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Schmitz E, Leontakianakou S, Adlercreutz P, Nordberg Karlsson E, Linares-Pastén JA. Novel Function of CtXyn5A from Acetivibrio thermocellus: Dual Arabinoxylanase and Feruloyl Esterase Activity in the Same Active Site. Chembiochem 2023; 24:e202200667. [PMID: 36449982 PMCID: PMC10107809 DOI: 10.1002/cbic.202200667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 11/30/2022] [Accepted: 11/30/2022] [Indexed: 12/02/2022]
Abstract
Enzymes' uncharacterised side activities can have significant effects on reaction products and yields. Hence, their identification and characterisation are crucial for the development of successful reaction systems. Here, we report the presence of feruloyl esterase activity in CtXyn5A from Acetivibrio thermocellus, besides its well-known arabinoxylanase activity, for the first time. Activity analysis of enzyme variants mutated in the catalytic nucleophile, Glu279, confirmed removal of all activity for E279A and E279L, and increased esterase activity while removing xylanase activity for E279S, thus allowing the proposal that both reaction types are catalysed in the same active site in two subsequential steps. The ferulic acid substituent is cleaved off first, followed by hydrolysis of the xylan backbone. The esterase activity on complex carbohydrates was found to be higher than that of a designated ferulic acid esterase (E-FAERU). Therefore, we conclude that the enzyme exhibits a dual function rather than an esterase side activity.
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Affiliation(s)
- Eva Schmitz
- Biotechnology, Department of Chemistry, Lund University, P.O. Box 124, Lund, 22100, Sweden
| | - Savvina Leontakianakou
- Biotechnology, Department of Chemistry, Lund University, P.O. Box 124, Lund, 22100, Sweden
| | - Patrick Adlercreutz
- Biotechnology, Department of Chemistry, Lund University, P.O. Box 124, Lund, 22100, Sweden
| | - Eva Nordberg Karlsson
- Biotechnology, Department of Chemistry, Lund University, P.O. Box 124, Lund, 22100, Sweden
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Identification of Exoenzymes Secreted by Entomopathogenic Fungus Beauveria pseudobassiana RGM 2184 and Their Effect on the Degradation of Cocoons and Pupae of Quarantine Pest Lobesia botrana. J Fungi (Basel) 2022; 8:jof8101083. [PMID: 36294649 PMCID: PMC9605004 DOI: 10.3390/jof8101083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/29/2022] [Accepted: 10/06/2022] [Indexed: 11/07/2022] Open
Abstract
Beauveria pseudobassiana RGM 2184 has shown 80% maximum efficacy against the pest Lobesia botrana in the autumn and winter seasons. This suggests that the strain possesses an interesting battery of enzymes that are cold-adapted to penetrate the thick and hydrophobic cocoon of L. botrana. In this study, screening of the proteolytic, lipolytic, and chitinolytic activity of enzyme extracts secreted by the RGM 2184 strain was carried out in various culture media. The enzyme extracts with the highest activity were subjected to zymography and mass spectrometry. These analyses allowed the identification of two proteases, two lipases, and three chitinases. Comparative analysis indicated that the degree of similarity between these enzymes was substantially reduced when the highest degree of taxonomic relatedness between RGM 2184 and the entomopathogenic fungus strain was at the family level. These results suggest that there is a wide variety of exoenzymes in entomopathogenic fungi species belonging to the order Hypocreales. On the other hand, exoenzyme extract exposure of cocoons and pupae of L. botrana provoked damage at 10 °C. Additionally, an analysis of the amino acid composition of the RGM 2184 exoenzyme grouped them close to the cold-adapted protein cluster. These results support the use of this strain to control pests in autumn and winter. Additionally, these antecedents can form a scaffold for the future characterization of these exoenzymes along with the optimization of the strain’s biocontrol ability by overexpressing them.
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Akram F, Jabbar Z, Aqeel A, Haq IU, Tariq S, Malik K. A Contemporary Appraisal on Impending Industrial and Agricultural Applications of Thermophilic-Recombinant Chitinolytic Enzymes from Microbial Sources. Mol Biotechnol 2022; 64:1055-1075. [PMID: 35397055 DOI: 10.1007/s12033-022-00486-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 03/25/2022] [Indexed: 01/09/2023]
Abstract
The ability of chitinases to degrade the second most abundant polymer, chitin, into potentially useful chitooligomers and chitin derivatives has not only rendered them fit for chitinous waste management but has also made them important from industrial point of view. At the same time, they have also been recognized to have an imperative role as promising biocontrol agents for controlling plant diseases. As thermostability is an important property for an industrially important enzyme, various bacterial and fungal sources are being exploited to obtain such stable enzymes. These stable enzymes can also play a role in agriculture by maintaining their stability under adverse environmental conditions for longer time duration when used as biocontrol agent. Biotechnology has also played its role in the development of recombinant chitinases with enhanced activity, thermostability, fungicidal and insecticidal activity via recombinant DNA techniques. Furthermore, a relatively new approach of generating pathogen-resistant transgenic plants has opened new ways for sustainable agriculture by minimizing the yield loss of valuable crops and plants. This review focuses on the potential applications of thermostable and recombinant microbial chitinases in industry and agriculture.
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Affiliation(s)
- Fatima Akram
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan.
| | - Zuriat Jabbar
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Amna Aqeel
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Ikram Ul Haq
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan.,Pakistan Academy of Sciences, Islamabad, Pakistan
| | - Shahbaz Tariq
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Kausar Malik
- Centre for Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
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4
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Biswal AK, Hengge NN, Black IM, Atmodjo MA, Mohanty SS, Ryno D, Himmel ME, Azadi P, Bomble YJ, Mohnen D. Composition and yield of non-cellulosic and cellulosic sugars in soluble and particulate fractions during consolidated bioprocessing of poplar biomass by Clostridium thermocellum. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:23. [PMID: 35227303 PMCID: PMC8887089 DOI: 10.1186/s13068-022-02119-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Terrestrial plant biomass is the primary renewable carbon feedstock for enabling transition to a sustainable bioeconomy. Consolidated bioprocessing (CBP) by the cellulolytic thermophile Clostridium thermocellum offers a single step microbial platform for production of biofuels and biochemicals via simultaneous solubilization of carbohydrates from lignocellulosic biomass and conversion to products. Here, solubilization of cell wall cellulosic, hemicellulosic, and pectic polysaccharides in the liquor and solid residues generated during CBP of poplar biomass by C. thermocellum was analyzed. RESULTS The total amount of biomass solubilized in the C. thermocellum DSM1313 fermentation platform was 5.8, 10.3, and 13.7% of milled non-pretreated poplar after 24, 48, and 120 h, respectively. These results demonstrate solubilization of 24% cellulose and 17% non-cellulosic sugars after 120 h, consistent with prior reports. The net solubilization of non-cellulosic sugars by C. thermocellum (after correcting for the uninoculated control fermentations) was 13 to 36% of arabinose (Ara), xylose (Xyl), galactose (Gal), mannose (Man), and glucose (Glc); and 15% and 3% of fucose and glucuronic acid, respectively. No rhamnose was solubilized and 71% of the galacturonic acid (GalA) was solubilized. These results indicate that C. thermocellum may be selective for the types and/or rate of solubilization of the non-cellulosic wall polymers. Xyl, Man, and Glc were found to accumulate in the fermentation liquor at levels greater than in uninoculated control fermentations, whereas Ara and Gal did not accumulate, suggesting that C. thermocellum solubilizes both hemicelluloses and pectins but utilizes them differently. After five days of fermentation, the relative amount of Rha in the solid residues increased 21% indicating that the Rha-containing polymer rhamnogalacturonan I (RG-I) was not effectively solubilized by C. thermocellum CBP, a result confirmed by immunoassays. Comparison of the sugars in the liquor versus solid residue showed that C. thermocellum solubilized hemicellulosic xylan and mannan, but did not fully utilize them, solubilized and appeared to utilize pectic homogalacturonan, and did not solubilize RG-I. CONCLUSIONS The significant relative increase in RG-I in poplar solid residues following CBP indicates that C. thermocellum did not solubilize RG-I. These results support the hypothesis that this pectic glycan may be one barrier for efficient solubilization of poplar by C. thermocellum.
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Affiliation(s)
- Ajaya K. Biswal
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA 30602 USA
| | - Neal N. Hengge
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Ian M. Black
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA 30602 USA
| | - Melani A. Atmodjo
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA 30602 USA
| | - Sushree S. Mohanty
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA 30602 USA
| | - David Ryno
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA 30602 USA
| | - Michael E. Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA 30602 USA
| | - Yannick J. Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Debra Mohnen
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA 30602 USA
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Hershko Rimon A, Livnah O, Rozman Grinberg I, Ortiz de Ora L, Yaniv O, Lamed R, Bayer EA, Frolow F, Voronov-Goldman M. Novel clostridial cell-surface hemicellulose-binding CBM3 proteins. Acta Crystallogr F Struct Biol Commun 2021; 77:95-104. [PMID: 33830074 PMCID: PMC8034430 DOI: 10.1107/s2053230x21002764] [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: 01/17/2021] [Accepted: 03/15/2021] [Indexed: 11/10/2022] Open
Abstract
A novel member of the family 3 carbohydrate-binding modules (CBM3s) is encoded by a gene (Cthe_0271) in Clostridium thermocellum which is the most highly expressed gene in the bacterium during its growth on several types of biomass substrates. Surprisingly, CtCBM3-0271 binds to at least two different types of xylan, instead of the common binding of CBM3s to cellulosic substrates. CtCBM3-0271 was crystallized and its three-dimensional structure was solved and refined to a resolution of 1.8 Å. In order to learn more about the role of this type of CBM3, a comparative study with its orthologue from Clostridium clariflavum (encoded by the Clocl_1192 gene) was performed, and the three-dimensional structure of CcCBM3-1192 was determined to 1.6 Å resolution. Carbohydrate binding by CcCBM3-1192 was found to be similar to that by CtCBM3-0271; both exhibited binding to xylan rather than to cellulose. Comparative structural analysis of the two CBM3s provided a clear functional correlation of structure and binding, in which the two CBM3s lack the required number of binding residues in their cellulose-binding strips and thus lack cellulose-binding capabilities. This is an enigma, as CtCBM3-0271 was reported to be a highly expressed protein when the bacterium was grown on cellulose. An additional unexpected finding was that CcCBM3-1192 does not contain the calcium ion that was considered to play a structural stabilizing role in the CBM3 family. Despite the lack of calcium, the five residues that form the calcium-binding site are conserved. The absence of calcium results in conformational changes in two loops of the CcCBM3-1192 structure. In this context, superposition of the non-calcium-binding CcCBM3-1192 with CtCBM3-0271 and other calcium-binding CBM3s reveals a much broader two-loop region in the former compared with CtCBM3-0271.
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Affiliation(s)
- Almog Hershko Rimon
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
- The Daniella Rich Institute for Structural Biology Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Oded Livnah
- The Wolfson Center for Applied and Structural Biology, Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Inna Rozman Grinberg
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
- The Daniella Rich Institute for Structural Biology Research, Tel Aviv University, Ramat Aviv 69978, Israel
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Lizett Ortiz de Ora
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
- Department of Chemistry, University of California, Irvine, CA 92697, USA
| | - Oren Yaniv
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Raphael Lamed
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
- The Daniella Rich Institute for Structural Biology Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Edward A. Bayer
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 760001, Israel
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 8499000, Israel
| | - Felix Frolow
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
- The Daniella Rich Institute for Structural Biology Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Milana Voronov-Goldman
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
- The Daniella Rich Institute for Structural Biology Research, Tel Aviv University, Ramat Aviv 69978, Israel
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6
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Akram F, Akram R, Ikram Ul Haq, Nawaz A, Jabbar Z, Ahmed Z. Biotechnological Eminence of Chitinases: A Focus on Thermophilic Enzyme Sources, Production Strategies and Prominent Applications. Protein Pept Lett 2021; 28:1009-1022. [PMID: 33602064 DOI: 10.2174/0929866528666210218215359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/24/2020] [Accepted: 01/20/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Chitin, the second most abundant polysaccharide in nature, is a constantly valuable and renewable raw material after cellulose. Due to advancement in technology, industrial interest has grown to take advantage of the chitin. OBJECTIVE Now, biomass is being treated with diverse microbial enzymes or cells for the production of desired products under best industrial conditions. Glycosidic bonds in chitin structure are degraded by chitinase enzymes, which are characterized into number of glycoside hydrolase (GHs) families. METHODS Thermophilic microorganisms are remarkable sources of industrially important thermostable enzymes, having ability to survive harsh industrial processing conditions. Thermostable chitinases have an edge over mesophilic chitinases as they can hydrolyse the substrate at relatively high temperatures and exhibit decreased viscosity, significantly reduced contamination risk, thermal and chemical stability and increased solubility. Various methods are employed to purify the enzyme and increase its yield by optimizing various parameters such as temperature, pH, agitation, and by investigating the effect of different chemicals and metal ions etc. Results: Thermostable chitinase enzymes show high specific activity at elevated temperature which distinguish them from mesophiles. Genetic engineering can be used for further improvement of natural chitinases, and unlimited potential for the production of thermophilic chitinases has been highlighted due to advancement in synthetic biological techniques. Thermostable chitinases are then used in different fields such as bioremediation, medicine, agriculture and pharmaceuticals. CONCLUSION This review will provide information about chitinases, biotechnological potential of thermostable enzyme and the methods by which they are being produced and optimized for several industrial applications. Some of the applications of thermostable chitinases have also been briefly described.
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Affiliation(s)
- Fatima Akram
- Institute of Industrial Biotechnology, GC University, Lahore-54000, . Pakistan
| | - Rabia Akram
- Institute of Industrial Biotechnology, GC University, Lahore-54000, . Pakistan
| | - Ikram Ul Haq
- Institute of Industrial Biotechnology, GC University, Lahore-54000, . Pakistan
| | - Ali Nawaz
- Institute of Industrial Biotechnology, GC University, Lahore-54000, . Pakistan
| | - Zuriat Jabbar
- Institute of Industrial Biotechnology, GC University, Lahore-54000, . Pakistan
| | - Zeeshan Ahmed
- Institute of Industrial Biotechnology, GC University, Lahore-54000, . Pakistan
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7
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Lee ME, Shin SK, Oh JJ, Hwang DH, Ko YJ, Hyeon JE, Han SO. Enzymatic production of sugar from fungi and fungi-infected lignocellulosic biomass by a new cellulosomal enzyme harboring N-acetyl-β-d-glucosaminidase activity. BIORESOURCE TECHNOLOGY 2021; 319:124242. [PMID: 33254465 DOI: 10.1016/j.biortech.2020.124242] [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: 09/09/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 06/12/2023]
Abstract
Cellulosomes are scaffold proteins displaying enzymes on the cell wall to efficiently obtain nutrient sources. CcGlcNAcase is a novel cellulosomal component. Based on sequence analysis, CcGlcNAcase was predicted to be a chitinolytic enzyme based on high homology with the discoidin domain-containing protein and chitobiase/ β-hexosaminidase C terminal domain. CcGlcNAcase expression was notably increased when chitin was present. CcGlcNAcase produced N-acetyl-d-glucosamine from various lengths of N-acetyl-d-glucosamine. CcGlcNAcase bound to chitin (89%) and fungi (54.10%), whereas CcGlcNAcase exhibited a low binding ability to cellulose and xylan. CcGlcNAcase hydrolyzed fungi, yielding maximum 3.90 g/L N-acetyl-d-glucosamine. CcGlcNAcase enhanced cellulase toward fungi-infected lignocellulosic biomass, yielding 18 mg/L glucose (1.32-fold) and 1.72-fold increased total reducing sugar levels, whereas cellulase alone produced 13 mg/L glucose. Taken together, CcGlcNAcase can be utilized to enhance the degradation of fungi-infected lignocellulosic biomass and exhibits potential applications in the wood and sugar industry.
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Affiliation(s)
- Myeong-Eun Lee
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Sang Kyu Shin
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Jeong-Joo Oh
- Division of Environmental Science & Ecological Engineering, Korea University, Seoul 01133, Republic of Korea
| | - Dong-Hyeok Hwang
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Young Jin Ko
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Jeong Eun Hyeon
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea; Department of Food Science and Biotechnology, College of Knowledge-Based Services Engineering, Sungshin Women's University, Seoul 01133, Republic of Korea; Department of Food and Nutrition, College of Health & Wellness, Sungshin Women's University, Seoul 01133, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea.
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8
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Mathew GM, Madhavan A, Arun KB, Sindhu R, Binod P, Singhania RR, Sukumaran RK, Pandey A. Thermophilic Chitinases: Structural, Functional and Engineering Attributes for Industrial Applications. Appl Biochem Biotechnol 2020; 193:142-164. [PMID: 32827066 DOI: 10.1007/s12010-020-03416-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 08/12/2020] [Indexed: 02/07/2023]
Abstract
Chitin is the second most widely found natural polymer next to cellulose. Chitinases degrade the insoluble chitin to bioactive chitooligomers and monomers for various industrial applications. Based on their function, these enzymes act as biocontrol agents against pathogenic fungi and invasive pests compared with conventional chemical fungicides and insecticides. They have other functional roles in shellfish waste management, fungal protoplast generation, and Single-Cell Protein production. Among the chitinases, thermophilic and thermostable chitinases are gaining popularity in recent years, as they can withstand high temperatures and maintain the enzyme stability for longer periods. Not all chitinases are thermostable; hence, tailor-made thermophilic chitinases are designed to enhance their thermostability by direct evolution, genetic engineering involving mutagenesis, and proteomics approach. Although research has been done extensively on cloning and expression of thermophilic chitinase genes, there are only few papers discussing on the mechanism of chitin degradation using thermophiles. The current review discusses the sources of thermophilic chitinases, improvement of protein stability by gene manipulation, metagenomics approaches, chitin degradation mechanism in thermophiles, and their prospective applications for industrial, agricultural, and pharmaceutical purposes.
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Affiliation(s)
- Gincy M Mathew
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum, 695 019, India
| | - Aravind Madhavan
- Rajiv Gandhi Center for Biotechnology, Jagathy, Thiruvananthapuram, 695 014, India
| | - K B Arun
- Rajiv Gandhi Center for Biotechnology, Jagathy, Thiruvananthapuram, 695 014, India
| | - Raveendran Sindhu
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum, 695 019, India
| | - Parameswaran Binod
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum, 695 019, India
| | | | - Rajeev K Sukumaran
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum, 695 019, India
| | - Ashok Pandey
- Center for Innovation and Translational Research, CSIR - Indian Institute of Toxicology Research, Lucknow, 226 001, India.
- Frontier Research Lab, Yonsei University, Seoul, South Korea.
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9
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Wang Y, Leng L, Islam MK, Liu F, Lin CSK, Leu SY. Substrate-Related Factors Affecting Cellulosome-Induced Hydrolysis for Lignocellulose Valorization. Int J Mol Sci 2019; 20:ijms20133354. [PMID: 31288425 PMCID: PMC6651384 DOI: 10.3390/ijms20133354] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/30/2019] [Accepted: 07/03/2019] [Indexed: 11/22/2022] Open
Abstract
Cellulosomes are an extracellular supramolecular multienzyme complex that can efficiently degrade cellulose and hemicelluloses in plant cell walls. The structural and unique subunit arrangement of cellulosomes can promote its adhesion to the insoluble substrates, thus providing individual microbial cells with a direct competence in the utilization of cellulosic biomass. Significant progress has been achieved in revealing the structures and functions of cellulosomes, but a knowledge gap still exists in understanding the interaction between cellulosome and lignocellulosic substrate for those derived from biorefinery pretreatment of agricultural crops. The cellulosomic saccharification of lignocellulose is affected by various substrate-related physical and chemical factors, including native (untreated) wood lignin content, the extent of lignin and xylan removal by pretreatment, lignin structure, substrate size, and of course substrate pore surface area or substrate accessibility to cellulose. Herein, we summarize the cellulosome structure, substrate-related factors, and regulatory mechanisms in the host cells. We discuss the latest advances in specific strategies of cellulosome-induced hydrolysis, which can function in the reaction kinetics and the overall progress of biorefineries based on lignocellulosic feedstocks.
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Affiliation(s)
- Ying Wang
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Ling Leng
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan
| | - Md Khairul Islam
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Fanghua Liu
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
| | - Carol Sze Ki Lin
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Shao-Yuan Leu
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
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10
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Leis B, Held C, Andreeßen B, Liebl W, Graubner S, Schulte LP, Schwarz WH, Zverlov VV. Optimizing the composition of a synthetic cellulosome complex for the hydrolysis of softwood pulp: identification of the enzymatic core functions and biochemical complex characterization. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:220. [PMID: 30116297 PMCID: PMC6083626 DOI: 10.1186/s13068-018-1220-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/31/2018] [Indexed: 05/30/2023]
Abstract
BACKGROUND The development of efficient cellulase blends is a key factor for cost-effectively valorizing biomass in a new bio-economy. Today, the enzymatic hydrolysis of plant-derived polysaccharides is mainly accomplished with fungal cellulases, whereas potentially equally effective cellulose-degrading systems from bacteria have not been developed. Particularly, a thermostable multi-enzyme cellulase complex, the cellulosome from the anaerobic cellulolytic bacterium Clostridium thermocellum is promising of being applied as cellulolytic nano-machinery for the production of fermentable sugars from cellulosic biomass. RESULTS In this study, 60 cellulosomal components were recombinantly produced in E. coli and systematically permuted in synthetic complexes to study the function-activity relationship of all available enzymes on Kraft pulp from pine wood as the substrate. Starting from a basic exo/endoglucanase complex, we were able to identify additional functional classes such as mannanase and xylanase for optimal activity on the substrate. Based on these results, we predicted a synthetic cellulosome complex consisting of seven single components (including the scaffoldin protein and a β-glucosidase) and characterized it biochemically. We obtained a highly thermostable complex with optimal activity around 60-65 °C and an optimal pH in agreement with the optimum of the native cellulosome (pH 5.8). Remarkably, a fully synthetic complex containing 47 single cellulosomal components showed comparable activity with a commercially available fungal enzyme cocktail on the softwood pulp substrate. CONCLUSIONS Our results show that synthetic bacterial multi-enzyme complexes based on the cellulosome of C. thermocellum can be applied as a versatile platform for the quick adaptation and efficient degradation of a substrate of interest.
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Affiliation(s)
- Benedikt Leis
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
- Present Address: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Winchester Str. 2, 35394 Gießen, Germany
| | - Claudia Held
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Björn Andreeßen
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Wolfgang Liebl
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Sigrid Graubner
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Louis-Philipp Schulte
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Wolfgang H. Schwarz
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Vladimir V. Zverlov
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
- Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq. 2, Moscow, 123182 Russia
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11
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Enzymatic diversity of the Clostridium thermocellum cellulosome is crucial for the degradation of crystalline cellulose and plant biomass. Sci Rep 2016; 6:35709. [PMID: 27759119 PMCID: PMC5069625 DOI: 10.1038/srep35709] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 10/03/2016] [Indexed: 01/18/2023] Open
Abstract
The cellulosome is a supramolecular multienzyme complex comprised of a wide variety of polysaccharide-degrading enzymes and scaffold proteins. The cellulosomal enzymes that bind to the scaffold proteins synergistically degrade crystalline cellulose. Here, we report in vitro reconstitution of the Clostridium thermocellum cellulosome from 40 cellulosomal components and the full-length scaffoldin protein that binds to nine enzyme molecules. These components were each synthesized using a wheat germ cell-free protein synthesis system and purified. Cellulosome complexes were reconstituted from 3, 12, 30, and 40 components based on their contents in the native cellulosome. The activity of the enzyme-saturated complex indicated that greater enzymatic variety generated more synergy for the degradation of crystalline cellulose and delignified rice straw. Surprisingly, a less complete enzyme complex displaying fewer than nine enzyme molecules was more efficient for the degradation of delignified rice straw than the enzyme-saturated complex, despite the fact that the enzyme-saturated complex exhibited maximum synergy for the degradation of crystalline cellulose. These results suggest that greater enzymatic diversity of the cellulosome is crucial for the degradation of crystalline cellulose and plant biomass, and that efficient degradation of different substrates by the cellulosome requires not only a different enzymatic composition, but also different cellulosome structures.
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12
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Decoding Biomass-Sensing Regulons of Clostridium thermocellum Alternative Sigma-I Factors in a Heterologous Bacillus subtilis Host System. PLoS One 2016; 11:e0146316. [PMID: 26731480 PMCID: PMC4711584 DOI: 10.1371/journal.pone.0146316] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/15/2015] [Indexed: 11/25/2022] Open
Abstract
The Gram-positive, anaerobic, cellulolytic, thermophile Clostridium (Ruminiclostridium) thermocellum secretes a multi-enzyme system called the cellulosome to solubilize plant cell wall polysaccharides. During the saccharolytic process, the enzymatic composition of the cellulosome is modulated according to the type of polysaccharide(s) present in the environment. C. thermocellum has a set of eight alternative RNA polymerase sigma (σ) factors that are activated in response to extracellular polysaccharides and share sequence similarity to the Bacillus subtilis σI factor. The aim of the present work was to demonstrate whether individual C. thermocellum σI-like factors regulate specific cellulosomal genes, focusing on C. thermocellum σI6 and σI3 factors. To search for putative σI6- and σI3-dependent promoters, bioinformatic analysis of the upstream regions of the cellulosomal genes was performed. Because of the limited genetic tools available for C. thermocellum, the functionality of the predicted σI6- and σI3-dependent promoters was studied in B. subtilis as a heterologous host. This system enabled observation of the activation of 10 predicted σI6-dependent promoters associated with the C. thermocellum genes: sigI6 (itself, Clo1313_2778), xyn11B (Clo1313_0522), xyn10D (Clo1313_0177), xyn10Z (Clo1313_2635), xyn10Y (Clo1313_1305), cel9V (Clo1313_0349), cseP (Clo1313_2188), sigI1 (Clo1313_2174), cipA (Clo1313_0627), and rsgI5 (Clo1313_0985). Additionally, we observed the activation of 4 predicted σI3-dependent promoters associated with the C. thermocellum genes: sigI3 (itself, Clo1313_1911), pl11 (Clo1313_1983), ce12 (Clo1313_0693) and cipA. Our results suggest possible regulons of σI6 and σI3 in C. thermocellum, as well as the σI6 and σI3 promoter consensus sequences. The proposed -35 and -10 promoter consensus elements of σI6 are CNNAAA and CGAA, respectively. Additionally, a less conserved CGA sequence next to the C in the -35 element and a highly conserved AT sequence three bases downstream of the -10 element were also identified as important nucleotides for promoter recognition. Regarding σI3, the proposed -35 and -10 promoter consensus elements are CCCYYAAA and CGWA, respectively. The present study provides new clues for understanding these recently discovered alternative σI factors.
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13
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Chakraborty S, Fernandes VO, Dias FMV, Prates JAM, Ferreira LMA, Fontes CMGA, Goyal A, Centeno MSJ. Role of pectinolytic enzymes identified in Clostridium thermocellum cellulosome. PLoS One 2015; 10:e0116787. [PMID: 25658912 PMCID: PMC4319962 DOI: 10.1371/journal.pone.0116787] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 12/09/2014] [Indexed: 11/30/2022] Open
Abstract
The cloning, expression and characterization of three cellulosomal pectinolytic enzymes viz., two variants of PL1 (PL1A and PL1B) and PL9 from Clostridium thermocellum was carried out. The comparison of the primary sequences of PL1A, PL1B and PL9 revealed that these proteins displayed considerable sequence similarities with family 1 and 9 polysaccharide lyases, respectively. PL1A, PL1B and PL9 are the putative catalytic domains of protein sequence ABN54148.1 and ABN53381.1 respectively. These two protein sequences also contain putative carbohydrate binding module (CBM) and type-I dockerin. The associated putative CBM of PL1A showed strong homology with family 6 CBMs while those of PL1B and PL9 showed homology with family 35 CBMs. Recombinant derivatives of these three enzymes showed molecular masses of approximately 34 kDa, 40 kDa and 32 kDa for PL1A, PL1B and PL9, respectively. PL1A, PL1B and PL9 displayed high activity toward polygalacturonic acid and pectin (up to 55% methyl-esterified) from citrus fruits. However, PL1B showed relatively higher activity towards 55% and 85% methyl-esterified pectin (citrus). PL1A and PL9 showed higher activity on rhamnogalacturonan than PL1B. Both PL1A and PL9 displayed maximum activity at pH 8.5 with optimum temperature of 50°C and 60°C respectively. PL1B achieved highest activity at pH 9.8, under an optimum temperature of 50°C. PL1A, PL1B and PL9 all produced two or more unsaturated galacturonates from pectic substrates as displayed by TLC analysis confirming that they are endo-pectate lyase belonging to family 1 and 9, respectively. This report reveals that pectinolytic activity displayed by Clostridium thermocellum cellulosome is coordinated by a sub-set of at least three multi-modular enzymes.
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Affiliation(s)
- Soumyadeep Chakraborty
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Vania O. Fernandes
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Fernando M. V. Dias
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Jose A. M. Prates
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Luis M. A. Ferreira
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | | | - Arun Goyal
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
- * E-mail: (AG); (MSJC)
| | - Maria S. J. Centeno
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
- * E-mail: (AG); (MSJC)
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14
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Tolonen AC, Cerisy T, El-Sayyed H, Boutard M, Salanoubat M, Church GM. Fungal lysis by a soil bacterium fermenting cellulose. Environ Microbiol 2014; 17:2618-27. [PMID: 24798076 DOI: 10.1111/1462-2920.12495] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 04/26/2014] [Indexed: 11/28/2022]
Abstract
Recycling of plant biomass by a community of bacteria and fungi is fundamental to carbon flow in terrestrial ecosystems. Here we report how the plant fermenting, soil bacterium Clostridium phytofermentans enhances growth on cellulose by simultaneously lysing and consuming model fungi from soil. We investigate the mechanism of fungal lysis to show that among the dozens of different glycoside hydrolases C. phytofermentans secretes on cellulose, the most highly expressed enzymes degrade fungi rather than plant substrates. These enzymes, the GH18 Cphy1799 and Cphy1800, synergize to hydrolyse chitin, a main component of the fungal cell wall. Purified enzymes inhibit fungal growth and mutants lacking either GH18 grow normally on cellulose and other plant substrates, but have a reduced ability to hydrolyse chitinous substrates and fungal hyphae. Thus, C. phytofermentans boosts growth on cellulose by lysing fungi with its most highly expressed hydrolases, highlighting the importance of fungal interactions to the ecology of cellulolytic bacteria.
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Affiliation(s)
- Andrew C Tolonen
- CEA, DSV, IG, Genoscope, Évry, France.,CNRS-UMR8030, Évry, France.,Université d'Évry Val d'Essonne, Évry, France
| | - Tristan Cerisy
- CEA, DSV, IG, Genoscope, Évry, France.,CNRS-UMR8030, Évry, France.,Université d'Évry Val d'Essonne, Évry, France
| | - Hafez El-Sayyed
- CEA, DSV, IG, Genoscope, Évry, France.,CNRS-UMR8030, Évry, France.,Université d'Évry Val d'Essonne, Évry, France
| | | | - Marcel Salanoubat
- CEA, DSV, IG, Genoscope, Évry, France.,CNRS-UMR8030, Évry, France.,Université d'Évry Val d'Essonne, Évry, France
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA, USA
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15
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Blumer-Schuette SE, Brown SD, Sander KB, Bayer EA, Kataeva I, Zurawski JV, Conway JM, Adams MWW, Kelly RM. Thermophilic lignocellulose deconstruction. FEMS Microbiol Rev 2014; 38:393-448. [DOI: 10.1111/1574-6976.12044] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 08/20/2013] [Accepted: 08/28/2013] [Indexed: 11/28/2022] Open
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16
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Draft genome sequence of the cellulolytic Clostridium thermocellum wild-type strain BC1 playing a role in cellulosic biomass degradation. J Biotechnol 2013; 168:62-3. [PMID: 23968723 DOI: 10.1016/j.jbiotec.2013.08.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 08/09/2013] [Indexed: 01/14/2023]
Abstract
The bacterium Clostridium thermocellum BC1, a thermophilic, anaerobic bacterium of the family Clostridiaceae, was isolated from a compost treatment site in Germany. It is able to grow efficiently on cellulose and cellodextrins. The draft genome sequence of C. thermocellum BC1 has been established and provides the genetic basis for application of this microorganism in thermophilic degradation of cellulosic biomass.
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17
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Newcomb M, Millen J, Chen CY, Wu JHD. Co-transcription of the celC gene cluster in Clostridium thermocellum. Appl Microbiol Biotechnol 2011; 90:625-34. [DOI: 10.1007/s00253-011-3121-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 01/04/2011] [Accepted: 01/06/2011] [Indexed: 10/18/2022]
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18
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Raman B, Pan C, Hurst GB, Rodriguez M, McKeown CK, Lankford PK, Samatova NF, Mielenz JR. Impact of pretreated Switchgrass and biomass carbohydrates on Clostridium thermocellum ATCC 27405 cellulosome composition: a quantitative proteomic analysis. PLoS One 2009; 4:e5271. [PMID: 19384422 PMCID: PMC2668762 DOI: 10.1371/journal.pone.0005271] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 02/12/2009] [Indexed: 11/30/2022] Open
Abstract
Background Economic feasibility and sustainability of lignocellulosic ethanol production requires the development of robust microorganisms that can efficiently degrade and convert plant biomass to ethanol. The anaerobic thermophilic bacterium Clostridium thermocellum is a candidate microorganism as it is capable of hydrolyzing cellulose and fermenting the hydrolysis products to ethanol and other metabolites. C. thermocellum achieves efficient cellulose hydrolysis using multiprotein extracellular enzymatic complexes, termed cellulosomes. Methodology/Principal Findings In this study, we used quantitative proteomics (multidimensional LC-MS/MS and 15N-metabolic labeling) to measure relative changes in levels of cellulosomal subunit proteins (per CipA scaffoldin basis) when C. thermocellum ATCC 27405 was grown on a variety of carbon sources [dilute-acid pretreated switchgrass, cellobiose, amorphous cellulose, crystalline cellulose (Avicel) and combinations of crystalline cellulose with pectin or xylan or both]. Cellulosome samples isolated from cultures grown on these carbon sources were compared to 15N labeled cellulosome samples isolated from crystalline cellulose-grown cultures. In total from all samples, proteomic analysis identified 59 dockerin- and 8 cohesin-module containing components, including 16 previously undetected cellulosomal subunits. Many cellulosomal components showed differential protein abundance in the presence of non-cellulose substrates in the growth medium. Cellulosome samples from amorphous cellulose, cellobiose and pretreated switchgrass-grown cultures displayed the most distinct differences in composition as compared to cellulosome samples from crystalline cellulose-grown cultures. While Glycoside Hydrolase Family 9 enzymes showed increased levels in the presence of crystalline cellulose, and pretreated switchgrass, in particular, GH5 enzymes showed increased levels in response to the presence of cellulose in general, amorphous or crystalline. Conclusions/Significance Overall, the quantitative results suggest a coordinated substrate-specific regulation of cellulosomal subunit composition in C. thermocellum to better suit the organism's needs for growth under different conditions. To date, this study provides the most comprehensive comparison of cellulosomal compositional changes in C. thermocellum in response to different carbon sources. Such studies are vital to engineering a strain that is best suited to grow on specific substrates of interest and provide the building blocks for constructing designer cellulosomes with tailored enzyme composition for industrial ethanol production.
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Affiliation(s)
- Babu Raman
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Chongle Pan
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Gregory B. Hurst
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Miguel Rodriguez
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Catherine K. McKeown
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Patricia K. Lankford
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Nagiza F. Samatova
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Department of Computer Science, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Jonathan R. Mielenz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- * E-mail:
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19
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Leisner JJ, Larsen MH, Jørgensen RL, Brøndsted L, Thomsen LE, Ingmer H. Chitin hydrolysis by Listeria spp., including L. monocytogenes. Appl Environ Microbiol 2008; 74:3823-30. [PMID: 18424542 PMCID: PMC2446553 DOI: 10.1128/aem.02701-07] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 04/02/2008] [Indexed: 11/20/2022] Open
Abstract
Listeria spp., including the food-borne pathogen Listeria monocytogenes, are ubiquitous microorganisms in the environment and thus are difficult to exclude from food processing plants. The factors that contribute to their multiplication and survival in nature are not well understood, but the ability to catabolize various carbohydrates is likely to be very important. One major source of carbon and nitrogen in nature is chitin, an insoluble linear beta-1,4-linked polymer of N-acetylglucosamine (GlcNAc). Chitin is found in cell walls of fungi and certain algae, in the cuticles of arthropods, and in shells and radulae of molluscs. In the present study, we demonstrated that L. monocytogenes and other Listeria spp. are able to hydrolyze alpha-chitin. The chitinolytic activity is repressed by the presence of glucose in the medium, suggesting that chitinolytic activity is subjected to catabolite repression. Activity is also regulated by temperature and is higher at 30 degrees C than at 37 degrees C. In L. monocytogenes EGD, chitin hydrolysis depends on genes encoding two chitinases, lmo0105 (chiB) and lmo1883 (chiA), but not on a gene encoding a putative chitin binding protein (lmo2467). The chiB and chiA genes are phylogenetically related to various well-characterized chitinases. The potential biological implications of chitinolytic activity of Listeria are discussed.
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Affiliation(s)
- J J Leisner
- Department of Veterinary Pathobiology, Faculty of Life Sciences, University of Copenhagen, Grønnegårdsvej 15, 1870 Frederiksberg C, Denmark.
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20
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Gold ND, Martin VJJ. Global view of the Clostridium thermocellum cellulosome revealed by quantitative proteomic analysis. J Bacteriol 2007; 189:6787-95. [PMID: 17644599 PMCID: PMC2045192 DOI: 10.1128/jb.00882-07] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
A metabolic isotope-labeling strategy was used in conjunction with nano-liquid chromatography-electrospray ionization mass spectrometry peptide sequencing to assess quantitative alterations in the expression patterns of subunits within cellulosomes of the cellulolytic bacterium Clostridium thermocellum, grown on either cellulose or cellobiose. In total, 41 cellulosomal proteins were detected, including 36 type I dockerin-containing proteins, which count among them all but three of the known docking components and 16 new subunits. All differential expression data were normalized to the scaffoldin CipA such that protein per cellulosome was compared for growth between the two substrates. Proteins that exhibited higher expression in cellulosomes from cellulose-grown cells than in cellobiose-grown cells were the cell surface anchor protein OlpB, exoglucanases CelS and CelK, and the glycoside hydrolase family 9 (GH9) endoglucanase CelJ. Conversely, lower expression in cellulosomes from cells grown on cellulose than on cellobiose was observed for the GH8 endoglucanase CelA; GH5 endoglucanases CelB, CelE, CelG; and hemicellulases XynA, XynC, XynZ, and XghA. GH9 cellulases were the most abundant group of enzymes per CipA when cells were grown on cellulose, while hemicellulases were the most abundant group on cellobiose. The results support the existing theory that expression of scaffoldin-related proteins is coordinately regulated by a catabolite repression type of mechanism, as well as the prior observation that xylanase expression is subject to a growth rate-independent type of regulation. However, concerning transcriptional control of cellulases, which had also been previously shown to be subject to catabolite repression, a novel distinction was observed with respect to endoglucanases.
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Affiliation(s)
- Nicholas D Gold
- Department of Biology, Concordia University, Montréal, Québec, Canada H4B 1R6
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21
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Schwarz WH, Zverlov VV. Protease inhibitors in bacteria: an emerging concept for the regulation of bacterial protein complexes? Mol Microbiol 2006; 60:1323-6. [PMID: 16796670 DOI: 10.1111/j.1365-2958.2006.05181.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Serine protease inhibitors (serpins), the antagonists of serine proteases, were unknown in the bacterial kingdom until recently. Kang et al. in this issue of Molecular Microbiology report the cloning and functional analysis of the three serpin genes from the thermophilic anaerobic bacterium Clostridium thermocellum. Two of the serpins contain a dockerin module for location in the extracellular hydrolytic multienzyme complex, the cellulosome. The susceptibility of cellulosome to proteolytic degradation and the presence of a serine protease in the same complex provoke speculation that protease inhibitor/protease pairs could play hitherto unrecognized roles in protein stability and regulation in bacteria.
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Affiliation(s)
- Wolfgang H Schwarz
- Institute for Microbiology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany.
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22
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Konagaya Y, Tsuchiya C, Sugita H. Purification and characterization of chitinases from Clostridium sp. E-16 isolated from the intestinal tract of the South American sea lion (Otaria flavescens). Lett Appl Microbiol 2006; 43:187-93. [PMID: 16869903 DOI: 10.1111/j.1472-765x.2006.01926.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS This study was undertaken to examine the properties of chitinases purified from Clostridium sp. E-16, an intestinal bacterium of the South American sea lion (Otaria flavescens). We also elucidated the taxonomic status of this bacterium to better understand the role of intestinal anaerobic bacteria in marine animals. METHODS AND RESULTS Two chitinases were purified with ammonium sulfate precipitation, affinity chromatography and preparative electrophoresis from culture supernatant fluid from Clostridium sp. E-16. Molecular mass was estimated to be 77 kDa for chitinase 1 and 98 kDa for chitinase 2 by SDS-PAGE. Optimum pH of both purified chitinases was between 5.0 and 7.0. Chitinase 1 was inhibited with Cu(2+), Fe(2+), Hg(2+) and Zn(2+), while chitinase 2 was inhibited with Fe(2+). Phylogenetic analysis using 16S ribosomal DNA (rDNA) sequences and phenotypic characterization revealed that Clostridium sp. E-16 was closely related to Clostridium baratii. CONCLUSIONS It is likely that chitinases from C. baratii or a C. baratii-like bacterium play an important role in degradation of chitin in the intestinal tract of the South American sea lion and in marine environments. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first report of chitinase purification and characterization from a marine Clostridium strain.
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Affiliation(s)
- Y Konagaya
- Department of Marine Science and Resources, Nihon University, Kanagawa, Japan
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23
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Percival Zhang YH, Himmel ME, Mielenz JR. Outlook for cellulase improvement: screening and selection strategies. Biotechnol Adv 2006; 24:452-81. [PMID: 16690241 DOI: 10.1016/j.biotechadv.2006.03.003] [Citation(s) in RCA: 663] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 03/06/2006] [Accepted: 03/11/2006] [Indexed: 10/24/2022]
Abstract
Cellulose is the most abundant renewable natural biological resource, and the production of biobased products and bioenergy from less costly renewable lignocellulosic materials is important for the sustainable development of human beings. A reduction in cellulase production cost, an improvement in cellulase performance, and an increase in sugar yields are all vital to reduce the processing costs of biorefineries. Improvements in specific cellulase activities for non-complexed cellulase mixtures can be implemented through cellulase engineering based on rational design or directed evolution for each cellulase component enzyme, as well as on the reconstitution of cellulase components. Here, we review quantitative cellulase activity assays using soluble and insoluble substrates, and focus on their advantages and limitations. Because there are no clear relationships between cellulase activities on soluble substrates and those on insoluble substrates, soluble substrates should not be used to screen or select improved cellulases for processing relevant solid substrates, such as plant cell walls. Cellulase improvement strategies based on directed evolution using screening on soluble substrates have been only moderately successful, and have primarily targeted improvement in thermal tolerance. Heterogeneity of insoluble cellulose, unclear dynamic interactions between insoluble substrate and cellulase components, and the complex competitive and/or synergic relationship among cellulase components limit rational design and/or strategies, depending on activity screening approaches. Herein, we hypothesize that continuous culture using insoluble cellulosic substrates could be a powerful selection tool for enriching beneficial cellulase mutants from the large library displayed on the cell surface.
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Affiliation(s)
- Y-H Percival Zhang
- Biological Systems Engineering Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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24
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Zverlov VV, Kellermann J, Schwarz WH. Functional subgenomics of Clostridium thermocellum cellulosomal genes: identification of the major catalytic components in the extracellular complex and detection of three new enzymes. Proteomics 2006; 5:3646-53. [PMID: 16127726 DOI: 10.1002/pmic.200401199] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Clostridium thermocellum produces the most efficient enzyme-complex for the degradation of polysaccharides in biomass, the large extracellular cellulosome. The draft complete genomic sequence of Clostridium thermocellum was screened for open reading frames (ORF) containing cellulosomal dockerin sequences. Seventy-one putative cellulosomal genes were detected. One third of these ORFs may be involved in cellulose hydrolysis. Most of the others showed homology to hemicellulases, pectinases, chitinases, glycosidases or esterases potentially involved in the unwrapping of cellulose fibers. To identify the predominant catalytic components, cellulosomes were purified and the components were separated by an adapted two-dimensional gel electrophoresis technique. The apparent major spots were identified by MALDI-TOF/TOF. Ten of the components were previously known: the structural protein CipA, the endo-glucanases Cel8A, Cel5G, Cel9N, the cellobiohydrolases Cbh9A, Cel9K, Cel48S, the xylanases Xyn10C, Xyn10Z, and the chitinase Chi18A. In addition, three hitherto unknown major components were detected, Cel9R, Xyn10D and Xgh74A. These major components in the cellulosomal particles most probably constitute the essential enzymes for crystalline cellulose hydrolysis.
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Affiliation(s)
- Vladimir V Zverlov
- Institute for Microbiology, Technische Universität München, Freising-Weihenstephan, Germany
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Zverlov VV, Schantz N, Schmitt-Kopplin P, Schwarz WH. Two new major subunits in the cellulosome of Clostridium thermocellum: xyloglucanase Xgh74A and endoxylanase Xyn10D. MICROBIOLOGY-SGM 2005; 151:3395-3401. [PMID: 16207921 DOI: 10.1099/mic.0.28206-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The structure and enzymic activity of xyloglucanase Xgh74A and endoxylanase Xyn10D, components in the cellulosomes of cellulose-grown Clostridium thermocellum, were determined. Xyn10D is a thermostable endo-1,4-beta-xylanase with a module composition identical to Xyn10C (CBM22-GH10-Doc). It hydrolyses xylan and mixed-linkage 1,3-1,4-beta-glucan with a temperature optimum of 80 degrees C. Xyloglucanase Xgh74A contains a catalytic module of GHF74 in addition to a C-terminal dockerin module. It hydrolyses every fourth beta-1,4-glucan bond in the xyloglucan backbone, thus producing decorated cellotetraose units. Its low activity on CMC and lack of activity on amorphous cellulose indicates recognition of the xylosidic side chains present in xyloglucan, which is readily hydrolysed (295 U mg(-1)). The pattern of the hydrolysis products from tamarind xyloglucan resembles that of other GHF74 xyloglucan endoglucanases. The data indicate that Xgh74A and Xyn10D contribute to the in vivo degradation of the hemicelluloses xyloglucan and xylan by the cellulosome of C. thermocellum. Xgh74A is the first xyloglucanase identified in C. thermocellum and the only enzyme in the cellulosome that hydrolyses tamarind xyloglucan.
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Affiliation(s)
- Vladimir V Zverlov
- Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq., 123182 Moscow, Russia
- Research Group Microbial Biotechnology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany
| | - Nicolaus Schantz
- Research Group Microbial Biotechnology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany
| | - Philippe Schmitt-Kopplin
- GSF - National Research Center for Environment and Health, Institute for Ecological Chemistry, Ingolstädter Landstrasse 1, D-85764 Neuherberg, Germany
| | - Wolfgang H Schwarz
- Research Group Microbial Biotechnology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany
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Volkov IY, Lunina NA, Berezina OV, Velikodvorskaya GA, Zverlov VV. Thermoanaerobacter ethanolicus Gene Cluster Containing the α- and β-Galactosidase Genes melA and lacA and Properties of Recombinant LacA. Mol Biol 2005. [DOI: 10.1007/s11008-005-0098-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Biomass conversion to ethanol as a liquid fuel by the thermophilic and anaerobic clostridia offers a potential partial solution to the problem of the world's dependence on petroleum for energy. Coculture of a cellulolytic strain and a saccharolytic strain of Clostridium on agricultural resources, as well as on urban and industrial cellulosic wastes, is a promising approach to an alternate energy source from an economic viewpoint. This review discusses the need for such a process, the cellulases of clostridia, their presence in extracellular complexes or organelles (the cellulosomes), the binding of the cellulosomes to cellulose and to the cell surface, cellulase genetics, regulation of their synthesis, cocultures, ethanol tolerance, and metabolic pathway engineering for maximizing ethanol yield.
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Affiliation(s)
- Arnold L Demain
- Charles A. Dana Research Institute for Scientists Emeriti, HS-330, Drew University, Madison, NJ 07940, USA.
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Schwarz WH, Zverlov VV, Bahl H. Extracellular Glycosyl Hydrolases from Clostridia. ADVANCES IN APPLIED MICROBIOLOGY 2004; 56:215-61. [PMID: 15566981 DOI: 10.1016/s0065-2164(04)56007-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Wolfgang H Schwarz
- Technical University of Munich Institute of Microbiology, D-85350 Freising, Germany
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Bayer EA, Belaich JP, Shoham Y, Lamed R. The cellulosomes: multienzyme machines for degradation of plant cell wall polysaccharides. Annu Rev Microbiol 2004; 58:521-54. [PMID: 15487947 DOI: 10.1146/annurev.micro.57.030502.091022] [Citation(s) in RCA: 597] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The discrete multicomponent, multienzyme cellulosome complex of anaerobic cellulolytic bacteria provides enhanced synergistic activity among the different resident enzymes to efficiently hydrolyze intractable cellulosic and hemicellulosic substrates of the plant cell wall. A pivotal noncatalytic subunit called scaffoldin secures the various enzymatic subunits into the complex via the cohesin-dockerin interaction. The specificity characteristics and tenacious binding between the scaffoldin-based cohesin modules and the enzyme-borne dockerin domains dictate the supramolecular architecture of the cellulosome. The diversity in cellulosome architecture among the known cellulosome-producing bacteria is manifest in the arrangement of their genes in either multiple-scaffoldin or enzyme-linked clusters on the genome. The recently described three-dimensional crystal structure of the cohesin-dockerin heterodimer sheds light on the critical amino acids that contribute to this high-affinity protein-protein interaction. In addition, new information regarding the regulation of cellulosome-related genes, budding genetic tools, and emerging genomics of cellulosome-producing bacteria promises new insight into the assembly and consequences of the multienzyme complex.
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Affiliation(s)
- Edward A Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel.
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Affiliation(s)
- Roy H Doi
- Section of Molecular & Cellular Biology, University of California, Davis, California 95616, USA.
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Han SO, Yukawa H, Inui M, Doi RH. Regulation of expression of cellulosomal cellulase and hemicellulase genes in Clostridium cellulovorans. J Bacteriol 2003; 185:6067-75. [PMID: 14526018 PMCID: PMC225016 DOI: 10.1128/jb.185.20.6067-6075.2003] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The regulation of expression of the genes encoding the cellulases and hemicellulases of Clostridium cellulovorans was studied at the mRNA level with cells grown under various culture conditions. A basic pattern of gene expression and of relative expression levels was obtained from cells grown in media containing poly-, di- or monomeric sugars. The cellulase (cbpA and engE) and hemicellulase (xynA) genes were coordinately expressed in medium containing cellobiose or cellulose. Growth in the presence of cellulose, xylan, and pectin gave rise to abundant expression of most genes (cbpA-exgS, engH, hbpA, manA, engM, engE, xynA, and/or pelA) studied. Moderate expression of cbpA, engH, manA, engE, and xynA was observed when cellobiose or fructose was used as the carbon source. Low levels of mRNA from cbpA, manA, engE, and xynA were observed with cells grown in lactose, mannose, and locust bean gum, and very little or no expression of cbpA, engH, manA, engE, and xynA was detected in glucose-, galactose-, maltose-, and sucrose-grown cells. The cbpA-exgS and engE genes were most frequently expressed under all conditions studied, whereas expression of xynA and pelA was more specifically induced at higher levels in xylan- or pectin-containing medium, respectively. Expression of the genes (cbpA, hbpA, manA, engM, and engE) was not observed in the presence of most soluble di- or monosaccharides such as glucose. These results support the hypotheses that there is coordinate expression of some cellulases and hemicellulases, that a catabolite repression type of mechanism regulates cellulase expression in rapidly growing cells, and that the presence of hemicelluloses has an effect on cellulose utilization by the cell.
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Affiliation(s)
- Sung Ok Han
- Section of Molecular and Cellular Biology, University of California, Davis, California 95616, USA
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Pagès S, Valette O, Abdou L, Bélaïch A, Bélaïch JP. A rhamnogalacturonan lyase in the Clostridium cellulolyticum cellulosome. J Bacteriol 2003; 185:4727-33. [PMID: 12896991 PMCID: PMC166469 DOI: 10.1128/jb.185.16.4727-4733.2003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridium cellulolyticum secretes large multienzymatic complexes with plant cell wall-degrading activities named cellulosomes. Most of the genes encoding cellulosomal components are located in a large gene cluster: cipC-cel48F-cel8C-cel9G-cel9E-orfX-cel9H-cel9J-man5K-cel9M. Downstream of the cel9M gene, a new open reading frame was discovered and named rgl11Y. Amino acid sequence analysis indicates that this gene encodes a multidomain pectinase, Rgl11Y, containing an N-terminal signal sequence, a catalytic domain belonging to family 11 of the polysaccharide lyases, and a C-terminal dockerin domain. The present report describes the biochemical characterization of a recombinant form of Rgl11Y. Rgl11Y cleaves the alpha-L-Rhap-(1-->4)-alpha-D-GalpA glycosidic bond in the backbone of rhamnogalacturonan I (RGI) via a beta-elimination mechanism. Its specific activity on potato pectic galactan and rhamnogalacturonan was found to be 28 and 3.6 IU/mg, respectively, indicating that Rgl11Y requires galactan decoration of the RGI backbone. The optimal pH of Rgl11Y is 8.5 and calcium is required for its activity. Rgl11Y was shown to be incorporated in the C. cellulolyticum cellulosome through a typical cohesin-dockerin interaction. Rgl11Y from C. cellulolyticum is the first cellulosomal rhamnogalacturonase characterized.
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Affiliation(s)
- Sandrine Pagès
- Laboratoire de Bioénergétique et Ingénierie des Protéines, IBSM, Centre National de la Recherche Scientifique, Marseille, France.
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Han SO, Yukawa H, Inui M, Doi RH. Transcription of Clostridium cellulovorans cellulosomal cellulase and hemicellulase genes. J Bacteriol 2003; 185:2520-7. [PMID: 12670976 PMCID: PMC152600 DOI: 10.1128/jb.185.8.2520-2527.2003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transcription of the cellulosomal cellulase/hemicellulase genes of Clostridium cellulovorans has been investigated by Northern blot, reverse transcriptase PCR (RT-PCR), primer extension, and S1 nuclease analysis. Northern hybridizations revealed that the cellulosomal cbpA gene cluster is transcribed as polycistronic mRNAs of 8 and 12 kb. The 8-kb mRNA coded for cbpA and exgS, and the 12-kb mRNA coded for cbpA, exgS, engH, and engK. The sizes of the mRNAs were about 3 kb for engE, 1.8 kb for manA, 2.7 kb for xynA, and 4 kb for pelA, indicating monocistronic transcription of these genes. Primer extension and S1 nuclease analysis of C. cellulovorans RNA showed that the transcriptional start sites of cbpA, engE, manA, and hbpA were located 233, 97, 64, and 61 bp upstream from the first nucleotide of each of the respective translation initiation codons. Alignment of the cbpA, engE, manA, and hbpA promoter regions provided evidence for highly conserved sequences that exhibited strong similarity to the sigma(A) consensus promoter sequences of gram-positive bacteria.
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Affiliation(s)
- Sung Ok Han
- Section of Molecular and Cellular Biology, University of California, Davis, California 95616, USA
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Fuchs KP, Zverlov VV, Velikodvorskaya GA, Lottspeich F, Schwarz WH. Lic16A of Clostridium thermocellum, a non-cellulosomal, highly complex endo-beta-1,3-glucanase bound to the outer cell surface. MICROBIOLOGY (READING, ENGLAND) 2003; 149:1021-1031. [PMID: 12686644 DOI: 10.1099/mic.0.26153-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Clostridium thermocellum produces one major beta-1,3-glucanase. Genomic DNA fragments containing the gene were cloned from two strains, DSM1237(T) (6848 bp) and F7 (9766 bp). Overlapping sequences were 99.9 % identical. The nucleotide sequences contained reading frames for a putative transposase, endo-beta-1,3-1,4-glucanase CelC, a putative transcription regulator of the LacI type, beta-1,3-glucanase Lic16A and a putative membrane protein. The licA genes of both strains encoded an identical protein of 1324 aa with a calculated molecular mass of 148 kDa. Lic16A is an unusually complex protein consisting of a leader peptide, a threefold repeat of an S-layer homologous module (SLH), an unknown module, a catalytic module of glycosyl hydrolase family 16 and a fourfold repeat of a carbohydrate-binding module of family CBM4a. The recombinant Lic16A protein was characterized as an endo-1,3(4)-beta-glucanase with a specific activity of 2680 and 340 U mg(-1) and a K(m) of 0.94 and 2.1 mg ml(-1) towards barley beta-glucan and laminarin, respectively. It was specific for beta-glucans containing beta-1,3-linkages with an optimum temperature of 70 degrees C at pH 6.0. The N-terminal SLH modules were cleaved from the protein as well in Escherichia coli as in C. thermocellum, but nevertheless bound tightly to the rest of the protein. Lic16A was located on the cell surface from which it could be purified after fractionated solubilization. Its inducible production allowed C. thermocellum to grow on beta-1,3- or beta-1,3-1,4-glucan.
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Affiliation(s)
- Klaus-Peter Fuchs
- Research Group Microbial Biotechnology, Technical University of Muenchen, Am Hochanger 4, D-85350 Freising, Germany
| | - Vladimir V Zverlov
- Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq., 123182 Moscow, Russia
| | - Galina A Velikodvorskaya
- Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq., 123182 Moscow, Russia
| | | | - Wolfgang H Schwarz
- Research Group Microbial Biotechnology, Technical University of Muenchen, Am Hochanger 4, D-85350 Freising, Germany
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Zverlov VV, Velikodvorskaya GA, Schwarz WH. Two new cellulosome components encoded downstream of celI in the genome of Clostridium thermocellum: the non-processive endoglucanase CelN and the possibly structural protein CseP. MICROBIOLOGY (READING, ENGLAND) 2003; 149:515-524. [PMID: 12624213 DOI: 10.1099/mic.0.25959-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Clostridium thermocellum produces a great number of extracellular cellulases which are free or cellulosome-bound. The nucleotide sequence of a gene cluster containing the genes celI, celN and cseP was determined from C. thermocellum strain F7. Gene products Cel9I and Cel9N are structurally related enzymes having a glycosyl hydrolase family 9 and a carbohydrate-binding module (CBM3c), but show characteristic differences: Cel9I is a non-cellulosomal protein with an additional CBM (CBM3b), whereas Cel9N contains a cellulosomal dockerin module and no additional CBM. Although Cel9I is a processive endoglucanase, Cel9N is non-processive. Both enzymes hydrolyse phosphoric acid swollen cellulose, but the products of hydrolysis are different. The CseP protein encoded in the gene cluster is the first component attached to the cellulosomal scaffoldin for which no catalytic activity could be detected. It was shown to be present in the cellulosome. Its sequence is homologous to the spore-coat assembly protein CotH of Bacillus subtilis, suggesting a structural role of CseP in the cellulosome.
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Affiliation(s)
- Vladimir V Zverlov
- Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq., 123182 Moscow, Russia
| | - Galina A Velikodvorskaya
- Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq., 123182 Moscow, Russia
| | - Wolfgang H Schwarz
- Research Group Microbial Biotechnology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany
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