1
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Windels A, Franceus J, Pleiss J, Desmet T. CANDy: Automated analysis of domain architectures in carbohydrate-active enzymes. PLoS One 2024; 19:e0306410. [PMID: 38990885 PMCID: PMC11238990 DOI: 10.1371/journal.pone.0306410] [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: 04/18/2024] [Accepted: 06/17/2024] [Indexed: 07/13/2024] Open
Abstract
Carbohydrate-active enzymes (CAZymes) can be found in all domains of life and play a crucial role in metabolic and physiological processes. CAZymes often possess a modular structure, comprising not only catalytic domains but also associated domains such as carbohydrate-binding modules (CBMs) and linker domains. By exploring the modular diversity of CAZy families, catalysts with novel properties can be discovered and further insight in their biological functions and evolutionary relationships can be obtained. Here we present the carbohydrate-active enzyme domain analysis tool (CANDy), an assembly of several novel scripts, tools and databases that allows users to analyze the domain architecture of all protein sequences in a given CAZy family. CANDy's usability is shown on glycoside hydrolase family 48, a small yet underexplored family containing multi-domain enzymes. Our analysis reveals the existence of 35 distinct domain assemblies, including eight known architectures, with the remaining assemblies awaiting characterization. Moreover, we substantiate the occurrence of horizontal gene transfer from prokaryotes to insect orthologs and provide evidence for the subsequent removal of auxiliary domains, likely through a gene fission event. CANDy is available at https://github.com/PyEED/CANDy.
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Affiliation(s)
- Alex Windels
- Department of Biotechnology, Centre for Synthetic Biology (CSB), Ghent University, Ghent, Belgium
| | - Jorick Franceus
- Department of Biotechnology, Centre for Synthetic Biology (CSB), Ghent University, Ghent, Belgium
| | - Jürgen Pleiss
- Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, Stuttgart, Germany
| | - Tom Desmet
- Department of Biotechnology, Centre for Synthetic Biology (CSB), Ghent University, Ghent, Belgium
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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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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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4
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Kuch NJ, Kutschke ME, Parker A, Bingman CA, Fox BG. Contribution of calcium ligands in substrate binding and product release in the Acetovibrio thermocellus glycoside hydrolase family 9 cellulase CelR. J Biol Chem 2023; 299:104655. [PMID: 36990218 PMCID: PMC10149213 DOI: 10.1016/j.jbc.2023.104655] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
Enzymatic deconstruction of lignocellulosic biomass is crucial to establishment of the renewable biofuel and bioproduct economy. Better understanding of these enzymes, including their catalytic and binding domains, and other features offer potential avenues for improvement. Glycoside hydrolase family 9 (GH9) enzymes are attractive targets because they have members that exhibit exo- and endo-cellulolytic activity, processivity of reaction, and thermostability. This study examines a GH9 from Acetovibrio thermocellus ATCC 27405, AtCelR containing a catalytic domain and a carbohydrate binding module (CBM3c). Crystal structures of the enzyme without substrate, bound to cellohexaose (substrate) or cellobiose (product), show the positioning of ligands to calcium and adjacent residues in the catalytic domain that may contribute to substrate binding and facilitate product release. We also investigated the properties of the enzyme engineered to contain an additional carbohydrate binding module (CBM3a). Relative to the catalytic domain alone, CBM3a gave improved binding for Avicel (a crystalline form of cellulose), and catalytic efficiency (kcat/KM) was improved 40× with both CBM3c and CBM3a present. However, because of the molecular weight added by CBM3a, the specific activity of the engineered enzyme was not increased relative to the native construct consisting of only the catalytic and CBM3c domains. This work provides new insight into a potential role of the conserved calcium in the catalytic domain and identifies contributions and limitations of domain engineering for AtCelR and perhaps other GH9 enzymes.
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Affiliation(s)
- Nathaniel J Kuch
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Mark E Kutschke
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Alex Parker
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; Dane County Youth Apprenticeship Program, Dane County School Consortium, Monona, Wisconsin, USA
| | - Craig A Bingman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; Collaborative Crystallography Core, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Brian G Fox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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5
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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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6
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Zhai R, Hu J, Jin M. Towards efficient enzymatic saccharification of pretreated lignocellulose: Enzyme inhibition by lignin-derived phenolics and recent trends in mitigation strategies. Biotechnol Adv 2022; 61:108044. [PMID: 36152893 DOI: 10.1016/j.biotechadv.2022.108044] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/24/2022] [Accepted: 09/19/2022] [Indexed: 01/01/2023]
Abstract
Lignocellulosic biorefinery based on its sugar-platform has been considered as an efficient strategy to replace fossil fuel-based refinery. In the bioconversion process, pretreatment is an essential step to firstly open up lignocellulose cell wall structure and enhance the accessibility of carbohydrates to hydrolytic enzymes. However, various lignin and/or carbohydrates degradation products (e.g. phenolics, 5-hydroxymethylfurfural, furfural) also generated during pretreatment, which severely inhibit the following enzymatic hydrolysis and the downstream fermentation process. Among them, the lignin derived phenolics have been considered as the most inhibitory compounds and their inhibitory effects are highly dependent on the source of biomass and the type of pretreatment strategy. Although liquid-solid separation and subsequent washing can remove the lignin derived phenolics and other inhibitors, this is undesirable in the realistic industrial application where the whole slurry of pretreated biomass need to be directly used in the hydrolysis process. This review summarizes the phenolics formation mechanism for various commonly applied pretreatment methods and discusses the key factors that affect the inhibitory effect of phenolics on cellulose hydrolysis. In addition, the recent achievements on the rational design of inhibition mitigation strategies to boost cellulose hydrolysis for sugar-platform biorefinery are also introduced. This review also provides guidance for rational design detoxification strategies to facilitate whole slurry hydrolysis which helps to realize the industrialization of lignocellulose biorefinery.
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Affiliation(s)
- Rui Zhai
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Jianguang Hu
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary T2N 1N4, Canada
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China.
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7
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Schaller KS, Molina GA, Kari J, Schiano-di-Cola C, Sørensen TH, Borch K, Peters GH, Westh P. Virtual Bioprospecting of Interfacial Enzymes: Relating Sequence and Kinetics. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kay S. Schaller
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
- Department of Chemistry, Technical University of Denmark, Kemitorvet, DK-2800 Kgs. Lyngby, Denmark
| | - Gustavo Avelar Molina
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
| | - Jeppe Kari
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
- Department of Science and Environment, Roskilde University, Universitetsvej 1, DK-4000 Roskilde, Denmark
| | - Corinna Schiano-di-Cola
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
| | | | - Kim Borch
- Novozymes A/S, Biologiens Vej 2, DK-2800 Kgs. Lyngby, Denmark
| | - Günther H.J. Peters
- Department of Chemistry, Technical University of Denmark, Kemitorvet, DK-2800 Kgs. Lyngby, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
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8
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Bhardwaj N, Kumar B, Agrawal K, Verma P. Current perspective on production and applications of microbial cellulases: a review. BIORESOUR BIOPROCESS 2021; 8:95. [PMID: 38650192 PMCID: PMC10992179 DOI: 10.1186/s40643-021-00447-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/21/2021] [Indexed: 12/27/2022] Open
Abstract
The potential of cellulolytic enzymes has been widely studied and explored for bioconversion processes and plays a key role in various industrial applications. Cellulase, a key enzyme for cellulose-rich waste feedstock-based biorefinery, has increasing demand in various industries, e.g., paper and pulp, juice clarification, etc. Also, there has been constant progress in developing new strategies to enhance its production, such as the application of waste feedstock as the substrate for the production of individual or enzyme cocktails, process parameters control, and genetic manipulations for enzyme production with enhanced yield, efficiency, and specificity. Further, an insight into immobilization techniques has also been presented for improved reusability of cellulase, a critical factor that controls the cost of the enzyme at an industrial scale. In addition, the review also gives an insight into the status of the significant application of cellulase in the industrial sector, with its techno-economic analysis for future applications. The present review gives a complete overview of current perspectives on the production of microbial cellulases as a promising tool to develop a sustainable and greener concept for industrial applications.
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Affiliation(s)
- Nisha Bhardwaj
- Bioprocess and Bioenergy Laboratory, Department of Microbiology, Central University of Rajasthan, NH-8, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
- Department of Chemical Engineering, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga, Mumbai, Maharashtra, 400019, India
| | - Bikash Kumar
- Bioprocess and Bioenergy Laboratory, Department of Microbiology, Central University of Rajasthan, NH-8, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
| | - Komal Agrawal
- Bioprocess and Bioenergy Laboratory, Department of Microbiology, Central University of Rajasthan, NH-8, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
| | - Pradeep Verma
- Bioprocess and Bioenergy Laboratory, Department of Microbiology, Central University of Rajasthan, NH-8, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India.
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9
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Kari J, Molina GA, Schaller KS, Schiano-di-Cola C, Christensen SJ, Badino SF, Sørensen TH, Røjel NS, Keller MB, Sørensen NR, Kolaczkowski B, Olsen JP, Krogh KBRM, Jensen K, Cavaleiro AM, Peters GHJ, Spodsberg N, Borch K, Westh P. Physical constraints and functional plasticity of cellulases. Nat Commun 2021; 12:3847. [PMID: 34158485 PMCID: PMC8219668 DOI: 10.1038/s41467-021-24075-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 05/17/2021] [Indexed: 11/16/2022] Open
Abstract
Enzyme reactions, both in Nature and technical applications, commonly occur at the interface of immiscible phases. Nevertheless, stringent descriptions of interfacial enzyme catalysis remain sparse, and this is partly due to a shortage of coherent experimental data to guide and assess such work. In this work, we produced and kinetically characterized 83 cellulases, which revealed a conspicuous linear free energy relationship (LFER) between the substrate binding strength and the activation barrier. The scaling occurred despite the investigated enzymes being structurally and mechanistically diverse. We suggest that the scaling reflects basic physical restrictions of the hydrolytic process and that evolutionary selection has condensed cellulase phenotypes near the line. One consequence of the LFER is that the activity of a cellulase can be estimated from its substrate binding strength, irrespectively of structural and mechanistic details, and this appears promising for in silico selection and design within this industrially important group of enzymes.
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Affiliation(s)
- Jeppe Kari
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Gustavo A Molina
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Kay S Schaller
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Corinna Schiano-di-Cola
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Stefan J Christensen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Silke F Badino
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Nanna S Røjel
- Department of Science and Environment, Roskilde University, Universitetsvej 1, Roskilde, Denmark
| | - Malene B Keller
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, Denmark
| | - Nanna Rolsted Sørensen
- Department of Science and Environment, Roskilde University, Universitetsvej 1, Roskilde, Denmark
| | - Bartlomiej Kolaczkowski
- Department of Science and Environment, Roskilde University, Universitetsvej 1, Roskilde, Denmark
| | | | | | | | | | - Günther H J Peters
- Department of Chemistry, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | | | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark.
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10
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Functionalization of Cellulose-Based Hydrogels with Bi-Functional Fusion Proteins Containing Carbohydrate-Binding Modules. MATERIALS 2021; 14:ma14123175. [PMID: 34207652 PMCID: PMC8227779 DOI: 10.3390/ma14123175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/01/2021] [Accepted: 06/04/2021] [Indexed: 01/14/2023]
Abstract
Materials with novel and enhanced functionalities can be obtained by modifying cellulose with a range of biomolecules. This functionalization can deliver tailored cellulose-based materials with enhanced physical and chemical properties and control of biological interactions that match specific applications. One of the foundations for the success of such biomaterials is to efficiently control the capacity to combine relevant biomolecules into cellulose materials in such a way that the desired functionality is attained. In this context, our main goal was to develop bi-functional biomolecular constructs for the precise modification of cellulose hydrogels with bioactive molecules of interest. The main idea was to use biomolecular engineering techniques to generate and purify different recombinant fusions of carbohydrate binding modules (CBMs) with significant biological entities. Specifically, CBM-based fusions were designed to enable the bridging of proteins or oligonucleotides with cellulose hydrogels. The work focused on constructs that combine a family 3 CBM derived from the cellulosomal-scaffolding protein A from Clostridium thermocellum (CBM3) with the following: (i) an N-terminal green fluorescent protein (GFP) domain (GFP-CBM3); (ii) a double Z domain that recognizes IgG antibodies; and (iii) a C-terminal cysteine (CBM3C). The ability of the CBM fusions to bind and/or anchor their counterparts onto the surface of cellulose hydrogels was evaluated with pull-down assays. Capture of GFP-CBM3 by cellulose was first demonstrated qualitatively by fluorescence microscopy. The binding of the fusion proteins, the capture of antibodies (by ZZ-CBM3), and the grafting of an oligonucleotide (to CBM3C) were successfully demonstrated. The bioactive cellulose platform described here enables the precise anchoring of different biomolecules onto cellulose hydrogels and could contribute significatively to the development of advanced medical diagnostic sensors or specialized biomaterials, among others.
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11
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Chundawat SPS, Nemmaru B, Hackl M, Brady SK, Hilton MA, Johnson MM, Chang S, Lang MJ, Huh H, Lee SH, Yarbrough JM, López CA, Gnanakaran S. Molecular origins of reduced activity and binding commitment of processive cellulases and associated carbohydrate-binding proteins to cellulose III. J Biol Chem 2021; 296:100431. [PMID: 33610545 PMCID: PMC8010709 DOI: 10.1016/j.jbc.2021.100431] [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: 06/04/2020] [Revised: 02/11/2021] [Accepted: 02/16/2021] [Indexed: 11/30/2022] Open
Abstract
Efficient enzymatic saccharification of cellulosic biomass into fermentable sugars can enable production of bioproducts like ethanol. Native crystalline cellulose, or cellulose I, is inefficiently processed via enzymatic hydrolysis but can be converted into the structurally distinct cellulose III allomorph that is processed via cellulase cocktails derived from Trichoderma reesei up to 20-fold faster. However, characterization of individual cellulases from T. reesei, like the processive exocellulase Cel7A, shows reduced binding and activity at low enzyme loadings toward cellulose III. To clarify this discrepancy, we monitored the single-molecule initial binding commitment and subsequent processive motility of Cel7A enzymes and associated carbohydrate-binding modules (CBMs) on cellulose using optical tweezers force spectroscopy. We confirmed a 48% lower initial binding commitment and 32% slower processive motility of Cel7A on cellulose III, which we hypothesized derives from reduced binding affinity of the Cel7A binding domain CBM1. Classical CBM–cellulose pull-down assays, depending on the adsorption model fitted, predicted between 1.2- and 7-fold reduction in CBM1 binding affinity for cellulose III. Force spectroscopy measurements of CBM1–cellulose interactions, along with molecular dynamics simulations, indicated that previous interpretations of classical binding assay results using multisite adsorption models may have complicated analysis, and instead suggest simpler single-site models should be used. These findings were corroborated by binding analysis of other type-A CBMs (CBM2a, CBM3a, CBM5, CBM10, and CBM64) on both cellulose allomorphs. Finally, we discuss how complementary analytical tools are critical to gain insight into the complex mechanisms of insoluble polysaccharides hydrolysis by cellulolytic enzymes and associated carbohydrate-binding proteins.
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Affiliation(s)
- Shishir P S Chundawat
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA.
| | - Bhargava Nemmaru
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Markus Hackl
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Sonia K Brady
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Mark A Hilton
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Madeline M Johnson
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Sungrok Chang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Matthew J Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Hyun Huh
- Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Sang-Hyuk Lee
- Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - John M Yarbrough
- Biosciences Center, National Renewable Energy Lab, Golden, Colorado, USA
| | - Cesar A López
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
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12
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Glasgow E, Vander Meulen K, Kuch N, Fox BG. Multifunctional cellulases are potent, versatile tools for a renewable bioeconomy. Curr Opin Biotechnol 2021; 67:141-148. [PMID: 33550093 PMCID: PMC8366578 DOI: 10.1016/j.copbio.2020.12.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/09/2020] [Accepted: 12/28/2020] [Indexed: 11/21/2022]
Abstract
Enzyme performance is critical to the future bioeconomy based on renewable plant materials. Plant biomass can be efficiently hydrolyzed by multifunctional cellulases (MFCs) into sugars suitable for conversion into fuels and chemicals, and MFCs fall into three functional categories. Recent work revealed MFCs with broad substrate specificity, dual exo-activity/endo-activity on cellulose, and intramolecular synergy, among other novel characteristics. Binding modules and accessory catalytic domains amplify MFC and xylanase activity in a wide variety of ways, and processive endoglucanases achieve autosynergy on cellulose. Multidomain MFCs from Caldicellulosiruptor are heat-tolerant, adaptable to variable cellulose crystallinity, and may provide interchangeable scaffolds for recombinant design. Further studies of MFC properties and their reactivity with plant biomass are recommended for increasing biorefinery yields.
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Affiliation(s)
- Evan Glasgow
- Dept. of Biochemistry, University of Wisconsin - Madison, 433 Babcock Dr., Madison, WI, 53706, United States; Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, 1552 University Ave, Madison, WI, 53726, United States
| | - Kirk Vander Meulen
- Dept. of Biochemistry, University of Wisconsin - Madison, 433 Babcock Dr., Madison, WI, 53706, United States; Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, 1552 University Ave, Madison, WI, 53726, United States
| | - Nate Kuch
- Dept. of Biochemistry, University of Wisconsin - Madison, 433 Babcock Dr., Madison, WI, 53706, United States; Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, 1552 University Ave, Madison, WI, 53726, United States
| | - Brian G Fox
- Dept. of Biochemistry, University of Wisconsin - Madison, 433 Babcock Dr., Madison, WI, 53706, United States; Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, 1552 University Ave, Madison, WI, 53726, United States.
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13
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Schaller KS, Kari J, Molina GA, Tidemand KD, Borch K, Peters GHJ, Westh P. Computing Cellulase Kinetics with a Two-Domain Linear Interaction Energy Approach. ACS OMEGA 2021; 6:1547-1555. [PMID: 33490814 PMCID: PMC7818601 DOI: 10.1021/acsomega.0c05361] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/24/2020] [Indexed: 05/21/2023]
Abstract
While heterogeneous enzyme reactions play an essential role in both nature and green industries, computational predictions of their catalytic properties remain scarce. Recent experimental work demonstrated the applicability of the Sabatier principle for heterogeneous biocatalysis. This provides a simple relationship between binding strength and the catalytic rate and potentially opens a new way for inexpensive computational determination of kinetic parameters. However, broader implementation of this approach will require fast and reliable prediction of binding free energies of complex two-phase systems, and computational procedures for this are still elusive. Here, we propose a new framework for the assessment of the binding strengths of multidomain proteins, in general, and interfacial enzymes, in particular, based on an extended linear interaction energy (LIE) method. This two-domain LIE (2D-LIE) approach was successfully applied to predict binding and activation free energies of a diverse set of cellulases and resulted in robust models with high accuracy. Overall, our method provides a fast computational screening tool for cellulases that have not been experimentally characterized, and we posit that it may also be applicable to other heterogeneously acting biocatalysts.
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Affiliation(s)
- Kay S. Schaller
- Department
of Biotechnology and Biomedicine, Technical
University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
- Department
of Chemistry, Technical University of Denmark, Kemitorvet, DK-2800 Kgs. Lyngby, Denmark
| | - Jeppe Kari
- Department
of Biotechnology and Biomedicine, Technical
University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
| | - Gustavo A. Molina
- Department
of Biotechnology and Biomedicine, Technical
University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
| | | | - Kim Borch
- Novozymes
A/S, Biologiens Vej 2, DK-2800 Kgs. Lyngby, Denmark
| | - Günther H. J. Peters
- Department
of Chemistry, Technical University of Denmark, Kemitorvet, DK-2800 Kgs. Lyngby, Denmark
| | - Peter Westh
- Department
of Biotechnology and Biomedicine, Technical
University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
- . Phone: +45 45 25 26 41
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14
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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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15
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Christensen SJ, Badino SF, Cavaleiro AM, Borch K, Westh P. Functional analysis of chimeric TrCel6A enzymes with different carbohydrate binding modules. Protein Eng Des Sel 2020; 32:401-409. [PMID: 32100026 DOI: 10.1093/protein/gzaa003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 01/10/2019] [Accepted: 01/13/2019] [Indexed: 11/14/2022] Open
Abstract
The glycoside hydrolase (GH) family 6 is an important group of enzymes that constitute an essential part of industrial enzyme cocktails used to convert lignocellulose into fermentable sugars. In nature, enzymes from this family often have a carbohydrate binding module (CBM) from the CBM family 1. These modules are known to promote adsorption to the cellulose surface and influence enzymatic activity. Here, we have investigated the functional diversity of CBMs found within the GH6 family. This was done by constructing five chimeric enzymes based on the model enzyme, TrCel6A, from the soft-rot fungus Trichoderma reesei. The natural CBM of this enzyme was exchanged with CBMs from other GH6 enzymes originating from different cellulose degrading fungi. The chimeric enzymes were expressed in the same host and investigated in adsorption and quasi-steady-state kinetic experiments. Our results quantified functional differences of these phylogenetically distant binding modules. Thus, the partitioning coefficient for substrate binding varied 4-fold, while the maximal turnover (kcat) showed a 2-fold difference. The wild-type enzyme showed the highest cellulose affinity on all tested substrates and the highest catalytic turnover. The CBM from Serendipita indica strongly promoted the enzyme's ability to form productive complexes with sites on the substrate surface but showed lower turnover of the complex. We conclude that the CBM plays an important role for the functional differences between GH6 wild-type enzymes.
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Affiliation(s)
- Stefan Jarl Christensen
- Research Unit for Functional Biomaterials, Department of Science and Environment, Roskilde University, building 28B, DK-4000, Roskilde, Denmark
| | - Silke Flindt Badino
- Research Unit for Functional Biomaterials, Department of Science and Environment, Roskilde University, building 28B, DK-4000, Roskilde, Denmark
| | - Ana Mafalda Cavaleiro
- Research Unit for Functional Biomaterials, Department of Science and Environment, Roskilde University, building 28B, DK-4000, Roskilde, Denmark.,Novozymes A/S, Department of Enzyme Discovery, Rævehøjvej 32A, DK-2800 Kgs. Lyngby, Denmark
| | - Kim Borch
- Novozymes A/S, Department of Enzyme Discovery, Rævehøjvej 32A, DK-2800 Kgs. Lyngby, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, building 224, DK-2800, Kgs. Lyngby, Denmark
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16
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Sørlie M, Horn SJ, Vaaje-Kolstad G, Eijsink VG. Using chitosan to understand chitinases and the role of processivity in the degradation of recalcitrant polysaccharides. REACT FUNCT POLYM 2020. [DOI: 10.1016/j.reactfunctpolym.2020.104488] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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17
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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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18
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Molecular recognition in the product site of cellobiohydrolase Cel7A regulates processive step length. Biochem J 2020; 477:99-110. [PMID: 31816027 DOI: 10.1042/bcj20190770] [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: 10/16/2019] [Revised: 12/06/2019] [Accepted: 12/09/2019] [Indexed: 11/17/2022]
Abstract
Cellobiohydrolase Cel7A is an industrial important enzyme that breaks down cellulose by a complex processive mechanism. The enzyme threads the reducing end of a cellulose strand into its tunnel-shaped catalytic domain and progresses along the strand while sequentially releasing the disaccharide cellobiose. While some molecular details of this intricate process have emerged, general structure-function relationships for Cel7A remain poorly elucidated. One interesting aspect is the occurrence of particularly strong ligand interactions in the product binding site. In this work, we analyze these interactions in Cel7A from Trichoderma reesei with special emphasis on the Arg251 and Arg394 residues. We made extensive biochemical characterization of enzymes that were mutated in these two positions and showed that the arginine residues contributed strongly to product binding. Specifically, ∼50% of the total standard free energy of product binding could be ascribed to four hydrogen bonds to Arg251 and Arg394, which had previously been identified in crystal structures. Mutation of either Arg251 or Arg394 lowered production inhibition of Cel7A, but at the same time altered the enzyme product profile and resulted in ∼50% reduction in both processivity and hydrolytic activity. The position of the two arginine residues closely matches the two-fold screw axis symmetry of the substrate, and this energetically favors the productive enzyme-substrate complex. Our results indicate that the strong and specific ligand interactions of Arg251 and Arg394 provide a simple proofreading system that controls the step length during consecutive hydrolysis and minimizes dead time associated with transient, non-productive complexes.
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19
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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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20
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Kołaczkowski BM, Schaller KS, Sørensen TH, Peters GHJ, Jensen K, Krogh KBRM, Westh P. Removal of N-linked glycans in cellobiohydrolase Cel7A from Trichoderma reesei reveals higher activity and binding affinity on crystalline cellulose. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:136. [PMID: 32782472 PMCID: PMC7412794 DOI: 10.1186/s13068-020-01779-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/29/2020] [Indexed: 05/15/2023]
Abstract
BACKGROUND Cellobiohydrolase from glycoside hydrolase family 7 is a major component of commercial enzymatic mixtures for lignocellulosic biomass degradation. For many years, Trichoderma reesei Cel7A (TrCel7A) has served as a model to understand structure-function relationships of processive cellobiohydrolases. The architecture of TrCel7A includes an N-glycosylated catalytic domain, which is connected to a carbohydrate-binding module through a flexible, O-glycosylated linker. Depending on the fungal expression host, glycosylation can vary not only in glycoforms, but also in site occupancy, leading to a complex pattern of glycans, which can affect the enzyme's stability and kinetics. RESULTS Two expression hosts, Aspergillus oryzae and Trichoderma reesei, were utilized to successfully express wild-types TrCel7A (WT Ao and WT Tr ) and the triple N-glycosylation site deficient mutants TrCel7A N45Q, N270Q, N384Q (ΔN-glyc Ao and ΔN-glyc Tr ). Also, we expressed single N-glycosylation site deficient mutants TrCel7A (N45Q Ao , N270Q Ao , N384Q Ao ). The TrCel7A enzymes were studied by steady-state kinetics under both substrate- and enzyme-saturating conditions using different cellulosic substrates. The Michaelis constant (K M ) was consistently found to be lowered for the variants with reduced N-glycosylation content, and for the triple deficient mutants, it was less than half of the WTs' value on some substrates. The ability of the enzyme to combine productively with sites on the cellulose surface followed a similar pattern on all tested substrates. Thus, site density (number of sites per gram cellulose) was 30-60% higher for the single deficient variants compared to the WT, and about twofold larger for the triple deficient enzyme. Molecular dynamic simulation of the N-glycan mutants TrCel7A revealed higher number of contacts between CD and cellulose crystal upon removal of glycans at position N45 and N384. CONCLUSIONS The kinetic changes of TrCel7A imposed by removal of N-linked glycans reflected modifications of substrate accessibility. The presence of N-glycans with extended structures increased K M and decreased attack site density of TrCel7A likely due to steric hindrance effect and distance between the enzyme and the cellulose surface, preventing the enzyme from achieving optimal conformation. This knowledge could be applied to modify enzyme glycosylation to engineer enzyme with higher activity on the insoluble substrates.
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Affiliation(s)
| | - Kay S. Schaller
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Building 224, 2800 Kgs. Lyngby, Denmark
| | | | - Günther H. J. Peters
- Department of Chemistry, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Biologiens Vej 2, 2800 Kgs. Lyngby, Denmark
| | | | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Building 224, 2800 Kgs. Lyngby, Denmark
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21
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Mudinoor AR, Goodwin PM, Rao RU, Karuna N, Hitomi A, Nill J, Jeoh T. Interfacial molecular interactions of cellobiohydrolase Cel7A and its variants on cellulose. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:10. [PMID: 31988662 PMCID: PMC6969433 DOI: 10.1186/s13068-020-1649-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/02/2020] [Indexed: 05/08/2023]
Abstract
BACKGROUND Molecular-scale mechanisms of the enzymatic breakdown of cellulosic biomass into fermentable sugars are still poorly understood, with a need for independent measurements of enzyme kinetic parameters. We measured binding times of cellobiohydrolase Trichoderma reesei Cel7A (Cel7A) on celluloses using wild-type Cel7A (WTintact), the catalytically deficient mutant Cel7A E212Q (E212Qintact) and their proteolytically isolated catalytic domains (CD) (WTcore and E212Qcore, respectively). The binding time distributions were obtained from time-resolved, super-resolution images of fluorescently labeled enzymes on cellulose obtained with total internal reflection fluorescence microscopy. RESULTS Binding of WTintact and E212Qintact on the recalcitrant algal cellulose (AC) showed two bound populations: ~ 85% bound with shorter residence times of < 15 s while ~ 15% were effectively immobilized. The similarity between binding times of the WT and E212Q suggests that the single point mutation in the enzyme active site does not affect the thermodynamics of binding of this enzyme. The isolated catalytic domains, WTcore and E212Qcore, exhibited three binding populations on AC: ~ 75% bound with short residence times of ~ 15 s (similar to the intact enzymes), ~ 20% bound for < 100 s and ~ 5% that were effectively immobilized. CONCLUSIONS Cel7A binding to cellulose is driven by the interactions between the catalytic domain and cellulose. The cellulose-binding module (CBM) and linker increase the affinity of Cel7A to cellulose likely by facilitating recognition and complexation at the substrate interface. The increased affinity of Cel7A to cellulose by the CBM and linker comes at the cost of increasing the population of immobilized enzyme on cellulose. The residence time (or inversely the dissociation rates) of Cel7A on cellulose is not catalysis limited.
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Affiliation(s)
- Akshata R. Mudinoor
- Biological and Agricultural Engineering, University of California, Davis, One Shields Ave., Davis, CA 95616 USA
| | - Peter M. Goodwin
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - Raghavendra U. Rao
- Gracenote, Inc., 2000 Powell Street, Suite 1500, Emeryville, CA 94608 USA
| | - Nardrapee Karuna
- Biological and Agricultural Engineering, University of California, Davis, One Shields Ave., Davis, CA 95616 USA
- Biotechnology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, 73000 Thailand
| | - Alex Hitomi
- Biological and Agricultural Engineering, University of California, Davis, One Shields Ave., Davis, CA 95616 USA
| | - Jennifer Nill
- Chemical Engineering, University of California, Davis, One Shields Ave., Davis, CA 95616 USA
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, CA 94720 USA
| | - Tina Jeoh
- Biological and Agricultural Engineering, University of California, Davis, One Shields Ave., Davis, CA 95616 USA
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22
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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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23
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Ahamed F, Song HS, Ooi CW, Ho YK. Modelling heterogeneity in cellulose properties predicts the slowdown phenomenon during enzymatic hydrolysis. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.05.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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24
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Zong Z, Li Q, Hong Z, Fu H, Cai W, Chipot C, Jiang H, Zhang D, Chen S, Shao X. Lysine Mutation of the Claw-Arm-Like Loop Accelerates Catalysis by Cellobiohydrolases. J Am Chem Soc 2019; 141:14451-14459. [DOI: 10.1021/jacs.9b08477] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Zhiyou Zong
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Qiyu Li
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Zhangyong Hong
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Haohao Fu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Wensheng Cai
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Christophe Chipot
- Laboratoire International Associé CNRS and University of Illinois at Urbana—Champaign, LPCT, UMR 7019 Universiteé de Lorraine CNRS, Vandœuvre-lès-Nancy F-54500, France
- Department of Physics, University of Illinois at Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Huifeng Jiang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Dongyuan Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Shulin Chen
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Xueguang Shao
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
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Petrášek Z, Eibinger M, Nidetzky B. Modeling the activity burst in the initial phase of cellulose hydrolysis by the processive cellobiohydrolase Cel7A. Biotechnol Bioeng 2019; 116:515-525. [PMID: 30515756 PMCID: PMC6590443 DOI: 10.1002/bit.26889] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 11/16/2018] [Accepted: 11/29/2018] [Indexed: 01/05/2023]
Abstract
The hydrolysis of cellulose by processive cellulases, such as exocellulase TrCel7A from Trichoderma reesei, is typically characterized by an initial burst of high activity followed by a slowdown, often leading to incomplete hydrolysis of the substrate. The origins of these limitations to cellulose hydrolysis are not yet fully understood. Here, we propose a new model for the initial phase of cellulose hydrolysis by processive cellulases, incorporating a bound but inactive enzyme state. The model, based on ordinary differential equations, accurately reproduces the activity burst and the subsequent slowdown of the cellulose hydrolysis and describes the experimental data equally well or better than the previously suggested model. We also derive steady‐state expressions that can be used to describe the pseudo‐steady state reached after the initial activity burst. Importantly, we show that the new model predicts the existence of an optimal enzyme‐substrate affinity at which the pseudo‐steady state hydrolysis rate is maximized. The model further allows the calculation of glucose production rate from the first cut in the processive run and reproduces the second activity burst commonly observed upon new enzyme addition. These results are expected to be applicable also to other processive enzymes.
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Affiliation(s)
- Zdeneˇk Petrášek
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Manuel Eibinger
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Graz, Austria.,Austrian Centre of Industrial Biotechnology, Graz, Austria
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26
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Kari J, Olsen JP, Jensen K, Badino SF, Krogh KBRM, Borch K, Westh P. Sabatier Principle for Interfacial (Heterogeneous) Enzyme Catalysis. ACS Catal 2018. [DOI: 10.1021/acscatal.8b03547] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Jeppe Kari
- Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Johan P. Olsen
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Silke F. Badino
- Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | | | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Peter Westh
- Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
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27
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28
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Christensen SJ, Kari J, Badino SF, Borch K, Westh P. Rate‐limiting step and substrate accessibility of cellobiohydrolase Cel6A from
Trichoderma reesei. FEBS J 2018; 285:4482-4493. [DOI: 10.1111/febs.14668] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 09/11/2018] [Accepted: 09/28/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Stefan J. Christensen
- Research Unit for Functional Biomaterials Department of Science and Environment Roskilde University Denmark
| | - Jeppe Kari
- Research Unit for Functional Biomaterials Department of Science and Environment Roskilde University Denmark
| | - Silke F. Badino
- Research Unit for Functional Biomaterials Department of Science and Environment Roskilde University Denmark
| | | | - Peter Westh
- Research Unit for Functional Biomaterials Department of Science and Environment Roskilde University Denmark
- Department of Biotechnology and Biomedicine Technical University of Denmark Lyngby Denmark
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29
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Du J, Zhang X, Li X, Zhao J, Liu G, Gao B, Qu Y. The cellulose binding region in Trichoderma reesei cellobiohydrolase I has a higher capacity in improving crystalline cellulose degradation than that of Penicillium oxalicum. BIORESOURCE TECHNOLOGY 2018; 266:19-25. [PMID: 29940438 DOI: 10.1016/j.biortech.2018.06.050] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 06/16/2018] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
Commercial cellulase preparations for lignocellulose bioconversion are mainly produced by the fungus Trichoderma reesei. The maximum cellulose conversion of T. reesei cellulase mixture was 15%-20% higher than that of Penicillium oxalicum in the hydrolysis of corncob residue and Avicel. Nevertheless, both preparations hydrolyzed more than 92% of cellulose in NaOH-mercerized Avicel. When added to Avicel hydrolysis residue that was less reactive to P. oxalicum cellulases, cellobiohydrolase I (CBH I) from T. reesei resulted in a higher cellulose conversion than its homologous proteins from P. oxalicum and Aspergillus niger at the same protein loadings. Further domain exchange experiment attributed the high hydrolytic efficiency of T. reesei CBH I to its inter-domain linker and cellulose-binding domain. The results in part explained the superior performance of T. reesei cellulases on the degradation of native crystalline cellulose, and highlighted the important role of cellulose-binding region in determining the degree of hydrolysis by cellulases.
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Affiliation(s)
- Jian Du
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China
| | - Xiu Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China; Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, Shandong, PR China.
| | - Baoyu Gao
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, Shandong, PR China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, PR China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, Shandong, PR China
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30
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Nakamura A, Okazaki KI, Furuta T, Sakurai M, Iino R. Processive chitinase is Brownian monorail operated by fast catalysis after peeling rail from crystalline chitin. Nat Commun 2018; 9:3814. [PMID: 30232340 PMCID: PMC6145945 DOI: 10.1038/s41467-018-06362-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/29/2018] [Indexed: 12/02/2022] Open
Abstract
Processive chitinase is a linear molecular motor which moves on the surface of crystalline chitin driven by processive hydrolysis of single chitin chain. Here, we analyse the mechanism underlying unidirectional movement of Serratia marcescens chitinase A (SmChiA) using high-precision single-molecule imaging, X-ray crystallography, and all-atom molecular dynamics simulation. SmChiA shows fast unidirectional movement of ~50 nm s-1 with 1 nm forward and backward steps, consistent with the length of reaction product chitobiose. Analysis of the kinetic isotope effect reveals fast substrate-assisted catalysis with time constant of ~3 ms. Decrystallization of the single chitin chain from crystal surface is the rate-limiting step of movement with time constant of ~17 ms, achieved by binding free energy at the product-binding site of SmChiA. Our results demonstrate that SmChiA operates as a burnt-bridge Brownian ratchet wherein the Brownian motion along the single chitin chain is rectified forward by substrate-assisted catalysis.
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Grants
- JP15H06898 Ministry of Education, Culture, Sports, Science, and Technology (MEXT)
- JP17K18429 Ministry of Education, Culture, Sports, Science, and Technology (MEXT)
- JP17H05899 Ministry of Education, Culture, Sports, Science, and Technology (MEXT)
- JP16H00789 Ministry of Education, Culture, Sports, Science, and Technology (MEXT)
- JP16H00858 Ministry of Education, Culture, Sports, Science, and Technology (MEXT)
- JP17K19213 Ministry of Education, Culture, Sports, Science, and Technology (MEXT)
- JP18H05424 Ministry of Education, Culture, Sports, Science, and Technology (MEXT)
- JP15H04366 Ministry of Education, Culture, Sports, Science, and Technology (MEXT)
- 01311805 MEXT | National Institutes of Natural Sciences (NINS)
- J281002 MEXT | National Institutes of Natural Sciences (NINS)
- Advanced Technology Institute Research Grants (RG2709)
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Affiliation(s)
- Akihiko Nakamura
- Institute for Molecular Science, National Institutes of Natural Sciences, 444-8787, Okazaki, Aichi, Japan.
- Department of Functional Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, 240-0193, Japan.
| | - Kei-Ichi Okazaki
- Institute for Molecular Science, National Institutes of Natural Sciences, 444-8787, Okazaki, Aichi, Japan
| | - Tadaomi Furuta
- Center for Biological Resources and Informatics, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
| | - Minoru Sakurai
- Center for Biological Resources and Informatics, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
| | - Ryota Iino
- Institute for Molecular Science, National Institutes of Natural Sciences, 444-8787, Okazaki, Aichi, Japan.
- Department of Functional Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, 240-0193, Japan.
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31
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Courtade G, Forsberg Z, Heggset EB, Eijsink VGH, Aachmann FL. The carbohydrate-binding module and linker of a modular lytic polysaccharide monooxygenase promote localized cellulose oxidation. J Biol Chem 2018; 293:13006-13015. [PMID: 29967065 DOI: 10.1074/jbc.ra118.004269] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 06/23/2018] [Indexed: 01/24/2023] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that catalyze the oxidative cleavage of polysaccharides such as cellulose and chitin, a feature that makes them key tools in industrial biomass conversion processes. The catalytic domains of a considerable fraction of LPMOs and other carbohydrate-active enzymes (CAZymes) are tethered to carbohydrate-binding modules (CBMs) by flexible linkers. These linkers preclude X-ray crystallographic studies, and the functional implications of these modular assemblies remain partly unknown. Here, we used NMR spectroscopy to characterize structural and dynamic features of full-length modular ScLPMO10C from Streptomyces coelicolor We observed that the linker is disordered and extended, creating distance between the CBM and the catalytic domain and allowing these domains to move independently of each other. Functional studies with cellulose nanofibrils revealed that most of the substrate-binding affinity of full-length ScLPMO10C resides in the CBM. Comparison of the catalytic performance of full-length ScLPMO10C and its isolated catalytic domain revealed that the CBM is beneficial for LPMO activity at lower substrate concentrations and promotes localized and repeated oxidation of the substrate. Taken together, these results provide a mechanistic basis for understanding the interplay between catalytic domains linked to CBMs in LPMOs and CAZymes in general.
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Affiliation(s)
- Gaston Courtade
- From NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway
| | - Zarah Forsberg
- the Faculty of Chemistry, Biotechnology and Food Science, NMBU Norwegian University of Life Sciences, N-1432 Ås, Norway, and
| | | | - Vincent G H Eijsink
- the Faculty of Chemistry, Biotechnology and Food Science, NMBU Norwegian University of Life Sciences, N-1432 Ås, Norway, and
| | - Finn L Aachmann
- From NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway,
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32
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Abstract
Glycoside Hydrolase Family 7 cellobiohydrolases (GH7 CBHs) catalyze cellulose depolymerization in cellulolytic eukaryotes, making them key discovery and engineering targets. However, there remains a lack of robust structure–activity relationships for these industrially important cellulases. Here, we compare CBHs from Trichoderma reesei (TrCel7A) and Penicillium funiculosum (PfCel7A), which exhibit a multi-modular architecture consisting of catalytic domain (CD), carbohydrate-binding module, and linker. We show that PfCel7A exhibits 60% greater performance on biomass than TrCel7A. To understand the contribution of each domain to this improvement, we measure enzymatic activity for a library of CBH chimeras with swapped subdomains, demonstrating that the enhancement is mainly caused by PfCel7A CD. We solve the crystal structure of PfCel7A CD and use this information to create a second library of TrCel7A CD mutants, identifying a TrCel7A double mutant with near-equivalent activity to wild-type PfCel7A. Overall, these results reveal CBH regions that enable targeted activity improvements. Cellobiohydrolases (CBHs) are critical for natural and industrial biomass degradation but their structure–activity relationships are not fully understood. Here, the authors present the biochemical and structural characterization of two CBHs, identifying protein regions that confer enhanced CBH activity.
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33
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Borisova AS, Eneyskaya EV, Jana S, Badino SF, Kari J, Amore A, Karlsson M, Hansson H, Sandgren M, Himmel ME, Westh P, Payne CM, Kulminskaya AA, Ståhlberg J. Correlation of structure, function and protein dynamics in GH7 cellobiohydrolases from Trichoderma atroviride, T. reesei and T. harzianum. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:5. [PMID: 29344086 PMCID: PMC5766984 DOI: 10.1186/s13068-017-1006-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/23/2017] [Indexed: 05/11/2023]
Abstract
BACKGROUND The ascomycete fungus Trichoderma reesei is the predominant source of enzymes for industrial conversion of lignocellulose. Its glycoside hydrolase family 7 cellobiohydrolase (GH7 CBH) TreCel7A constitutes nearly half of the enzyme cocktail by weight and is the major workhorse in the cellulose hydrolysis process. The orthologs from Trichoderma atroviride (TatCel7A) and Trichoderma harzianum (ThaCel7A) show high sequence identity with TreCel7A, ~ 80%, and represent naturally evolved combinations of cellulose-binding tunnel-enclosing loop motifs, which have been suggested to influence intrinsic cellobiohydrolase properties, such as endo-initiation, processivity, and off-rate. RESULTS The TatCel7A, ThaCel7A, and TreCel7A enzymes were characterized for comparison of function. The catalytic domain of TatCel7A was crystallized, and two structures were determined: without ligand and with thio-cellotriose in the active site. Initial hydrolysis of bacterial cellulose was faster with TatCel7A than either ThaCel7A or TreCel7A. In synergistic saccharification of pretreated corn stover, both TatCel7A and ThaCel7A were more efficient than TreCel7A, although TatCel7A was more sensitive to thermal inactivation. Structural analyses and molecular dynamics (MD) simulations were performed to elucidate important structure/function correlations. Moreover, reverse conservation analysis (RCA) of sequence diversity revealed divergent regions of interest located outside the cellulose-binding tunnel of Trichoderma spp. GH7 CBHs. CONCLUSIONS We hypothesize that the combination of loop motifs is the main determinant for the observed differences in Cel7A activity on cellulosic substrates. Fine-tuning of the loop flexibility appears to be an important evolutionary target in Trichoderma spp., a conclusion supported by the RCA data. Our results indicate that, for industrial use, it would be beneficial to combine loop motifs from TatCel7A with the thermostability features of TreCel7A. Furthermore, one region implicated in thermal unfolding is suggested as a primary target for protein engineering.
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Affiliation(s)
- Anna S. Borisova
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
- B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Orlova Roscha, Gatchina, Leningrad Region 188300 Russia
| | - Elena V. Eneyskaya
- B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Orlova Roscha, Gatchina, Leningrad Region 188300 Russia
| | - Suvamay Jana
- Department of Chemical and Materials Engineering, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046 USA
| | - Silke F. Badino
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Jeppe Kari
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Antonella Amore
- National Renewable Energy Laboratory, Biosciences Center, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Magnus Karlsson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, 750 07 Uppsala, Sweden
| | - Henrik Hansson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
| | - Michael E. Himmel
- National Renewable Energy Laboratory, Biosciences Center, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Peter Westh
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Christina M. Payne
- Department of Chemical and Materials Engineering, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046 USA
- Present Address: Division of Chemical, Bioengineering, Environmental, and Transport Systems, National Science Foundation, Alexandria, VA USA
| | - Anna A. Kulminskaya
- B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute”, Orlova Roscha, Gatchina, Leningrad Region 188300 Russia
- Department of Medical Physics, Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
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Badino SF, Bathke JK, Sørensen TH, Windahl MS, Jensen K, Peters GHJ, Borch K, Westh P. The influence of different linker modifications on the catalytic activity and cellulose affinity of cellobiohydrolase Cel7A from Hypocrea jecorina. Protein Eng Des Sel 2017; 30:495-501. [PMID: 28873985 DOI: 10.1093/protein/gzx036] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 07/04/2017] [Indexed: 12/13/2022] Open
Abstract
Various cellulases consist of a catalytic domain connected to a carbohydrate-binding module (CBM) by a flexible linker peptide. The linker if often strongly O-glycosylated and typically has a length of 20-50 amino acid residues. Functional roles, other than connecting the two folded domains, of the linker and its glycans, have been widely discussed, but experimental evidence remains sparse. One of the most studied cellulose degrading enzymes is the multi-domain cellobiohydrolase Cel7A from Hypocrea jecorina. Here, we designed variants of Cel7A with mutations in the linker region to elucidate the role of the linker. We found that moderate modification of the linker could result in significant changes in substrate affinity and catalytic efficacy. These changes were quite different for different linker variants. Thus, deletion of six residues near the catalytic domain had essentially no effects on enzyme function. Conversely, a substitution of four glycosylation sites near the middle of the linker reduced substrate affinity and increased maximal turnover. The observation of weaker binding provides some support of recent suggestions that linker glycans may be directly involved in substrate interactions. However, a variant with several inserted glycosylation sites near the CBM also showed lower affinity for the substrate compared to the wild-type, and we suggest that substrate interactions of the glycans depend on their exact location as well as other factors such as changes in structure and dynamics of the linker peptide.
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Affiliation(s)
- Silke Flindt Badino
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
| | - Jenny Kim Bathke
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Build. 207, DK-2800 Kgs. Lyngby, Denmark
| | - Trine Holst Sørensen
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
| | - Michael Skovbo Windahl
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Krogshøjvej 36, DK-2880, Bagsværd, Denmark
| | - Günther H J Peters
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Build. 207, DK-2800 Kgs. Lyngby, Denmark
| | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880, Bagsværd, Denmark
| | - Peter Westh
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
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35
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Single-molecule study of oxidative enzymatic deconstruction of cellulose. Nat Commun 2017; 8:894. [PMID: 29026070 PMCID: PMC5638905 DOI: 10.1038/s41467-017-01028-y] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 08/02/2017] [Indexed: 01/29/2023] Open
Abstract
LPMO (lytic polysaccharide monooxygenase) represents a unique paradigm of cellulosic biomass degradation by an oxidative mechanism. Understanding the role of LPMO in deconstructing crystalline cellulose is fundamental to the enzyme’s biological function and will help to specify the use of LPMO in biorefinery applications. Here we show with real-time atomic force microscopy that C1 and C4 oxidizing types of LPMO from Neurospora crassa (NcLPMO9F, NcLPMO9C) bind to nanocrystalline cellulose with high preference for the very same substrate surfaces that are also used by a processive cellulase (Trichoderma reesei CBH I) to move along during hydrolytic cellulose degradation. The bound LPMOs, however, are immobile during their adsorbed residence time ( ~ 1.0 min for NcLPMO9F) on cellulose. Treatment with LPMO resulted in fibrillation of crystalline cellulose and strongly ( ≥ 2-fold) enhanced the cellulase adsorption. It also increased enzyme turnover on the cellulose surface, thus boosting the hydrolytic conversion. Understanding the role of enzymes in biomass depolymerization is essential for the development of more efficient biorefineries. Here, the authors show by atomic force microscopy the real-time mechanism of cellulose deconstruction by lytic polysaccharide monooxygenases.
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36
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A quenched-flow system for measuring heterogeneous enzyme kinetics with sub-second time resolution. Enzyme Microb Technol 2017; 105:45-50. [DOI: 10.1016/j.enzmictec.2017.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 06/08/2017] [Accepted: 06/12/2017] [Indexed: 11/18/2022]
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37
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Kari J, Andersen M, Borch K, Westh P. An Inverse Michaelis–Menten Approach for Interfacial Enzyme Kinetics. ACS Catal 2017. [DOI: 10.1021/acscatal.7b00838] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeppe Kari
- Dept.
of Science and Environment, Roskilde University, 1 Universitetsvej, Building 28, DK-4000 Roskilde, Denmark
| | - Morten Andersen
- Dept.
of Science and Environment, Roskilde University, 1 Universitetsvej, Building 28, DK-4000 Roskilde, Denmark
| | - Kim Borch
- Novozymes A/S, Krogshøjvej
36, DK-2880 Bagsværd, Denmark
| | - Peter Westh
- Dept.
of Science and Environment, Roskilde University, 1 Universitetsvej, Building 28, DK-4000 Roskilde, Denmark
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38
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Kari J, Kont R, Borch K, Buskov S, Olsen JP, Cruyz-Bagger N, Väljamäe P, Westh P. Anomeric Selectivity and Product Profile of a Processive Cellulase. Biochemistry 2016; 56:167-178. [PMID: 28026938 DOI: 10.1021/acs.biochem.6b00636] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cellobiohydrolases (CBHs) make up an important group of enzymes for both natural carbon cycling and industrial deconstruction of lignocellulosic biomass. The consecutive hydrolysis of one cellulose strand relies on an intricate pattern of enzyme-substrate interactions in the long, tunnel-shaped binding site of the CBH. In this work, we have investigated the initial complexation mode with cellulose of the most thoroughly studied CBH, Cel7A from Hypocrea jecorina (HjCel7A). We found that HjCel7A predominantly produces glucose when it initiates a processive run on insoluble microcrystalline cellulose, confirming the validity of an even and odd product ratio as an estimate of processivity. Moreover, the glucose released from cellulose was predominantly α-glucose. A link between the initial binding mode of the enzyme and the reducing end configuration was investigated by inhibition studies with the two anomers of cellobiose. A clear preference for β-cellobiose in product binding site +2 was observed for HjCel7A, but not the homologous endoglucanase, HjCe7B. Possible relationships between this anomeric preference in the product site and the prevalence of odd-numbered initial-cut products are discussed, and a correlation between processivity and anomer selectivity is proposed.
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Affiliation(s)
- Jeppe Kari
- Research Unit for Functional Biomaterials, Roskilde University , Roskilde, Denmark
| | - Riin Kont
- Institute of Molecular and Cell Biology, University of Tartu , Tartu, Estonia
| | - Kim Borch
- Novozymes A/S , Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Steen Buskov
- Novozymes A/S , Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Johan Pelck Olsen
- Research Unit for Functional Biomaterials, Roskilde University , Roskilde, Denmark
| | | | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu , Tartu, Estonia
| | - Peter Westh
- Research Unit for Functional Biomaterials, Roskilde University , Roskilde, Denmark
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39
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Crystal structures of wild‐type
Trichoderma reesei
Cel7A catalytic domain in open and closed states. FEBS Lett 2016; 590:4429-4438. [DOI: 10.1002/1873-3468.12464] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/03/2016] [Accepted: 10/10/2016] [Indexed: 11/07/2022]
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40
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Kont R, Kari J, Borch K, Westh P, Väljamäe P. Inter-domain Synergism Is Required for Efficient Feeding of Cellulose Chain into Active Site of Cellobiohydrolase Cel7A. J Biol Chem 2016; 291:26013-26023. [PMID: 27780868 DOI: 10.1074/jbc.m116.756007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/21/2016] [Indexed: 01/27/2023] Open
Abstract
Structural polysaccharides like cellulose and chitin are abundant and their enzymatic degradation to soluble sugars is an important route in green chemistry. Processive glycoside hydrolases (GHs), like cellobiohydrolase Cel7A of Trichoderma reesei (TrCel7A) are key components of efficient enzyme systems. TrCel7A consists of a catalytic domain (CD) and a smaller carbohydrate-binding module (CBM) connected through the glycosylated linker peptide. A tunnel-shaped active site rests in the CD and contains 10 glucose unit binding sites. The active site of TrCel7A is lined with four Trp residues with two of them, Trp-40 and Trp-38, in the substrate binding sites near the tunnel entrance. Although addressed in numerous studies the elucidation of the role of CBM and active site aromatics has been obscured by a complex multistep mechanism of processive GHs. Here we studied the role of the CBM-linker and Trp-38 of TrCel7A with respect to binding affinity, on- and off-rates, processivity, and synergism with endoglucanase. The CBM-linker increased the on-rate and substrate affinity of the enzyme. The Trp-38 to Ala substitution resulted in increased off-rates and decreased processivity. The effect of the Trp-38 to Ala substitution on on-rates was strongly dependent on the presence of the CBM-linker. This compensation between CBM-linker and Trp-38 indicates synergism between CBM-linker and CD in feeding the cellulose chain into the active site. The inter-domain synergism was pre-requisite for the efficient degradation of cellulose in the presence of endoglucanase.
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Affiliation(s)
- Riin Kont
- From the Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia
| | - Jeppe Kari
- the Department of Science and Environment, Roskilde University, DK-4000 Roskilde, Denmark, and
| | - Kim Borch
- Novozymes A/S, Bagsværd DK-2880, Denmark
| | - Peter Westh
- the Department of Science and Environment, Roskilde University, DK-4000 Roskilde, Denmark, and
| | - Priit Väljamäe
- From the Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia,
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41
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Karuna N, Jeoh T. The productive cellulase binding capacity of cellulosic substrates. Biotechnol Bioeng 2016; 114:533-542. [PMID: 27696345 DOI: 10.1002/bit.26193] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 09/12/2016] [Accepted: 09/26/2016] [Indexed: 01/18/2023]
Abstract
Cellulosic biomass is the most promising feedstock for renewable biofuel production; however, the mechanisms of the heterogeneous cellulose saccharification reaction are still unsolved. As cellulases need to bind isolated molecules of cellulose at the surface of insoluble cellulose fibrils or larger aggregated cellulose structures in order to hydrolyze glycosidic bonds, the "accessibility of cellulose to cellulases" is considered to be a reaction limiting property of cellulose. We have defined the accessibility of cellulose to cellulases as the productive binding capacity of cellulose, that is, the concentration of productive binding sites on cellulose that are accessible for binding and hydrolysis by cellulases. Productive cellulase binding to cellulose results in hydrolysis and can be quantified by measuring hydrolysis rates. In this study, we measured the productive Trichoderma reesei Cel7A (TrCel7A) binding capacity of five cellulosic substrates from different sources and processing histories. Swollen filter paper and bacterial cellulose had higher productive binding capacities of ∼6 µmol/g while filter paper, microcrystalline cellulose, and algal cellulose had lower productive binding capacities of ∼3 µmol/g. Swelling and regenerating filter paper using phosphoric acid increased the initial accessibility of the reducing ends to TrCel7A from 4 to 6 µmol/g. Moreover, this increase in initial productive binding capacity accounted in large part for the difference in the overall digestibility between filter paper and swollen filter paper. We further demonstrated that an understanding of how the productive binding capacity declines over the course of the hydrolysis reaction has the potential to predict overall saccharification time courses. Biotechnol. Bioeng. 2017;114: 533-542. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Nardrapee Karuna
- Department of Biological and Agricultural Engineering, University of California, One Shields Ave., Davis 95616, California
| | - Tina Jeoh
- Department of Biological and Agricultural Engineering, University of California, One Shields Ave., Davis 95616, California
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42
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Sørensen TH, Windahl MS, McBrayer B, Kari J, Olsen JP, Borch K, Westh P. Loop variants of the thermophileRasamsonia emersoniiCel7A with improved activity against cellulose. Biotechnol Bioeng 2016; 114:53-62. [DOI: 10.1002/bit.26050] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/08/2016] [Accepted: 07/11/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Trine Holst Sørensen
- NSM, Research Unit for Functional Biomaterials, Roskilde University, Universitetsvej 1; Building 28, DK-4000 Roskilde Denmark
| | | | | | - Jeppe Kari
- NSM, Research Unit for Functional Biomaterials, Roskilde University, Universitetsvej 1; Building 28, DK-4000 Roskilde Denmark
| | - Johan Pelck Olsen
- NSM, Research Unit for Functional Biomaterials, Roskilde University, Universitetsvej 1; Building 28, DK-4000 Roskilde Denmark
| | | | - Peter Westh
- NSM, Research Unit for Functional Biomaterials, Roskilde University, Universitetsvej 1; Building 28, DK-4000 Roskilde Denmark
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43
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Cruys-Bagger N, Alasepp K, Andersen M, Ottesen J, Borch K, Westh P. Rate of Threading a Cellulose Chain into the Binding Tunnel of a Cellulase. J Phys Chem B 2016; 120:5591-600. [DOI: 10.1021/acs.jpcb.6b01877] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicolaj Cruys-Bagger
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
- Novozymes A/S, Krogshøjvej
36, DK-2880 Bagsværd, Denmark
| | - Kadri Alasepp
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Morten Andersen
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Johnny Ottesen
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Kim Borch
- Novozymes A/S, Krogshøjvej
36, DK-2880 Bagsværd, Denmark
| | - Peter Westh
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
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44
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Song X, Zhang S, Wang Y, Li J, He C, Yao L. A kinetic study of Trichoderma reesei Cel7B catalyzed cellulose hydrolysis. Enzyme Microb Technol 2016; 87-88:9-16. [PMID: 27178789 DOI: 10.1016/j.enzmictec.2016.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/28/2016] [Accepted: 02/18/2016] [Indexed: 11/28/2022]
Abstract
One prominent feature of Trichoderma reesei (Tr) endoglucanases catalyzed cellulose hydrolysis is that the reaction slows down quickly after it starts (within minutes). But the mechanism of the slowdown is not well understood. A structural model of Tr- Cel7B catalytic domain bound to cellulose was built computationally and the potentially important binding residues were identified and tested experimentally. The 13 tested mutants show different binding properties in the adsorption to phosphoric acid swollen cellulose and filter paper. Though the partitioning parameter to filter paper is about 10 times smaller than that to phosphoric acid swollen cellulose, a positive correlation is shown for two substrates. The kinetic studies show that the reactions slow down quickly for both substrates. This slowdown is not correlated to the binding constant but anticorrelated to the enzyme initial activity. The amount of reducing sugars released after 24h by Cel7B in phosphoric acid swollen cellulose, Avicel and filter paper cellulose hydrolysis is correlated with the enzyme activity against a soluble substrate p-nitrophenyl lactoside. Six of the 13 tested mutants, including N47A, N52D, S99A, N323D, S324A, and S346A, yield ∼15-35% more reducing sugars than the wild type (WT) Cel7B in phosphoric acid swollen cellulose and filter paper hydrolysis. This study reveals that the slowdown of the reaction is not due to the binding of the enzyme to cellulose. The activity of Tr- Cel7B against the insoluble substrate cellulose is determined by the enzyme's capability in hydrolyzing the soluble substrate.
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Affiliation(s)
- Xiangfei Song
- Shandong Provincial Key Laboratory of Synthetic Biology, Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China
| | - Shujun Zhang
- Shandong Provincial Key Laboratory of Synthetic Biology, Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China
| | - Yefei Wang
- Shandong Provincial Key Laboratory of Synthetic Biology, Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China
| | - Jingwen Li
- Shandong Provincial Key Laboratory of Synthetic Biology, Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China
| | - Chunyan He
- Shandong Provincial Key Laboratory of Synthetic Biology, Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China
| | - Lishan Yao
- Shandong Provincial Key Laboratory of Synthetic Biology, Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266061, China.
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45
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Wallace J, Brienzo M, García-Aparicio MP, Görgens JF. Lignin enrichment and enzyme deactivation as the root cause of enzymatic hydrolysis slowdown of steam pretreated sugarcane bagasse. N Biotechnol 2016; 33:361-71. [PMID: 26820122 DOI: 10.1016/j.nbt.2016.01.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 11/25/2015] [Accepted: 01/14/2016] [Indexed: 01/21/2023]
Abstract
The enzymatic hydrolysis (EH) rate normally decreases during the hydrolysis, leaving unhydrolyzed material as residue. This phenomenon occurs during the hydrolysis of both cellulose (avicel) and lignocellulosic material, in nature or even pretreated. The progression of EH of steam pretreated sugarcane bagasse was associated with an initial (fast), intermediate (slower) and recalcitrant (slowest) phases, at glucan to glucose conversion yields of 61.7, 81.6 and 86%, respectively. Even though the EH of avicel as a simpler material than steam pretreated sugarcane bagasse, EH slowdown was present. The less thermo-stable endo-xylanase lost 58% of initial enzyme activity, followed by β-glucosidase that lost 16%, culminating in FPase activity loss of 30% in the first 24hours. After 72hours of EH the total loss of FPase activity was 40% compared to the initial activity. Analysis of the solid residue from EH showed that lignin content, phenolic compounds and ash increased while glucan decreased as hydrolysis progressed. During the initial fast phase of EH, the total solid residue surface area consisted predominantly of internal surface area. Thereafter, in the intermediate and recalcitrant phases of EH, the ratio of external:internal surface area increased. The proposed fiber damage and decrease in internal surface area, probably by EH action, was visualized by scanning electron microscopy imagery. The higher lignin/glucan ratio as EH progressed and enzyme deactivation by thermo instability were the main effects observed, respectively to substrate and enzyme.
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Affiliation(s)
- Joshua Wallace
- Department of Process Engineering, University of Stellenbosch, Private Bag X1, Stellenbosch 7602, South Africa
| | - Michel Brienzo
- Department of Process Engineering, University of Stellenbosch, Private Bag X1, Stellenbosch 7602, South Africa.
| | - María P García-Aparicio
- Department of Process Engineering, University of Stellenbosch, Private Bag X1, Stellenbosch 7602, South Africa; Department of Microbiology, University of Stellenbosch, Private Bag X1, Stellenbosch 7602, South Africa
| | - Johann F Görgens
- Department of Process Engineering, University of Stellenbosch, Private Bag X1, Stellenbosch 7602, South Africa
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46
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Cellobiohydrolase 1 from Trichoderma reesei degrades cellulose in single cellobiose steps. Nat Commun 2015; 6:10149. [PMID: 26657780 PMCID: PMC4682103 DOI: 10.1038/ncomms10149] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 11/09/2015] [Indexed: 12/02/2022] Open
Abstract
Cellobiohydrolase 1 from Trichoderma reesei (TrCel7A) processively hydrolyses cellulose into cellobiose. Although enzymatic techniques have been established as promising tools in biofuel production, a clear understanding of the motor's mechanistic action has yet to be revealed. Here, we develop an optical tweezers-based single-molecule (SM) motility assay for precision tracking of TrCel7A. Direct observation of motility during degradation reveals processive runs and distinct steps on the scale of 1 nm. Our studies suggest TrCel7A is not mechanically limited, can work against 20 pN loads and speeds up when assisted. Temperature-dependent kinetic studies establish the energy requirements for the fundamental stepping cycle, which likely includes energy from glycosidic bonds and other sources. Through SM measurements of isolated TrCel7A domains, we determine that the catalytic domain alone is sufficient for processive motion, providing insight into TrCel7A's molecular motility mechanism. Cellobiohydrolases are promising tools in biofuel production by hydrolysing cellulose into cellobiose. Here the authors use optical tweezers to show that Cellobiohydrolase 1 from Tricodermia reesei functions processively against moderate load, and likely uses multiple energy sources to fuel each step along the cellulose fibre.
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47
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Kurašin M, Kuusk S, Kuusk P, Sørlie M, Väljamäe P. Slow Off-rates and Strong Product Binding Are Required for Processivity and Efficient Degradation of Recalcitrant Chitin by Family 18 Chitinases. J Biol Chem 2015; 290:29074-85. [PMID: 26468285 DOI: 10.1074/jbc.m115.684977] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Indexed: 12/18/2022] Open
Abstract
Processive glycoside hydrolases are the key components of enzymatic machineries that decompose recalcitrant polysaccharides, such as chitin and cellulose. The intrinsic processivity (P(Intr)) of cellulases has been shown to be governed by the rate constant of dissociation from polymer chain (koff). However, the reported koff values of cellulases are strongly dependent on the method used for their measurement. Here, we developed a new method for determining koff, based on measuring the exchange rate of the enzyme between a non-labeled and a (14)C-labeled polymeric substrate. The method was applied to the study of the processive chitinase ChiA from Serratia marcescens. In parallel, ChiA variants with weaker binding of the N-acetylglucosamine unit either in substrate-binding site -3 (ChiA-W167A) or the product-binding site +1 (ChiA-W275A) were studied. Both ChiA variants showed increased off-rates and lower apparent processivity on α-chitin. The rate of the production of insoluble reducing groups on the reduced α-chitin was an order of magnitude higher than koff, suggesting that the enzyme can initiate several processive runs without leaving the substrate. On crystalline chitin, the general activity of the wild type enzyme was higher, and the difference was magnifying with hydrolysis time. On amorphous chitin, the variants clearly outperformed the wild type. A model is proposed whereby strong interactions with polymer in the substrate-binding sites (low off-rates) and strong binding of the product in the product-binding sites (high pushing potential) are required for the removal of obstacles, like disintegration of chitin microfibrils.
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Affiliation(s)
| | - Silja Kuusk
- From the Institutes of Molecular and Cell Biology and
| | - Piret Kuusk
- Physics, University of Tartu, 51010 Tartu, Estonia and
| | - Morten Sørlie
- the Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås 1432, Norway
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48
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Sørensen TH, Cruys-Bagger N, Borch K, Westh P. Free Energy Diagram for the Heterogeneous Enzymatic Hydrolysis of Glycosidic Bonds in Cellulose. J Biol Chem 2015; 290:22203-11. [PMID: 26183776 DOI: 10.1074/jbc.m115.659656] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 01/25/2023] Open
Abstract
Kinetic and thermodynamic data have been analyzed according to transition state theory and a simplified reaction scheme for the enzymatic hydrolysis of insoluble cellulose. For the cellobiohydrolase Cel7A from Hypocrea jecorina (Trichoderma reesei), we were able to measure or collect relevant values for all stable and activated complexes defined by the reaction scheme and hence propose a free energy diagram for the full heterogeneous process. For other Cel7A enzymes, including variants with and without carbohydrate binding module (CBM), we obtained activation parameters for the association and dissociation of the enzyme-substrate complex. The results showed that the kinetics of enzyme-substrate association (i.e. formation of the Michaelis complex) was almost entirely entropy-controlled and that the activation entropy corresponded approximately to the loss of translational and rotational degrees of freedom of the dissolved enzyme. This implied that the transition state occurred early in the path where the enzyme has lost these degrees of freedom but not yet established extensive contact interactions in the binding tunnel. For dissociation, a similar analysis suggested that the transition state was late in the path where most enzyme-substrate contacts were broken. Activation enthalpies revealed that the rate of dissociation was far more temperature-sensitive than the rates of both association and the inner catalytic cycle. Comparisons of one- and two-domain variants showed that the CBM had no influence on the transition state for association but increased the free energy barrier for dissociation. Hence, the CBM appeared to promote the stability of the complex by delaying dissociation rather than accelerating association.
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Affiliation(s)
- Trine Holst Sørensen
- From Roskilde University, NSM, Research Unit for Functional Biomaterials, 1 Universitetsvej, Building 28, DK-4000 Roskilde, Denmark and
| | - Nicolaj Cruys-Bagger
- From Roskilde University, NSM, Research Unit for Functional Biomaterials, 1 Universitetsvej, Building 28, DK-4000 Roskilde, Denmark and
| | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Peter Westh
- From Roskilde University, NSM, Research Unit for Functional Biomaterials, 1 Universitetsvej, Building 28, DK-4000 Roskilde, Denmark and
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49
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Kuusk S, Sørlie M, Väljamäe P. The predominant molecular state of bound enzyme determines the strength and type of product inhibition in the hydrolysis of recalcitrant polysaccharides by processive enzymes. J Biol Chem 2015; 290:11678-91. [PMID: 25767120 DOI: 10.1074/jbc.m114.635631] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Indexed: 11/06/2022] Open
Abstract
Processive enzymes are major components of the efficient enzyme systems that are responsible for the degradation of the recalcitrant polysaccharides cellulose and chitin. Despite intensive research, there is no consensus on which step is rate-limiting for these enzymes. Here, we performed a comparative study of two well characterized enzymes, the cellobiohydrolase Cel7A from Hypocrea jecorina and the chitinase ChiA from Serratia marcescens. Both enzymes were inhibited by their disaccharide product, namely chitobiose for ChiA and cellobiose for Cel7A. The products behaved as noncompetitive inhibitors according to studies using the (14)C-labeled crystalline polymeric substrates (14)C chitin nanowhiskers and (14)C-labeled bacterial microcrystalline cellulose for ChiA and Cel7A, respectively. The resulting observed Ki (obs) values were 0.45 ± 0.08 mm for ChiA and 0.17 ± 0.02 mm for Cel7A. However, in contrast to ChiA, the Ki (obs) of Cel7A was an order of magnitude higher than the true Ki value governed by the thermodynamic stability of the enzyme-inhibitor complex. Theoretical analysis of product inhibition suggested that the inhibition strength and pattern can be accounted for by assuming different rate-limiting steps for ChiA and Cel7A. Measuring the population of enzymes whose active site was occupied by a polymer chain revealed that Cel7A was bound predominantly via its active site. Conversely, the active-site-mediated binding of ChiA was slow, and most ChiA exhibited a free active site, even when the substrate concentration was saturating for the activity. Collectively, our data suggest that complexation with the polymer chain is rate-limiting for ChiA, whereas Cel7A is limited by dissociation.
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Affiliation(s)
- Silja Kuusk
- From the Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia and
| | - Morten Sørlie
- the Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Priit Väljamäe
- From the Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia and
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50
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Payne CM, Knott BC, Mayes HB, Hansson H, Himmel ME, Sandgren M, Ståhlberg J, Beckham GT. Fungal Cellulases. Chem Rev 2015; 115:1308-448. [DOI: 10.1021/cr500351c] [Citation(s) in RCA: 533] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Christina M. Payne
- Department
of Chemical and Materials Engineering and Center for Computational
Sciences, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, Kentucky 40506, United States
| | - Brandon C. Knott
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
| | - Heather B. Mayes
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Henrik Hansson
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Michael E. Himmel
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Mats Sandgren
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Jerry Ståhlberg
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Gregg T. Beckham
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
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