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Wu J, Lv J, Zhao L, Zhao R, Gao T, Xu Q, Liu D, Yu Q, Ma F. Exploring the role of microbial proteins in controlling environmental pollutants based on molecular simulation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167028. [PMID: 37704131 DOI: 10.1016/j.scitotenv.2023.167028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 09/03/2023] [Accepted: 09/10/2023] [Indexed: 09/15/2023]
Abstract
Molecular simulation has been widely used to study microbial proteins' structural composition and dynamic properties, such as volatility, flexibility, and stability at the microscopic scale. Herein, this review describes the key elements of molecular docking and molecular dynamics (MD) simulations in molecular simulation; reviews the techniques combined with molecular simulation, such as crystallography, spectroscopy, molecular biology, and machine learning, to validate simulation results and bridge information gaps in the structure, microenvironmental changes, expression mechanisms, and intensity quantification; illustrates the application of molecular simulation, in characterizing the molecular mechanisms of interaction of microbial proteins with four different types of contaminants, namely heavy metals (HMs), pesticides, dyes and emerging contaminants (ECs). Finally, the review outlines the important role of molecular simulations in the study of microbial proteins for controlling environmental contamination and provides ideas for the application of molecular simulation in screening microbial proteins and incorporating targeted mutagenesis to obtain more effective contaminant control proteins.
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Affiliation(s)
- Jieting Wu
- School of Environmental Science, Liaoning University, Shenyang 110036, China
| | - Jin Lv
- School of Environmental Science, Liaoning University, Shenyang 110036, China
| | - Lei Zhao
- State Key Laboratory of Urban Water Resources & Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Ruofan Zhao
- School of Environment, Beijing Normal University, Beijing 100875, China
| | - Tian Gao
- Key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Xikang Road #1, Nanjing 210098, China
| | - Qi Xu
- PetroChina Fushun Petrochemical Company, Fushun 113000, China
| | - Dongbo Liu
- School of Environmental Science, Liaoning University, Shenyang 110036, China
| | - Qiqi Yu
- School of Environmental Science, Liaoning University, Shenyang 110036, China
| | - Fang Ma
- State Key Laboratory of Urban Water Resources & Environment, Harbin Institute of Technology, Harbin 150090, China.
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2
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Gonçalves AL, Cunha PM, da Silva Lima A, Dos Santos JC, Segato F. Production of recombinant lytic polysaccharide monooxygenases and evaluation effect of its addition into Aspergillus fumigatus var. niveus cocktail for sugarcane bagasse saccharification. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2023; 1871:140919. [PMID: 37164048 DOI: 10.1016/j.bbapap.2023.140919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/01/2023] [Accepted: 05/03/2023] [Indexed: 05/12/2023]
Abstract
Lignocellulosic biomass is a promising alternative for producing biofuels, despite its recalcitrant nature. There are microorganisms in nature capable of efficiently degrade biomass, such as the filamentous fungi. Among them, Aspergillus fumigatus var. niveus (AFUMN) has a wide variety of carbohydrate-active enzymes (CAZymes), especially hydrolases, but a low number of oxidative enzymes in its genome. To confirm the enzymatic profile of this fungus, this study analyzed the secretome of AFUMN cultured in sugarcane bagasse as the sole carbon source. As expected, the secretome showed a predominance of hydrolytic enzymes compared to oxidative activity. However, it is known that hydrolytic enzymes act in synergy with oxidative proteins to efficiently degrade cellulose polymer, such as the Lytic Polysaccharide Monooxygenases (LPMOs). Thus, three LPMOs from the fungus Thermothelomyces thermophilus (TtLPMO9D, TtLPMO9H, and TtLPMO9O) were selected, heterologous expressed in Aspergillus nidulans, purified, and used to supplement the AFUMN secretome to evaluate their effect on the saccharification of sugarcane bagasse. The saccharification assay was carried out using different concentrations of AFUMN secretome supplemented with recombinant T. thermophilus LPMOs, as well as ascorbic acid as reducing agent for oxidative enzymes. Through a statistic design created by Design-Expert software, we were able to analyze a possible cooperative effect between these components. The results indicated that, in general, the addition of TtLPMO9D and ascorbic acid did not favor the conversion process in this study, while TtLPMO9O had a highly significant cooperative effect in bagasse saccharification compared to the control using only AFUMN secretome.
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Affiliation(s)
- Aline Larissa Gonçalves
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Paula Macedo Cunha
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Awana da Silva Lima
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Júlio César Dos Santos
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Fernando Segato
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
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3
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Dodda SR, Hossain M, Jain P, Aikat K, Mukhopadhyay SS. Comparative Biochemical and Structural Properties of an Industrially Important Biocatalyst Cellobiohydrolase Cel7A from Thermophilic Aspergillus fumigatus. APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s0003683822050064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Gado JE, Harrison BE, Sandgren M, Ståhlberg J, Beckham GT, Payne CM. Machine learning reveals sequence-function relationships in family 7 glycoside hydrolases. J Biol Chem 2021; 297:100931. [PMID: 34216620 PMCID: PMC8329511 DOI: 10.1016/j.jbc.2021.100931] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 06/18/2021] [Accepted: 06/29/2021] [Indexed: 11/28/2022] Open
Abstract
Family 7 glycoside hydrolases (GH7) are among the principal enzymes for cellulose degradation in nature and industrially. These enzymes are often bimodular, including a catalytic domain and carbohydrate-binding module (CBM) attached via a flexible linker, and exhibit an active site that binds cello-oligomers of up to ten glucosyl moieties. GH7 cellulases consist of two major subtypes: cellobiohydrolases (CBH) and endoglucanases (EG). Despite the critical importance of GH7 enzymes, there remain gaps in our understanding of how GH7 sequence and structure relate to function. Here, we employed machine learning to gain data-driven insights into relationships between sequence, structure, and function across the GH7 family. Machine-learning models, trained only on the number of residues in the active-site loops as features, were able to discriminate GH7 CBHs and EGs with up to 99% accuracy, demonstrating that the lengths of loops A4, B2, B3, and B4 strongly correlate with functional subtype across the GH7 family. Classification rules were derived such that specific residues at 42 different sequence positions each predicted the functional subtype with accuracies surpassing 87%. A random forest model trained on residues at 19 positions in the catalytic domain predicted the presence of a CBM with 89.5% accuracy. Our machine learning results recapitulate, as top-performing features, a substantial number of the sequence positions determined by previous experimental studies to play vital roles in GH7 activity. We surmise that the yet-to-be-explored sequence positions among the top-performing features also contribute to GH7 functional variation and may be exploited to understand and manipulate function.
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Affiliation(s)
- Japheth E Gado
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA; Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Brent E Harrison
- Department of Computer Science, University of Kentucky, Lexington, Kentucky, USA
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Gregg T Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Christina M Payne
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA.
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5
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Velasco J, de Oliveira Arnoldi Pellegrini V, Sepulchro AGV, Kadowaki MAS, Santo MCE, Polikarpov I, Segato F. Comparative analysis of two recombinant LPMOs from Aspergillus fumigatus and their effects on sugarcane bagasse saccharification. Enzyme Microb Technol 2021; 144:109746. [PMID: 33541573 DOI: 10.1016/j.enzmictec.2021.109746] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/11/2020] [Accepted: 12/30/2020] [Indexed: 01/19/2023]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) have been introduced into industrial cocktails used for biomass saccharification due to their capacity to boost enzymatic conversion of recalcitrant cellulose. The genome of the thermotolerant ascomycete Aspergillus fumigatus encodes 7 genes for LPMOs that belong to auxiliary activity family 9 (AA9). Here, we cloned, successfully expressed and performed biochemical evaluation of two CBM-less A. fumigatus LPMOs (AfAA9A and AfAA9B). A high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) analysis demonstrated that AfAA9A and AfAA9B are able to oxide cellulose at C1 and C1/C4 positions, respectively. Synergic effects of LPMOs (separately and in combination) with cellulases were investigated. Supplementation of Celluclast 1.5 L with a low concentration of AfAA9B improved in 20 % the saccharification of sugarcane bagasse pretreated by steam explosion (SEB), while AfAA9A did not improvethe saccharification. Analysis of the hydrolyzed biomass by confocal laser scanning microscopy (CLSM) showed the LPMOs are promoting lignin oxidation in the lignocellulosic material. This study complements the available results concerning the utilization of LPMOs in the enzymatic saccharification of lignocellulosic biomass.
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Affiliation(s)
- Josman Velasco
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | | | | | | | | | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, São Carlos, SP, Brazil.
| | - Fernando Segato
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
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6
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Fülöp L, Ecker J. An overview of biomass conversion: exploring new opportunities. PeerJ 2020; 8:e9586. [PMID: 32765969 PMCID: PMC7382363 DOI: 10.7717/peerj.9586] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/30/2020] [Indexed: 12/28/2022] Open
Abstract
Recycling biomass is indispensable these days not only because fossil energy sources are gradually depleted, but also because pollution of the environment, caused by the increasing use of energy, must be reduced. This article intends to overview the results of plant biomass processing methods that are currently in use. Our aim was also to review published methods that are not currently in use. It is intended to explore the possibilities of new methods and enzymes to be used in biomass recycling. The results of this overview are perplexing in almost every area. Advances have been made in the pre-treatment of biomass and in the diversity and applications of the enzymes utilized. Based on molecular modeling, very little progress has been made in the modification of existing enzymes for altered function and adaptation for the environmental conditions during the processing of biomass. There are hardly any publications in which molecular modeling techniques are used to improve enzyme function and to adapt enzymes to various environmental conditions. Our view is that using modern computational, biochemical, and biotechnological methods would enable the purposeful design of enzymes that are more efficient and suitable for biomass processing.
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Affiliation(s)
- László Fülöp
- Department of Chemistry, Szent István University, Gödöllő, Hungary
| | - János Ecker
- Department of Chemistry, Szent István University, Gödöllő, Hungary
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7
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Kari J, Christensen SJ, Andersen M, Baiget SS, Borch K, Westh P. A practical approach to steady-state kinetic analysis of cellulases acting on their natural insoluble substrate. Anal Biochem 2019; 586:113411. [PMID: 31520594 DOI: 10.1016/j.ab.2019.113411] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/26/2019] [Accepted: 08/28/2019] [Indexed: 10/26/2022]
Abstract
Measurement of steady-state rates (vSS) is straightforward in standard enzymology with soluble substrate, and it has been instrumental for comparative biochemical analyses within this area. For insoluble substrate, however, experimental values of vss remain controversial, and this has strongly limited the amount and quality of comparative analyses for cellulases and other enzymes that act on the surface of an insoluble substrate. In the current work, we have measured progress curves over a wide range of conditions for two cellulases, TrCel6A and TrCel7A from Trichoderma reesei, acting on their natural, insoluble substrate, cellulose. Based on this, we consider practical compromises for the determination of experimental vSS values, and propose a basic protocol that provides representative reaction rates and is experimentally simple so that larger groups of enzymes and conditions can be readily assayed with standard laboratory equipment. We surmise that the suggested experimental approach can be useful in comparative biochemical studies of cellulases; an area that remains poorly developed.
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Affiliation(s)
- Jeppe Kari
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800, Kgs. Lyngby, Denmark
| | - Stefan Jarl Christensen
- Department of Science and Environment, Roskilde University, Universitetsvej, Build. 28.C, DK-4000, Roskilde, Denmark
| | - Morten Andersen
- Department of Science and Environment, Roskilde University, Universitetsvej, Build. 28.C, DK-4000, Roskilde, Denmark
| | | | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880, Bagsværd, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800, Kgs. Lyngby, Denmark.
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8
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Pena CE, Costa MGS, Batista PR. Glycosylation effects on the structure and dynamics of a full-length Cel7A cellulase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1868:140248. [PMID: 31279935 DOI: 10.1016/j.bbapap.2019.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 06/27/2019] [Accepted: 07/02/2019] [Indexed: 11/17/2022]
Abstract
Fungi cellulases are used to degrade cellulose-containing biomass for bioethanol production. Industrial cellulases such as Cel7A from Trichoderma reesei (TrCel7A) are critical in this process. Thus, the understanding of structure and dynamics is crucial for engineering variants with improved cellulolytic activity. This cellulase consists of two domains connected by a flexible and highly glycosylated linker. However, the linker flexibility has hindered the determination of Cel7A complete structure. Herein, based on atomic and sparse data, we applied integrative modelling to build a model of the complete enzyme structure. Next, through simulations, we studied the glycosylation effects on the structure and dynamics of a solubilized TrCel7A. Essential dynamics analysis showed that O-glycosylation in the linker led to the stabilization of protein overall dynamics. O-linked glycans seem to restrict protein dihedral angles distribution in this region, selecting more elongated conformations. Besides the reduced flexibility, functional interdomain motions occurred in a more concerted way in the glycosylated system. In contrast, in the absence of glycosylation, we observed vast conformational plasticity with the functional domains frequently collapsing. We report here evidence that targeting Cel7A linker flexibility by point mutations including modification of glycosylation sites could be a promising design strategy to improve cellulase activity.
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Affiliation(s)
- Carlos Eduardo Pena
- Fundação Oswaldo Cruz, Programa de Computação Científica, Rio de Janeiro 21040-900, Brazil; Instituto Oswaldo Cruz, Programa de Pós-graduação em Biologia Computacional e Sistemas, Rio de Janeiro 21040-900, Brazil
| | - Mauricio G S Costa
- Fundação Oswaldo Cruz, Programa de Computação Científica, Rio de Janeiro 21040-900, Brazil; Instituto Oswaldo Cruz, Programa de Pós-graduação em Biologia Computacional e Sistemas, Rio de Janeiro 21040-900, Brazil; École Normale Supérieure Paris-Saclay, Laboratoire de Biologie et Pharmacologie Appliquée, Cachan 94235, France
| | - Paulo Ricardo Batista
- Fundação Oswaldo Cruz, Programa de Computação Científica, Rio de Janeiro 21040-900, Brazil; Instituto Oswaldo Cruz, Programa de Pós-graduação em Biologia Computacional e Sistemas, Rio de Janeiro 21040-900, Brazil.
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9
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Cai LN, Xu SN, Lu T, Lin DQ, Yao SJ. Directed expression of halophilic and acidophilic β-glucosidases by introducing homologous constitutive expression cassettes in marine Aspergillus niger. J Biotechnol 2019; 292:12-22. [DOI: 10.1016/j.jbiotec.2018.12.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 12/18/2018] [Accepted: 12/29/2018] [Indexed: 01/31/2023]
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10
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Rabinovich ML, Melnik MS, Herner ML, Voznyi YV, Vasilchenko LG. Predominant Nonproductive Substrate Binding by Fungal Cellobiohydrolase I and Implications for Activity Improvement. Biotechnol J 2018; 14:e1700712. [PMID: 29781240 DOI: 10.1002/biot.201700712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 05/08/2018] [Indexed: 12/20/2022]
Abstract
Enzymatic conversion of the most abundant renewable source of organic compounds, cellulose to fermentable sugars is attractive for production of green fuels and chemicals. The major component of industrial enzyme systems, cellobiohydrolase I from Hypocrea jecorina (Trichoderma reesei) (HjCel7A) processively splits disaccharide units from the reducing ends of tightly packed cellulose chains. HjCel7A consists of a catalytic domain (CD) and a carbohydrate-binding module (CBM) separated by a linker peptide. A tunnel-shaped substrate-binding site in the CD includes nine subsites for β-d-glucose units, seven of which (-7 to -1) precede the catalytic center. Low catalytic activity of Cel7A is the bottleneck and the primary target for improvement. Here it is shown for the first time that, in spite of much lower apparent kcat of HjCel7A at the hydrolysis of β-1,4-glucosidic linkages in the fluorogenic cellotetra- and -pentaose compared to the structurally related endoglucanase I (HjCel7B), the specificity constants (catalytic efficiency) kcat /Km for both enzymes are almost equal in these reactions. The observed activity difference appears from strong nonproductive substrate binding by HjCel7A, particularly significant for MU-β-cellotetraose (MUG4 ). Interaction of substrates with the subsites -6 and -5 proximal to the nonconserved Gln101 residue in HjCel7A decreases Km,ap by >1500 times. HjCel7A can be nonproductively bound onto cellulose surface with Kd ≈2-9 nM via CBM and CD that captures six terminal glucose units of cellulose chain. Decomposition of this nonproductive complex can determine the rate of cellulose conversion. MUG4 is a promising substrate to select active cellobiohydrolase I variants with reduced nonproductive substrate binding.
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Affiliation(s)
- Mikhail L Rabinovich
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
| | - Maria S Melnik
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
| | - Mikhail L Herner
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
| | - Yakov V Voznyi
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia
| | - Lilia G Vasilchenko
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
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11
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Silveira RL, Skaf MS. Concerted motions and large-scale structural fluctuations of Trichoderma reesei Cel7A cellobiohydrolase. Phys Chem Chem Phys 2018; 20:7498-7507. [PMID: 29488531 DOI: 10.1039/c8cp00101d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Cellobiohydrolases (CBHs) are key enzymes for the saccharification of cellulose and play major roles in industrial settings for biofuel production. The catalytic core domain of these enzymes exhibits a long and narrow binding tunnel capable of binding glucan chains from crystalline cellulose and processively hydrolyze them. The binding cleft is topped by a set of loops, which are believed to play key roles in substrate binding and cleavage processivity. Here, we present an analysis of the loop motions of the Trichoderma reesei Cel7A catalytic core domain (TrCel7A) using conventional and accelerated molecular dynamics simulations. We observe that the loops exhibit highly coupled fluctuations and cannot move independently of each other. In the absence of a substrate, the characteristic large amplitude dynamics of TrCel7A consists of breathing motions, where the loops undergo open-and-close fluctuations. Upon substrate binding, the open-close fluctuations of the loops are quenched and one of the loops moves parallel to the binding site, possibly to allow processive motion along the glucan chain. Using microsecond accelerated molecular dynamics, we observe large-scale fluctuations of the loops (up to 37 Å) and the entire exposure of the TrCel7A binding site in the absence of the substrate, resembling an endoglucanase. These results suggest that the initial CBH-substrate contact and substrate recognition by the enzyme are similar to that of endoglucanases and, once bound to the substrate, the loops remain closed for proper enzymatic activity.
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Affiliation(s)
- Rodrigo L Silveira
- Institute of Chemistry, University of Campinas, Cx. P. 6154, Campinas, 13084-862, SP, Brazil.
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12
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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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13
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Kadowaki MAS, Higasi P, de Godoy MO, Prade RA, Polikarpov I. Biochemical and structural insights into a thermostable cellobiohydrolase from Myceliophthora thermophila. FEBS J 2018; 285:559-579. [PMID: 29222836 DOI: 10.1111/febs.14356] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/20/2017] [Accepted: 12/05/2017] [Indexed: 12/27/2022]
Abstract
Cellobiohydrolases hydrolyze cellulose, a linear polymer with glucose monomers linked exclusively by β-1,4 glycosidic linkages. The widespread hydrogen bonding network tethers individual cellulose polymers forming crystalline cellulose, which prevent the access of hydrolytic enzymes and water molecules. The most abundant enzyme secreted by Myceliophthora thermophila M77 in response to the presence of biomass is the cellobiohydrolase MtCel7A, which is composed by a GH7-catalytic domain (CD), a linker, and a CBM1-type carbohydrate-binding module. GH7 cellobiohydrolases have been studied before, and structural models have been proposed. However, currently available GH7 crystal structures only define separate catalytic domains and/or cellulose-binding modules and do not include the full-length structures that are involved in shaping the catalytic mode of operation. In this study, we determined the 3D structure of catalytic domain using X-ray crystallography and retrieved the full-length enzyme envelope via small-angle X-ray scattering (SAXS) technique. The SAXS data reveal a tadpole-like molecular shape with a rigid linker connecting the CD and CBM. Our biochemical studies show that MtCel7A has higher catalytic efficiency and thermostability as well as lower processivity when compared to the well-studied TrCel7A from Trichoderma reesei. Based on a comparison of the crystallographic structures of CDs and their molecular dynamic simulations, we demonstrate that MtCel7A has considerably higher flexibility than TrCel7A. In particular, loops that cover the active site are more flexible and undergo higher conformational fluctuations, which might account for decreased processivity and enhanced enzymatic efficiency. Our statistical coupling analysis suggests co-evolution of amino acid clusters comprising the catalytic site of MtCel7A, which correlate with the steps in the catalytic cycle of the enzyme. DATABASE The atomic coordinates and structural factors of MtCel7A have been deposited in the Protein Data Bank with accession number 5W11.
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Affiliation(s)
| | - Paula Higasi
- São Carlos Institute of Physics, University of São Paulo, Brazil
| | | | - Rolf A Prade
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, Brazil
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14
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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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16
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Goedegebuur F, Dankmeyer L, Gualfetti P, Karkehabadi S, Hansson H, Jana S, Huynh V, Kelemen BR, Kruithof P, Larenas EA, Teunissen PJM, Ståhlberg J, Payne CM, Mitchinson C, Sandgren M. Improving the thermal stability of cellobiohydrolase Cel7A from Hypocrea jecorina by directed evolution. J Biol Chem 2017; 292:17418-17430. [PMID: 28860192 DOI: 10.1074/jbc.m117.803270] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/24/2017] [Indexed: 11/06/2022] Open
Abstract
Secreted mixtures of Hypocrea jecorina cellulases are able to efficiently degrade cellulosic biomass to fermentable sugars at large, commercially relevant scales. H. jecorina Cel7A, cellobiohydrolase I, from glycoside hydrolase family 7, is the workhorse enzyme of the process. However, the thermal stability of Cel7A limits its use to processes where temperatures are no higher than 50 °C. Enhanced thermal stability is desirable to enable the use of higher processing temperatures and to improve the economic feasibility of industrial biomass conversion. Here, we enhanced the thermal stability of Cel7A through directed evolution. Sites with increased thermal stability properties were combined, and a Cel7A variant (FCA398) was obtained, which exhibited a 10.4 °C increase in Tm and a 44-fold greater half-life compared with the wild-type enzyme. This Cel7A variant contains 18 mutated sites and is active under application conditions up to at least 75 °C. The X-ray crystal structure of the catalytic domain was determined at 2.1 Å resolution and showed that the effects of the mutations are local and do not introduce major backbone conformational changes. Molecular dynamics simulations revealed that the catalytic domain of wild-type Cel7A and the FCA398 variant exhibit similar behavior at 300 K, whereas at elevated temperature (475 and 525 K), the FCA398 variant fluctuates less and maintains more native contacts over time. Combining the structural and dynamic investigations, rationales were developed for the stabilizing effect at many of the mutated sites.
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Affiliation(s)
- Frits Goedegebuur
- From DuPont Industrial Biosciences, Archimedesweg 30, Leiden 2333CN, The Netherlands,
| | - Lydia Dankmeyer
- From DuPont Industrial Biosciences, Archimedesweg 30, Leiden 2333CN, The Netherlands
| | | | - Saeid Karkehabadi
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, Uppsala SE-75007, Sweden, and
| | - Henrik Hansson
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, Uppsala SE-75007, Sweden, and
| | - Suvamay Jana
- the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506
| | - Vicky Huynh
- DuPont Industrial Biosciences, Palo Alto, California 94304
| | | | - Paulien Kruithof
- From DuPont Industrial Biosciences, Archimedesweg 30, Leiden 2333CN, The Netherlands
| | | | | | - Jerry Ståhlberg
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, Uppsala SE-75007, Sweden, and
| | - Christina M Payne
- the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506
| | | | - Mats Sandgren
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, Uppsala SE-75007, Sweden, and
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Ogunmolu FE, Jagadeesha NBK, Kumar R, Kumar P, Gupta D, Yazdani SS. Comparative insights into the saccharification potentials of a relatively unexplored but robust Penicillium funiculosum glycoside hydrolase 7 cellobiohydrolase. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:71. [PMID: 28344646 PMCID: PMC5360062 DOI: 10.1186/s13068-017-0752-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 03/09/2017] [Indexed: 05/08/2023]
Abstract
BACKGROUND GH7 cellobiohydrolases (CBH1) are vital for the breakdown of cellulose. We had previously observed the enzyme as the most dominant protein in the active cellulose-hydrolyzing secretome of the hypercellulolytic ascomycete-Penicillium funiculosum (NCIM1228). To understand its contributions to cellulosic biomass saccharification in comparison with GH7 cellobiohydrolase from the industrial workhorse-Trichoderma reesei, we natively purified and functionally characterized the only GH7 cellobiohydrolase identified and present in the genome of the fungus. RESULTS There were marginal differences observed in the stability of both enzymes, with P. funiculosum (PfCBH1) showing an optimal thermal midpoint (Tm) of 68 °C at pH 4.4 as against an optimal Tm of 65 °C at pH 4.7 for T. reesei (TrCBH1). Nevertheless, PfCBH1 had an approximate threefold lower binding affinity (Km), an 18-fold higher turnover rate (kcat), a sixfold higher catalytic efficiency as well as a 26-fold higher enzyme-inhibitor complex equilibrium dissociation constant (Ki) than TrCBH1 on p-nitrophenyl-β-d-lactopyranoside (pNPL). Although both enzymes hydrolyzed cellooligomers (G2-G6) and microcrystalline cellulose, releasing cellobiose and glucose as the major products, the propensity was more with PfCBH1. We equally observed this trend during the hydrolysis of pretreated wheat straws in tandem with other core cellulases under the same conditions. Molecular dynamic simulations conducted on a homology model built using the TrCBH1 structure (PDB ID: 8CEL) as a template enabled us to directly examine the effects of substrate and products on the protein dynamics. While the catalytic triads-EXDXXE motifs-were conserved between the two enzymes, subtle variations in regions enclosing the catalytic path were observed, and relations to functionality highlighted. CONCLUSION To the best of our knowledge, this is the first report about a comprehensive and comparative description of CBH1 from hypercellulolytic ascomycete-P. funiculosum NCIM1228, against the backdrop of the same enzyme from the industrial workhorse-T. reesei. Our study reveals PfCBH1 as a viable alternative for CBH1 from T. reesei in industrial cellulase cocktails.
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Affiliation(s)
- Funso Emmanuel Ogunmolu
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067 India
| | - Navya Bhatt Kammachi Jagadeesha
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067 India
| | - Rakesh Kumar
- Translational Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Pawan Kumar
- Translational Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Dinesh Gupta
- Translational Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Syed Shams Yazdani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067 India
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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18
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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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19
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Biochemical and Structural Characterizations of Two Dictyostelium Cellobiohydrolases from the Amoebozoa Kingdom Reveal a High Level of Conservation between Distant Phylogenetic Trees of Life. Appl Environ Microbiol 2016; 82:3395-409. [PMID: 27037126 DOI: 10.1128/aem.00163-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 03/25/2016] [Indexed: 12/26/2022] Open
Abstract
UNLABELLED Glycoside hydrolase family 7 (GH7) cellobiohydrolases (CBHs) are enzymes commonly employed in plant cell wall degradation across eukaryotic kingdoms of life, as they provide significant hydrolytic potential in cellulose turnover. To date, many fungal GH7 CBHs have been examined, yet many questions regarding structure-activity relationships in these important natural and commercial enzymes remain. Here, we present the crystal structures and a biochemical analysis of two GH7 CBHs from social amoeba: Dictyostelium discoideum Cel7A (DdiCel7A) and Dictyostelium purpureum Cel7A (DpuCel7A). DdiCel7A and DpuCel7A natively consist of a catalytic domain and do not exhibit a carbohydrate-binding module (CBM). The structures of DdiCel7A and DpuCel7A, resolved to 2.1 Å and 2.7 Å, respectively, are homologous to those of other GH7 CBHs with an enclosed active-site tunnel. Two primary differences between the Dictyostelium CBHs and the archetypal model GH7 CBH, Trichoderma reesei Cel7A (TreCel7A), occur near the hydrolytic active site and the product-binding sites. To compare the activities of these enzymes with the activity of TreCel7A, the family 1 TreCel7A CBM and linker were added to the C terminus of each of the Dictyostelium enzymes, creating DdiCel7ACBM and DpuCel7ACBM, which were recombinantly expressed in T. reesei DdiCel7ACBM and DpuCel7ACBM hydrolyzed Avicel, pretreated corn stover, and phosphoric acid-swollen cellulose as efficiently as TreCel7A when hydrolysis was compared at their temperature optima. The Ki of cellobiose was significantly higher for DdiCel7ACBM and DpuCel7ACBM than for TreCel7A: 205, 130, and 29 μM, respectively. Taken together, the present study highlights the remarkable degree of conservation of the activity of these key natural and industrial enzymes across quite distant phylogenetic trees of life. IMPORTANCE GH7 CBHs are among the most important cellulolytic enzymes both in nature and for emerging industrial applications for cellulose breakdown. Understanding the diversity of these key industrial enzymes is critical to engineering them for higher levels of activity and greater stability. The present work demonstrates that two GH7 CBHs from social amoeba are surprisingly quite similar in structure and activity to the canonical GH7 CBH from the model biomass-degrading fungus T. reesei when tested under equivalent conditions (with added CBM-linker domains) on an industrially relevant substrate.
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20
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Borisova AS, Eneyskaya EV, Bobrov KS, Jana S, Logachev A, Polev DE, Lapidus AL, Ibatullin FM, Saleem U, Sandgren M, Payne CM, Kulminskaya AA, Ståhlberg J. Sequencing, biochemical characterization, crystal structure and molecular dynamics of cellobiohydrolase Cel7A from
Geotrichum candidum
3C. FEBS J 2015; 282:4515-37. [DOI: 10.1111/febs.13509] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/13/2015] [Accepted: 09/04/2015] [Indexed: 01/01/2023]
Affiliation(s)
- Anna S. Borisova
- Department of Chemistry and Biotechnology Swedish University of Agricultural Sciences Uppsala Sweden
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
| | - Elena V. Eneyskaya
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
| | - Kirill S. Bobrov
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
| | - Suvamay Jana
- Department of Chemical and Materials Engineering University of Kentucky Lexington KY USA
| | - Anton Logachev
- Theodosius Dobzhansky Center for Genome Bioinformatics St. Petersburg State University Russia
| | - Dmitrii E. Polev
- Research Resource Centre «Molecular and Cell Technologies» St. Petersburg State University Russia
| | - Alla L. Lapidus
- Centre for Algorithmic Biotechnology St. Petersburg Academic University Russia
| | - Farid M. Ibatullin
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
| | - Umair Saleem
- Department of Chemistry and Biotechnology Swedish University of Agricultural Sciences Uppsala Sweden
| | - Mats Sandgren
- Department of Chemistry and Biotechnology Swedish University of Agricultural Sciences Uppsala Sweden
| | - Christina M. Payne
- Department of Chemical and Materials Engineering University of Kentucky Lexington KY USA
| | - Anna A. Kulminskaya
- National Research Centre «Kurchatov Institute» B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Orlova roscha Russia
- Department of Medical Physics Peter the Great St. Petersburg Polytechnic University Russia
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology Swedish University of Agricultural Sciences Uppsala Sweden
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21
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Song X, Wang Y, Zhang S, Yan S, Li T, Yao L. Characterization of the Dielectric Constant in the Trichoderma reesei Cel7B Active Site. J Chem Inf Model 2015; 55:1369-76. [PMID: 26114648 DOI: 10.1021/acs.jcim.5b00155] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An attempt is made to evaluate the dielectric constant of the Trichoderma reesei Cel7B active site. Through kinetic measurements, the pKa value of the catalytic acid E201 is determined. Mutations (away from E201) with net charge changes are introduced to perturb the E201 pKa. It is shown that the mutation with a +1 charge change (including G225R, G230R, and A335R) decreases the pKa of E201, whereas the mutation with a -1 charge change (including Q149E, A222D, G225D, and G230D) increases the pKa. This effect is consistent with the electrostatic interaction between the changed charge and the E201 side chain. The fitting of the experimental data yields an apparent dielectric constant of 25-80. Molecular dynamics simulations with explicit water molecules indicate that the high solvent accessibility of the active site contributes largely to the high dielectric constant. ONIOM calculations show that high dielectric constant benefits the catalysis through decreasing the energy of the transition state relative to that of the enzyme substrate complex.
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Affiliation(s)
- Xiangfei Song
- †Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266061, China
| | - Yefei Wang
- †Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266061, China
| | - Shujun Zhang
- †Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266061, China
| | - Shihai Yan
- ‡College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong, 266109, China
| | - Tong Li
- †Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266061, China
| | - Lishan Yao
- †Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266061, China
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22
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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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23
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Silveira RL, Skaf MS. Molecular Dynamics Simulations of Family 7 Cellobiohydrolase Mutants Aimed at Reducing Product Inhibition. J Phys Chem B 2014; 119:9295-303. [DOI: 10.1021/jp509911m] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Rodrigo L. Silveira
- Institute
of Chemistry, University of Campinas, Cx. P. 6154 Campinas, SP, 13084-862, Brazil
| | - Munir S. Skaf
- Institute
of Chemistry, University of Campinas, Cx. P. 6154 Campinas, SP, 13084-862, Brazil
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24
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Momeni MH, Goedegebuur F, Hansson H, Karkehabadi S, Askarieh G, Mitchinson C, Larenas EA, Ståhlberg J, Sandgren M. Expression, crystal structure and cellulase activity of the thermostable cellobiohydrolase Cel7A from the fungus Humicola grisea var. thermoidea. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:2356-66. [PMID: 25195749 PMCID: PMC4157447 DOI: 10.1107/s1399004714013844] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/13/2014] [Indexed: 11/11/2022]
Abstract
Glycoside hydrolase family 7 (GH7) cellobiohydrolases (CBHs) play a key role in biomass recycling in nature. They are typically the most abundant enzymes expressed by potent cellulolytic fungi, and are also responsible for the majority of hydrolytic potential in enzyme cocktails for industrial processing of plant biomass. The thermostability of the enzyme is an important parameter for industrial utilization. In this study, Cel7 enzymes from different fungi were expressed in a fungal host and assayed for thermostability, including Hypocrea jecorina Cel7A as a reference. The most stable of the homologues, Humicola grisea var. thermoidea Cel7A, exhibits a 10°C higher melting temperature (T(m) of 72.5°C) and showed a 4-5 times higher initial hydrolysis rate than H. jecorina Cel7A on phosphoric acid-swollen cellulose and showed the best performance of the tested enzymes on pretreated corn stover at elevated temperature (65°C, 24 h). The enzyme shares 57% sequence identity with H. jecorina Cel7A and consists of a GH7 catalytic module connected by a linker to a C-terminal CBM1 carbohydrate-binding module. The crystal structure of the H. grisea var. thermoidea Cel7A catalytic module (1.8 Å resolution; R(work) and R(free) of 0.16 and 0.21, respectively) is similar to those of other GH7 CBHs. The deviations of several loops along the cellulose-binding path between the two molecules in the asymmetric unit indicate higher flexibility than in the less thermostable H. jecorina Cel7A.
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Affiliation(s)
- Majid Haddad Momeni
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Frits Goedegebuur
- DuPont, Industrial Biosciences, Archimedesweg 30, 2333 CN Leiden, The Netherlands
| | - Henrik Hansson
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Saeid Karkehabadi
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Glareh Askarieh
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Colin Mitchinson
- DuPont, Industrial Biosciences, Page Mill Road, Palo Alto, CA 94304, USA
| | - Edmundo A. Larenas
- DuPont, Industrial Biosciences, Page Mill Road, Palo Alto, CA 94304, USA
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Mats Sandgren
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
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25
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Knott BC, Crowley MF, Himmel ME, Ståhlberg J, Beckham GT. Carbohydrate-protein interactions that drive processive polysaccharide translocation in enzymes revealed from a computational study of cellobiohydrolase processivity. J Am Chem Soc 2014; 136:8810-9. [PMID: 24869982 DOI: 10.1021/ja504074g] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Translocation of carbohydrate polymers through protein tunnels and clefts is a ubiquitous biochemical phenomenon in proteins such as polysaccharide synthases, glycoside hydrolases, and carbohydrate-binding modules. Although static snapshots of carbohydrate polymer binding in proteins have long been studied via crystallography and spectroscopy, the molecular details of polysaccharide chain processivity have not been elucidated. Here, we employ simulation to examine how a cellulose chain translocates by a disaccharide unit during the processive cycle of a glycoside hydrolase family 7 cellobiohydrolase. Our results demonstrate that these biologically and industrially important enzymes employ a two-step mechanism for chain threading to form a Michaelis complex and that the free energy barrier to chain threading is significantly lower than the hydrolysis barrier. Taken with previous studies, our findings suggest that the rate-limiting step in enzymatic cellulose degradation is the glycosylation reaction, not chain processivity. Based on the simulations, we find that strong electrostatic interactions with polar residues that are conserved in GH7 cellobiohydrolases, but not in GH7 endoglucanases, at the leading glucosyl ring provide the thermodynamic driving force for polysaccharide chain translocation. Also, we consider the role of aromatic-carbohydrate interactions, which are widespread in carbohydrate-active enzymes and have long been associated with processivity. Our analysis suggests that the primary role for these aromatic residues is to provide tunnel shape and guide the carbohydrate chain to the active site. More broadly, this work elucidates the role of common protein motifs found in carbohydrate-active enzymes that synthesize or depolymerize polysaccharides by chain translocation mechanisms coupled to catalysis.
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Affiliation(s)
- Brandon C Knott
- National Bioenergy Center and ‡Biosciences Center, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
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26
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Bodenheimer AM, Cuneo MJ, Swartz PD, He J, O’Neill HM, Myles DAA, Evans BR, Meilleur F. Crystallization and preliminary X-ray diffraction analysis of Hypocrea jecorina Cel7A in two new crystal forms. Acta Crystallogr F Struct Biol Commun 2014; 70:773-6. [PMID: 24915091 PMCID: PMC4051535 DOI: 10.1107/s2053230x14008851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 04/17/2014] [Indexed: 11/10/2022] Open
Abstract
Cel7A (previously known as cellobiohydrolase I) from Hypocrea jecorina was crystallized in two crystalline forms, neither of which have been previously reported. Both forms co-crystallize under the same crystallization conditions. The first crystal form belonged to space group C2, with unit-cell parameters a=152.5, b=44.9, c=57.6 Å, β=101.2°, and diffracted X-rays to 1.5 Å resolution. The second crystal form belonged to space group P6₃22, with unit-cell parameters a=b≃155, c≃138 Å, and diffracted X-rays to 2.5 Å resolution. The crystals were obtained using full-length Cel7A, which consists of a large 434-residue N-terminal catalytic domain capable of cleaving cellulose, a 27-residue flexible linker and a small 36-residue C-terminal carbohydrate-binding module (CBM). However, a preliminary analysis of the electron-density maps suggests that the linker and CBM are disordered in both crystal forms. Complete refinement and structure analysis are currently in progress.
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Affiliation(s)
- Annette M. Bodenheimer
- Molecular and Structural Biochemistry Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Matthew J. Cuneo
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Paul D. Swartz
- Molecular and Structural Biochemistry Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Junhong He
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Hugh M. O’Neill
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Dean A. A. Myles
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Barbara R. Evans
- Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Flora Meilleur
- Molecular and Structural Biochemistry Department, North Carolina State University, Raleigh, North Carolina, USA
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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27
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Brunecky R, Alahuhta M, Xu Q, Donohoe BS, Crowley MF, Kataeva IA, Yang SJ, Resch MG, Adams MWW, Lunin VV, Himmel ME, Bomble YJ. Response to Comment on "Revealing nature's cellulase diversity: the digestion mechanism of Caldicellulosiruptor bescii CelA". Science 2014; 344:578. [PMID: 24812382 DOI: 10.1126/science.1251701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Gusakov critiques our methodology for comparing the cellulolytic activity of the bacterial cellulase CelA with the fungal cellulase Cel7A. We address his concerns by clarifying some misconceptions, carefully referencing the literature, and justifying our approach to point out that the results from our study still stand.
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Affiliation(s)
- Roman Brunecky
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
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28
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Zhang H, Zhang JL, Sun L, Niu XD, Wang S, Shan YM. Molecular dynamics simulation of the processive endocellulase Cel48F fromClostridium cellulolyticum: a novel “water-control mechanism” in enzymatic hydrolysis of cellulose. J Mol Recognit 2014; 27:438-47. [DOI: 10.1002/jmr.2364] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 01/14/2014] [Accepted: 01/28/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Hao Zhang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| | - Ji-long Zhang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| | - Lu Sun
- Department of Pharmacy, China-Japan Union Hospital; Jilin University; Changchun 130033 China
| | - Xiao-di Niu
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| | - Song Wang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry; Jilin University; Changchun 130023 China
| | - Ya-ming Shan
- College of Life Science; Jilin University; Changchun 130012 China
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29
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Brunecky R, Alahuhta M, Xu Q, Donohoe BS, Crowley MF, Kataeva IA, Yang SJ, Resch MG, Adams MWW, Lunin VV, Himmel ME, Bomble YJ. Revealing Nature's Cellulase Diversity: The Digestion Mechanism of Caldicellulosiruptor bescii CelA. Science 2013; 342:1513-6. [PMID: 24357319 DOI: 10.1126/science.1244273] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Roman Brunecky
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
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30
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Payne CM, Jiang W, Shirts MR, Himmel ME, Crowley MF, Beckham GT. Glycoside Hydrolase Processivity Is Directly Related to Oligosaccharide Binding Free Energy. J Am Chem Soc 2013; 135:18831-9. [DOI: 10.1021/ja407287f] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christina M. Payne
- Department
of Chemical and Materials Engineering and Center for Computational
Sciences, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Wei Jiang
- Argonne
Leadership Computing Facility, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Michael R. Shirts
- Department
of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
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31
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Teugjas H, Väljamäe P. Product inhibition of cellulases studied with 14C-labeled cellulose substrates. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:104. [PMID: 23883520 PMCID: PMC3726336 DOI: 10.1186/1754-6834-6-104] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 07/11/2013] [Indexed: 05/02/2023]
Abstract
BACKGROUND As a green alternative for the production of transportation fuels, the enzymatic hydrolysis of lignocellulose and subsequent fermentation to ethanol are being intensively researched. To be economically feasible, the hydrolysis of lignocellulose must be conducted at a high concentration of solids, which results in high concentrations of hydrolysis end-products, cellobiose and glucose, making the relief of product inhibition of cellulases a major challenge in the process. However, little quantitative information on the product inhibition of individual cellulases acting on cellulose substrates is available because it is experimentally difficult to assess the hydrolysis of the heterogeneous polymeric substrate in the high background of added products. RESULTS The cellobiose and glucose inhibition of thermostable cellulases from Acremonium thermophilum, Thermoascus aurantiacus, and Chaetomium thermophilum acting on uniformly 14C-labeled bacterial cellulose and its derivatives, 14C-bacterial microcrystalline cellulose and 14C-amorphous cellulose, was studied. Cellulases from Trichoderma reesei were used for comparison. The enzymes most sensitive to cellobiose inhibition were glycoside hydrolase (GH) family 7 cellobiohydrolases (CBHs), followed by family 6 CBHs and endoglucanases (EGs). The strength of glucose inhibition followed the same order. The product inhibition of all enzymes was relieved at higher temperatures. The inhibition strength measured for GH7 CBHs with low molecular-weight model substrates did not correlate with that measured with 14C-cellulose substrates. CONCLUSIONS GH7 CBHs are the primary targets for product inhibition of the synergistic hydrolysis of cellulose. The inhibition must be studied on cellulose substrates instead of on low molecular-weight model substrates when selecting enzymes for lignocellulose hydrolysis. The advantages of using higher temperatures are an increase in the catalytic efficiency of enzymes and the relief of product inhibition.
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Affiliation(s)
- Hele Teugjas
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b – 202, Tartu 51010, Estonia
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b – 202, Tartu 51010, Estonia
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32
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Valencia EY, Chambergo FS. Mini-review: Brazilian fungi diversity for biomass degradation. Fungal Genet Biol 2013; 60:9-18. [PMID: 23872076 DOI: 10.1016/j.fgb.2013.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 06/28/2013] [Accepted: 07/08/2013] [Indexed: 01/01/2023]
Abstract
Brazil houses over 10% of the total number of known species on Earth, with a great diversity of plants and fungi. The collection, isolation, identification and conservation of filamentous fungi with relevance to agriculture, pharmaceutical, food and biotechnological industries in Biological Resource Centers (CRBs) is very important to the development of a nation's scientific and technological infrastructure. In Brazil, 36 fungal collections are registered in the database of International Collections. Several federal and state programs have encouraged the formation of a researcher's network in order to study natural resources and the nation's biodiversity. In this context, Brazilian researchers have been on the frontiers of knowledge, investigating the enzymatic systems from native filamentous fungi with potential for biomass degradation and biotechnological application. In this review, we address recent progress in Brazilian fungal research, focusing on the identification and study of fungi and enzymes with potential for biomass degradation and application in bioenergy.
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Affiliation(s)
- Estela Y Valencia
- Departamento de Microbiologia Microbiana, Centro Nacional de Biotecnologia (CSIC), Madrid, Spain.
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33
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Zhang Y, Yan S, Yao L. A Mechanistic Study of Trichoderma reesei Cel7B Catalyzed Glycosidic Bond Cleavage. J Phys Chem B 2013; 117:8714-22. [DOI: 10.1021/jp403999s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Yu Zhang
- Laboratory
of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266061, China
| | - Shihai Yan
- Laboratory
of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266061, China
| | - Lishan Yao
- Laboratory
of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266061, China
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Momeni MH, Payne CM, Hansson H, Mikkelsen NE, Svedberg J, Engström Å, Sandgren M, Beckham GT, Ståhlberg J. Structural, biochemical, and computational characterization of the glycoside hydrolase family 7 cellobiohydrolase of the tree-killing fungus Heterobasidion irregulare. J Biol Chem 2013; 288:5861-72. [PMID: 23303184 DOI: 10.1074/jbc.m112.440891] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Root rot fungi of the Heterobasidion annosum complex are the most damaging pathogens in temperate forests, and the recently sequenced Heterobasidion irregulare genome revealed over 280 carbohydrate-active enzymes. Here, H. irregulare was grown on biomass, and the most abundant protein in the culture filtrate was identified as the only family 7 glycoside hydrolase in the genome, which consists of a single catalytic domain, lacking a linker and carbohydrate-binding module. The enzyme, HirCel7A, was characterized biochemically to determine the optimal conditions for activity. HirCel7A was crystallized and the structure, refined at 1.7 Å resolution, confirms that HirCel7A is a cellobiohydrolase rather than an endoglucanase, with a cellulose-binding tunnel that is more closed than Phanerochaete chrysosporium Cel7D and more open than Hypocrea jecorina Cel7A, suggesting intermediate enzyme properties. Molecular simulations were conducted to ascertain differences in enzyme-ligand interactions, ligand solvation, and loop flexibility between the family 7 glycoside hydrolase cellobiohydrolases from H. irregulare, H. jecorina, and P. chrysosporium. The structural comparisons and simulations suggest significant differences in enzyme-ligand interactions at the tunnel entrance in the -7 to -4 binding sites and suggest that a tyrosine residue at the tunnel entrance of HirCel7A may serve as an additional ligand-binding site. Additionally, the loops over the active site in H. jecorina Cel7A are more closed than loops in the other two enzymes, which has implications for the degree of processivity, endo-initiation, and substrate dissociation. Overall, this study highlights molecular level features important to understanding this biologically and industrially important family of glycoside hydrolases.
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Affiliation(s)
- Majid Haddad Momeni
- Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-751 24 Uppsala, Sweden
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