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Penneru SK, Saharay M, Krishnan M. CelS-Catalyzed Processive Cellulose Degradation and Cellobiose Extraction for the Production of Bioethanol. J Chem Inf Model 2022; 62:6628-6638. [PMID: 35649216 DOI: 10.1021/acs.jcim.2c00239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Bacterial cellulase enzymes are potent candidates for the efficient production of bioethanol, a promising alternative to fossil fuels, from cellulosic biomass. These enzymes catalyze the breakdown of cellulose in plant biomass into simple sugars and then to bioethanol. In the absence of the enzyme, the cellulosic biomass is recalcitrant to decomposition due to fermentation-resistant lignin and pectin coatings on the cellulose surface, which make them inaccessible for hydrolysis. Cellobiohydrolase CelS is a microbial enzyme that binds to cellulose fiber and efficiently cleaves it into a simple sugar (cellobiose) by a repeated processive chopping mechanism. The two contributing factors to the catalytic reaction rate and the yield of cellobiose are the efficient product expulsion from the product binding site of CelS and the movement of the substrate or cellulose chain into the active site. Despite progress in understanding product expulsion in other cellulases, much remains to be understood about the molecular mechanism of processive action of these enzymes. Here, nonequilibrium molecular dynamics simulations using suitable reaction coordinates are carried out to investigate the energetics and mechanism of the substrate dynamics and product expulsion in CelS. The calculated free energy barrier for the product expulsion is three times lower than that for the processive action indicating that product removal is relatively easier and faster than the sliding of the substrate to the catalytic active site. The water traffic near the active site in response to the product expulsion and the processive action is also explored.
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Affiliation(s)
- Sree Kavya Penneru
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, 1311 Cumberland Avenue, Knoxville, Tennessee 37996-1939, United States
| | - Moumita Saharay
- Department of Systems and Computational Biology, School of Life Sciences, University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad 500046, Telangana, India
| | - Marimuthu Krishnan
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad 500032, India
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Paul M, Mohapatra S, Kumar Das Mohapatra P, Thatoi H. Microbial cellulases - An update towards its surface chemistry, genetic engineering and recovery for its biotechnological potential. BIORESOURCE TECHNOLOGY 2021; 340:125710. [PMID: 34365301 DOI: 10.1016/j.biortech.2021.125710] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
The inherent resistance of lignocellulosic biomass makes it impervious for industrially important enzymes such as cellulases to hydrolyze cellulose. Further, the competitive absorption behavior of lignin and hemicellulose for cellulases, due to their electron-rich surfaces augments the inappropriate utilization of these enzymes. Hence, modification of the surface charge of the cellulases to reduce its non-specific binding to lignin and enhance its affinity for cellulose is an urgent necessity. Further, maintaining the stability of cellulases by the preservation of their secondary structures using immobilization techniques will also play an integral role in its industrial production. In silico approaches for increasing the catalytic activity of cellulase enzymes is also significant along with a range of substrate specificity. In addition, enhanced productivity of cellulases by tailoring the related genes through the process of genetic engineering and higher cellulase recovery after saccharification seems to be promising areas for efficient and large-scale enzyme production concepts.
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Affiliation(s)
- Manish Paul
- Department of Biotechnology, Maharaja Sriram Chandra Bhanja Deo University, Takatpur, Baripada 757003, Odisha, India
| | - Sonali Mohapatra
- Department of Biotechnology, College of Engineering & Technology, Bhubaneswar 751003, Odisha, India
| | - Pradeep Kumar Das Mohapatra
- Department of Microbiology, Raiganj University, Raiganj - 733134, Uttar Dinajpur, West Bengal, India; PAKB Environment Conservation Centre, Raiganj University, Raiganj - 733134, Uttar Dinajpur, West Bengal, India
| | - Hrudayanath Thatoi
- Department of Biotechnology, Maharaja Sriram Chandra Bhanja Deo University, Takatpur, Baripada 757003, Odisha, India.
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3
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Hefferon KL, Cantero‐Tubilla B, Brady J, Wilson D. Aromatic residues surrounding the active site tunnel of TfCel48A influence activity, processivity, and synergistic interactions with other cellulases. Biotechnol Bioeng 2019; 116:2463-2472. [DOI: 10.1002/bit.27086] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/29/2019] [Accepted: 06/02/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Kathleen L. Hefferon
- Department of Cellular and Molecular GeneticsCornell University Ithaca New York
- Department of Food Science and TechnologyCornell University Ithaca New York
| | - Borja Cantero‐Tubilla
- Robert Frederick Smith School of Chemical and Biomolecular EngineeringCornell University Ithaca New York
| | - John Brady
- Department of Food Science and TechnologyCornell University Ithaca New York
| | - David Wilson
- Department of Cellular and Molecular GeneticsCornell University Ithaca New York
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Oleson KR, Sprenger KG, Pfaendtner J, Schwartz DT. Inhibition of the Exoglucanase Cel7A by a Douglas-Fir-Condensed Tannin. J Phys Chem B 2018; 122:8665-8674. [PMID: 30111095 DOI: 10.1021/acs.jpcb.8b05850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Douglas-fir forestry residues are a potential feedstock for saccharification-based biofuels, and condensed tannins are expected to make up ∼3% of the dry mass of this feedstock. Condensed tannins are well-known for their ability to interact with proteins and can bind and inhibit cellulase enzymes used in saccharification. In this study, we use molecular docking and classical molecular dynamics simulations to investigate how a characterized condensed tannin from Douglas-fir bark binds to the exoglucanase Cel7A from Trichoderma reesei. Through looking at the "occupancy" and "residency" of specific amino acid residue-tannin interactions, we find that the binding sites are characterized by many simultaneous tannin-enzyme interactions with the strongest occurring on the catalytic module as opposed to the carbohydrate-binding module. The simulations indicate that tannin inhibition can result from binding at or near the catalytic tunnel's entrance and exit. The analyzed tannin further prefers to bind to loops around the catalytic region and has affinity for aromatic and charged amino acid residues. These insights provide direction for the rational design of tannin-resistant cellulases.
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Affiliation(s)
- Karl R Oleson
- Dept. of Chemical Engineering , University of Washington , Box 351750, Seattle , Washington 98198-1750 , United States
| | - Kayla G Sprenger
- Dept. of Chemical Engineering , University of Washington , Box 351750, Seattle , Washington 98198-1750 , United States.,Institute for Medical Engineering and Science , Massachusetts Institute of Technology , E25-352, Cambridge , Massachusetts 02139 , United States
| | - Jim Pfaendtner
- Dept. of Chemical Engineering , University of Washington , Box 351750, Seattle , Washington 98198-1750 , United States
| | - Daniel T Schwartz
- Dept. of Chemical Engineering , University of Washington , Box 351750, Seattle , Washington 98198-1750 , United States
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5
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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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Schutt TC, Bharadwaj VS, Granum DM, Maupin CM. The impact of active site protonation on substrate ring conformation in Melanocarpus albomyces cellobiohydrolase Cel7B. Phys Chem Chem Phys 2015; 17:16947-58. [DOI: 10.1039/c5cp01801c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding how the protonation state of active site residues impacts the enzyme's structure and substrate conformation is important for improving the efficiency and economic viability of the degradation of cellulosic materials as feedstock for liquid fuel and value-added chemicals.
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Affiliation(s)
- Timothy C. Schutt
- Chemical and Biological Engineering Department
- Colorado School of Mines
- Golden
- USA
| | - Vivek S. Bharadwaj
- Chemical and Biological Engineering Department
- Colorado School of Mines
- Golden
- USA
| | - David M. Granum
- Chemical and Biological Engineering Department
- Colorado School of Mines
- Golden
- USA
| | - C. Mark Maupin
- Chemical and Biological Engineering Department
- Colorado School of Mines
- Golden
- USA
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McMillan AW, Lopez MS, Zhu M, Morse BC, Yeo IC, Amos J, Hull K, Romo D, Glasner ME. Role of an Active Site Loop in the Promiscuous Activities of Amycolatopsis sp. T-1-60 NSAR/OSBS. Biochemistry 2014; 53:4434-44. [DOI: 10.1021/bi500573v] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Andrew W. McMillan
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
| | - Mariana S. Lopez
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
| | | | - Benjamin C. Morse
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
| | - In-Cheol Yeo
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
| | - Jaleesia Amos
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
| | | | | | - Margaret E. Glasner
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, United States
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