrate-dependent. Biotechnol Lett 2020; 42:1975-1984. [DOI: 10.1007/s10529-020-02922-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 05/20/2020] [Indexed: 11/28/2022]
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A Novel Cellobiohydrolase I (CBHI) from Penicillium digitatum: Production, Purification, and Characterization. Appl Biochem Biotechnol 2020; 192:257-282. [PMID: 32378080 DOI: 10.1007/s12010-020-03307-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 03/12/2020] [Indexed: 01/09/2023]
Abstract
A new cellulase producer strain of Penicillium digitatum (RV 06) was previously obtained from rotten maize grains. This work aim was to optimize the production and characterize this microorganism produced cellulase. A CMCase maximum production (1.6 U/mL) was obtained in stationary liquid culture, with an initial pH of 5.0, at 25 °C, with 1% lactose as carbon source, and cultured for 5 days. The produced enzyme was purified by ammonium sulfate precipitation and exclusion chromatography. The purified enzyme optimal temperature and pH were 60 °C and 5.2, respectively. The experimental Tm of thermal inactivation was 63.68 °C, and full activity was recovered after incubation of 7 h at 50 °C. The purified 74 kDa CMCase presented KM for CMC of 11.2 mg/mL, Vmax of 0.13 μmol/min, kcat of 52 s-1, and kcat/KM of 4.7 (mg/mL)-1 s-1. The purified enzyme had a high specificity for CMC and p-nitrophenyl cellobioside and released glucose and cellobiose as final products of the CMC hydrolysis. The enzyme trypsin digestion produced peptides whose masses were obtained by MALDI-TOF/TOF mass spectrometry, which was also used to obtain two peptide sequences. These peptide sequences and the mass peak profile retrieved a CBHI within the annotated genome of P. digitatum PD1. Sequence alignments and phylogenetic analysis confirmed this enzyme as a CBHI of the glycoside hydrolase family 7. The P. digitatum PD1 protein in silico structural model revealed a coil and β-conformation predominance, which was confirmed by circular dichroism of the P. digitatum RV 06 purified enzyme.
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Claes A, Deparis Q, Foulquié-Moreno MR, Thevelein JM. Simultaneous secretion of seven lignocellulolytic enzymes by an industrial second-generation yeast strain enables efficient ethanol production from multiple polymeric substrates. Metab Eng 2020; 59:131-141. [DOI: 10.1016/j.ymben.2020.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/01/2020] [Accepted: 02/18/2020] [Indexed: 01/22/2023]
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Contreras F, Pramanik S, M. Rozhkova A, N. Zorov I, Korotkova O, P. Sinitsyn A, Schwaneberg U, D. Davari M. Engineering Robust Cellulases for Tailored Lignocellulosic Degradation Cocktails. Int J Mol Sci 2020; 21:E1589. [PMID: 32111065 PMCID: PMC7084875 DOI: 10.3390/ijms21051589] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/11/2022] Open
Abstract
Lignocellulosic biomass is a most promising feedstock in the production of second-generation biofuels. Efficient degradation of lignocellulosic biomass requires a synergistic action of several cellulases and hemicellulases. Cellulases depolymerize cellulose, the main polymer of the lignocellulosic biomass, to its building blocks. The production of cellulase cocktails has been widely explored, however, there are still some main challenges that enzymes need to overcome in order to develop a sustainable production of bioethanol. The main challenges include low activity, product inhibition, and the need to perform fine-tuning of a cellulase cocktail for each type of biomass. Protein engineering and directed evolution are powerful technologies to improve enzyme properties such as increased activity, decreased product inhibition, increased thermal stability, improved performance in non-conventional media, and pH stability, which will lead to a production of more efficient cocktails. In this review, we focus on recent advances in cellulase cocktail production, its current challenges, protein engineering as an efficient strategy to engineer cellulases, and our view on future prospects in the generation of tailored cellulases for biofuel production.
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Affiliation(s)
- Francisca Contreras
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Subrata Pramanik
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Aleksandra M. Rozhkova
- Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences, 119071 Moscow, Russia
- Department of Chemistry, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Ivan N. Zorov
- Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences, 119071 Moscow, Russia
- Department of Chemistry, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Olga Korotkova
- Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences, 119071 Moscow, Russia
| | - Arkady P. Sinitsyn
- Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences, 119071 Moscow, Russia
- Department of Chemistry, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Ulrich Schwaneberg
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany
| | - Mehdi D. Davari
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
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Røjel N, Kari J, Sørensen TH, Badino SF, Morth JP, Schaller K, Cavaleiro AM, Borch K, Westh P. Substrate binding in the processive cellulase Cel7A: Transition state of complexation and roles of conserved tryptophan residues. J Biol Chem 2020; 295:1454-1463. [PMID: 31848226 PMCID: PMC7008363 DOI: 10.1074/jbc.ra119.011420] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/17/2019] [Indexed: 11/06/2022] Open
Abstract
Cellobiohydrolases effectively degrade cellulose and are of biotechnological interest because they can convert lignocellulosic biomass to fermentable sugars. Here, we implemented a fluorescence-based method for real-time measurements of complexation and decomplexation of the processive cellulase Cel7A and its insoluble substrate, cellulose. The method enabled detailed kinetic and thermodynamic analyses of ligand binding in a heterogeneous system. We studied WT Cel7A and several variants in which one or two of four highly conserved Trp residues in the binding tunnel had been replaced with Ala. WT Cel7A had on/off-rate constants of 1 × 105 m-1 s-1 and 5 × 10-3 s-1, respectively, reflecting the slow dynamics of a solid, polymeric ligand. Especially the off-rate constant was many orders of magnitude lower than typical values for small, soluble ligands. Binding rate and strength both were typically lower for the Trp variants, but effects of the substitutions were moderate and sometimes negligible. Hence, we propose that lowering the activation barrier for complexation is not a major driving force for the high conservation of the Trp residues. Using so-called Φ-factor analysis, we analyzed the kinetic and thermodynamic results for the variants. The results of this analysis suggested a transition state for complexation and decomplexation in which the reducing end of the ligand is close to the tunnel entrance (near Trp-40), whereas the rest of the binding tunnel is empty. We propose that this structure defines the highest free-energy barrier of the overall catalytic cycle and hence governs the turnover rate of this industrially important enzyme.
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Affiliation(s)
- Nanna Røjel
- Institut for Naturvidenskab og Miljo, Roskilde University, DK-4000 Roskilde, Denmark
| | - Jeppe Kari
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | | | - Silke F Badino
- Institut for Naturvidenskab og Miljo, Roskilde University, DK-4000 Roskilde, Denmark
| | - J Preben Morth
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Kay Schaller
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | | | - Kim Borch
- Novozymes A/S, DK-2800 Kgs. Lyngby Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
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Visootsat A, Nakamura A, Vignon P, Watanabe H, Uchihashi T, Iino R. Single-molecule imaging analysis reveals the mechanism of a high-catalytic-activity mutant of chitinase A from Serratia marcescens. J Biol Chem 2020; 295:1915-1925. [PMID: 31924658 PMCID: PMC7029130 DOI: 10.1074/jbc.ra119.012078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/03/2020] [Indexed: 12/17/2022] Open
Abstract
Chitin degradation is important for biomass conversion and has potential applications for agriculture, biotechnology, and the pharmaceutical industry. Chitinase A from the Gram-negative bacterium Serratia marcescens (SmChiA) is a processive enzyme that hydrolyzes crystalline chitin as it moves linearly along the substrate surface. In a previous study, the catalytic activity of SmChiA against crystalline chitin was found to increase after the tryptophan substitution of two phenylalanine residues (F232W and F396W), located at the entrance and exit of the substrate binding cleft of the catalytic domain, respectively. However, the mechanism underlying this high catalytic activity remains elusive. In this study, single-molecule fluorescence imaging and high-speed atomic force microscopy were applied to understand the mechanism of this high-catalytic-activity mutant. A reaction scheme including processive catalysis was used to reproduce the properties of SmChiA WT and F232W/F396W, in which all of the kinetic parameters were experimentally determined. High activity of F232W/F396W mutant was caused by a high processivity and a low dissociation rate constant after productive binding. The turnover numbers for both WT and F232W/F396W, determined by the biochemical analysis, were well-replicated using the kinetic parameters obtained from single-molecule imaging analysis, indicating the validity of the reaction scheme. Furthermore, alignment of amino acid sequences of 258 SmChiA-like proteins revealed that tryptophan, not phenylalanine, is the predominant amino acid at the corresponding positions (Phe-232 and Phe-396 for SmChiA). Our study will be helpful for understanding the kinetic mechanisms and further improvement of crystalline chitin hydrolytic activity of SmChiA mutants.
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Affiliation(s)
- Akasit Visootsat
- Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa 240-0193, Japan; Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Akihiko Nakamura
- Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa 240-0193, Japan; Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Paul Vignon
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan; Chimie ParisTech, Paris 75231, France
| | - Hiroki Watanabe
- Department of Physics, Nagoya University, Nagoya, Aichi 464-8601, Japan; Exploratory Research Center on Life and Living Systems (ExCELLS), National Institute of Natural Science, Okazaki, Aichi 444-8787, Japan
| | - Takayuki Uchihashi
- Department of Physics, Nagoya University, Nagoya, Aichi 464-8601, Japan; Exploratory Research Center on Life and Living Systems (ExCELLS), National Institute of Natural Science, Okazaki, Aichi 444-8787, Japan
| | - Ryota Iino
- Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa 240-0193, Japan; Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.
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Inokuma K, Kurono H, den Haan R, van Zyl WH, Hasunuma T, Kondo A. Novel strategy for anchorage position control of GPI-attached proteins in the yeast cell wall using different GPI-anchoring domains. Metab Eng 2019; 57:110-117. [PMID: 31715252 DOI: 10.1016/j.ymben.2019.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/15/2019] [Accepted: 11/08/2019] [Indexed: 01/16/2023]
Abstract
The yeast cell surface provides space to display functional proteins. Heterologous proteins can be covalently anchored to the yeast cell wall by fusing them with the anchoring domain of glycosylphosphatidylinositol (GPI)-anchored cell wall proteins (GPI-CWPs). In the yeast cell-surface display system, the anchorage position of the target protein in the cell wall is an important factor that maximizes the capabilities of engineered yeast cells because the yeast cell wall consists of a 100- to 200-nm-thick microfibrillar array of glucan chains. However, knowledge is limited regarding the anchorage position of GPI-attached proteins in the yeast cell wall. Here, we report a comparative study on the effect of GPI-anchoring domain-heterologous protein fusions on yeast cell wall localization. GPI-anchoring domains derived from well-characterized GPI-CWPs, namely Sed1p and Sag1p, were used for the cell-surface display of heterologous proteins in the yeast Saccharomyces cerevisiae. Immunoelectron-microscopic analysis of enhanced green fluorescent protein (eGFP)-displaying cells revealed that the anchorage position of the GPI-attached protein in the cell wall could be controlled by changing the fused anchoring domain. eGFP fused with the Sed1-anchoring domain predominantly localized to the external surface of the cell wall, whereas the anchorage position of eGFP fused with the Sag1-anchoring domain was mainly inside the cell wall. We also demonstrate the application of the anchorage position control technique to improve the cellulolytic ability of cellulase-displaying yeast. The ethanol titer during the simultaneous saccharification and fermentation of hydrothermally-processed rice straw was improved by 30% after repositioning the exo- and endo-cellulases using Sed1- and Sag1-anchor domains. This novel anchorage position control strategy will enable the efficient utilization of the cell wall space in various fields of yeast cell-surface display technology.
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Affiliation(s)
- Kentaro Inokuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Hiroki Kurono
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Riaan den Haan
- Department of Biotechnology, University of the Western Cape, Bellville, 7530, South Africa
| | - Willem Heber van Zyl
- Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan; Engineering Biology Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.
| | - Akihiko Kondo
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan; Engineering Biology Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan; Biomass Engineering Program, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
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Abstract
Cellulase enzymes deconstruct recalcitrant cellulose into soluble sugars, making them a biocatalyst of biotechnological interest for use in the nascent lignocellulosic bioeconomy. Cellobiohydrolases (CBHs) are cellulases capable of liberating many sugar molecules in a processive manner without dissociating from the substrate. Within the complete processive cycle of CBHs, dissociation from the cellulose substrate is rate limiting, but the molecular mechanism of this step is unknown. Here, we present a direct comparison of potential molecular mechanisms for dissociation via Hamiltonian replica exchange molecular dynamics of the model fungal CBH, Trichoderma reesei Cel7A. Computational rate estimates indicate that stepwise cellulose dethreading from the binding tunnel is 4 orders of magnitude faster than a clamshell mechanism, in which the substrate-enclosing loops open and release the substrate without reversing. We also present the crystal structure of a disulfide variant that covalently links substrate-enclosing loops on either side of the substrate-binding tunnel, which constitutes a CBH that can only dissociate via stepwise dethreading. Biochemical measurements indicate that this variant has a dissociation rate constant essentially equivalent to the wild type, implying that dethreading is likely the predominant mechanism for dissociation.
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Hefferon KL, Cantero‐Tubilla B, Brady J, Wilson D. Aromatic residues surrounding the active site tunnel of TfCel48A influence activity, processivity, and synergistic interactions with other cellulases. Biotechnol Bioeng 2019; 116:2463-2472. [DOI: 10.1002/bit.27086] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/29/2019] [Accepted: 06/02/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Kathleen L. Hefferon
- Department of Cellular and Molecular GeneticsCornell University Ithaca New York
- Department of Food Science and TechnologyCornell University Ithaca New York
| | - Borja Cantero‐Tubilla
- Robert Frederick Smith School of Chemical and Biomolecular EngineeringCornell University Ithaca New York
| | - John Brady
- Department of Food Science and TechnologyCornell University Ithaca New York
| | - David Wilson
- Department of Cellular and Molecular GeneticsCornell University Ithaca New York
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48
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Arnal G, Stogios PJ, Asohan J, Attia MA, Skarina T, Viborg AH, Henrissat B, Savchenko A, Brumer H. Substrate specificity, regiospecificity, and processivity in glycoside hydrolase family 74. J Biol Chem 2019; 294:13233-13247. [PMID: 31324716 DOI: 10.1074/jbc.ra119.009861] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/16/2019] [Indexed: 12/11/2022] Open
Abstract
Glycoside hydrolase family 74 (GH74) is a historically important family of endo-β-glucanases. On the basis of early reports of detectable activity on cellulose and soluble cellulose derivatives, GH74 was originally considered to be a "cellulase" family, although more recent studies have generally indicated a high specificity toward the ubiquitous plant cell wall matrix glycan xyloglucan. Previous studies have indicated that GH74 xyloglucanases differ in backbone cleavage regiospecificities and can adopt three distinct hydrolytic modes of action: exo, endo-dissociative, and endo-processive. To improve functional predictions within GH74, here we coupled in-depth biochemical characterization of 17 recombinant proteins with structural biology-based investigations in the context of a comprehensive molecular phylogeny, including all previously characterized family members. Elucidation of four new GH74 tertiary structures, as well as one distantly related dual seven-bladed β-propeller protein from a marine bacterium, highlighted key structure-function relationships along protein evolutionary trajectories. We could define five phylogenetic groups, which delineated the mode of action and the regiospecificity of GH74 members. At the extremes, a major group of enzymes diverged to hydrolyze the backbone of xyloglucan nonspecifically with a dissociative mode of action and relaxed backbone regiospecificity. In contrast, a sister group of GH74 enzymes has evolved a large hydrophobic platform comprising 10 subsites, which facilitates processivity. Overall, the findings of our study refine our understanding of catalysis in GH74, providing a framework for future experimentation as well as for bioinformatics predictions of sequences emerging from (meta)genomic studies.
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Affiliation(s)
- Gregory Arnal
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Peter J Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Jathavan Asohan
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Mohamed A Attia
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada; Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Tatiana Skarina
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Alexander Holm Viborg
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, Aix-Marseille University, 13007 Marseille, France; INRA, USC1408 Architecture et Fonction des Macromolécules Biologiques (AFMB), 13007 Marseille, France
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada; Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta T2N 4N1, Canada.
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada; Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada; Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
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Sun X, Li Y, Tian Z, Qian Y, Zhang H, Wang L. A novel thermostable chitinolytic machinery of Streptomyces sp. F-3 consisting of chitinases with different action modes. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:136. [PMID: 31171937 PMCID: PMC6545677 DOI: 10.1186/s13068-019-1472-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND The biodegradation of chitin is an important part of the carbon and nitrogen cycles in nature. Speeding up the biotransformation of chitin substrates can not only reduce pollution, but also produce high value-added products. However, this process is strictly regulated by the catalytic efficiency of the chitinolytic machinery. Therefore, it is necessary to study the mode of action and compound mechanisms of different chitin-degrading enzymes in depth to improve the catalytic efficiency of the chitinolytic machinery. RESULTS The thermophilic bacterium Streptomyces sp. F-3 showed comparatively high chitin degradation activities. To elucidate the mechanism underlying chitin hydrolysis, six chitin degradation-related enzymes were identified in the extracellular proteome of Streptomyces sp. F-3, including three chitinases (SsChi18A, SsChi18B, and SsChi18C) from the GH18 family, one GH19 chitinase (SsChi19A), one GH20 β-N-acetylhexosaminidase (SsGH20A), and one lytic polysaccharide monooxygenase (SsLPMO10A) from the AA10 family. All were upregulated by chitin. The heterologously expressed hydrolases could withstand temperatures up to 70 °C and were stable at pH values of 4 to 11. Biochemical analyses displayed that these chitin degradation-related enzymes had different functions and thus showed synergistic effects during chitin degradation. Furthermore, based on structural bioinformatics data, we speculated that the different action modes among the three GH18 chitinases may be caused by loop differences in their active site architectures. Among them, SsChi18A is probably processive and mainly acts on polysaccharides, while SsChi18B and SsChi18C are likely endo-non-processive and displayed higher activity on the degradation of chitin oligosaccharides. In addition, proteomic data and synergy experiments also indicated the importance of SsLPMO10A, which could promote the activities of the hydrolases and increase the monosaccharide content in the reaction system, respectively. CONCLUSIONS In this article, the chitinolytic machinery of a thermophilic Streptomyces species was studied to explore the structural basis for the synergistic actions of chitinases from different GH18 subfamilies. The elucidation of the degradation mechanisms of these thermophilic chitinases will lay a theoretical foundation for the efficient industrialized transformation of natural chitin.
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Affiliation(s)
- Xiaomeng Sun
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Yingjie Li
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Zhennan Tian
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Yuanchao Qian
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Huaiqiang Zhang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
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50
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Carbohydrate binding modules enhance cellulose enzymatic hydrolysis by increasing access of cellulases to the substrate. Carbohydr Polym 2019; 211:57-68. [DOI: 10.1016/j.carbpol.2019.01.108] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/24/2019] [Accepted: 01/30/2019] [Indexed: 11/22/2022]
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