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You Y, Kong H, Li C, Gu Z, Ban X, Li Z. Carbohydrate binding modules: Compact yet potent accessories in the specific substrate binding and performance evolution of carbohydrate-active enzymes. Biotechnol Adv 2024; 73:108365. [PMID: 38677391 DOI: 10.1016/j.biotechadv.2024.108365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 04/29/2024]
Abstract
Carbohydrate binding modules (CBMs) are independent non-catalytic domains widely found in carbohydrate-active enzymes (CAZymes), and they play an essential role in the substrate binding process of CAZymes by guiding the appended catalytic modules to the target substrates. Owing to their precise recognition and selective affinity for different substrates, CBMs have received increasing research attention over the past few decades. To date, CBMs from different origins have formed a large number of families that show a variety of substrate types, structural features, and ligand recognition mechanisms. Moreover, through the modification of specific sites of CBMs and the fusion of heterologous CBMs with catalytic domains, improved enzymatic properties and catalytic patterns of numerous CAZymes have been achieved. Based on cutting-edge technologies in computational biology, gene editing, and protein engineering, CBMs as auxiliary components have become portable and efficient tools for the evolution and application of CAZymes. With the aim to provide a theoretical reference for the functional research, rational design, and targeted utilization of novel CBMs in the future, we systematically reviewed the function-related characteristics and potentials of CAZyme-derived CBMs in this review, including substrate recognition and binding mechanisms, non-catalytic contributions to enzyme performances, module modifications, and innovative applications in various fields.
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Affiliation(s)
- Yuxian You
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China
| | - Haocun Kong
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Caiming Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China
| | - Zhengbiao Gu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xiaofeng Ban
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Zhaofeng Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing 214200, China.
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2
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Datta R. Enzymatic degradation of cellulose in soil: A review. Heliyon 2024; 10:e24022. [PMID: 38234915 PMCID: PMC10792583 DOI: 10.1016/j.heliyon.2024.e24022] [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: 10/11/2022] [Revised: 12/13/2023] [Accepted: 01/02/2024] [Indexed: 01/19/2024] Open
Abstract
Cellulose degradation is a critical process in soil ecosystems, playing a vital role in nutrient cycling and organic matter decomposition. Enzymatic degradation of cellulosic biomass is the most sustainable and green method of producing liquid biofuel. It has gained intensive research interest with future perspective as the majority of terrestrial lignocellulose biomass has a great potential to be used as a source of bioenergy. However, the recalcitrant nature of lignocellulose limits its use as a source of energy. Noteworthy enough, enzymatic conversion of cellulose biomass could be a leading future technology. Fungal enzymes play a central role in cellulose degradation. Our understanding of fungal cellulases has substantially redirected in the past few years with the discovery of a new class of enzymes and Cellulosome. Efforts have been made from time to time to develop an economically viable method of cellulose degradation. This review provides insights into the current state of knowledge regarding cellulose degradation in soil and identifies areas where further research is needed.
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Affiliation(s)
- Rahul Datta
- Department of Geology and Pedology, Faculty of Forestry and Wood Technology. Mendel University In Brno, Czech Republic
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3
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Shi Q, Abdel-Hamid AM, Sun Z, Cheng Y, Tu T, Cann I, Yao B, Zhu W. Carbohydrate-binding modules facilitate the enzymatic hydrolysis of lignocellulosic biomass: Releasing reducing sugars and dissociative lignin available for producing biofuels and chemicals. Biotechnol Adv 2023; 65:108126. [PMID: 36921877 DOI: 10.1016/j.biotechadv.2023.108126] [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: 11/18/2022] [Revised: 02/05/2023] [Accepted: 03/08/2023] [Indexed: 03/16/2023]
Abstract
The microbial decomposition and utilization of lignocellulosic biomass present in the plant tissues are driven by a series of carbohydrate active enzymes (CAZymes) acting in concert. As the non-catalytic domains widely found in the modular CAZymes, carbohydrate-binding modules (CBMs) are intimately associated with catalytic domains (CDs) that effect the diverse hydrolytic reactions. The CBMs function as auxiliary components for the recognition, adhesion, and depolymerization of the complex substrate mediated by the associated CDs. Therefore, CBMs are deemed as significant biotools available for enzyme engineering, especially to facilitate the enzymatic hydrolysis of dense and insoluble plant tissues to acquire more fermentable sugars. This review aims at presenting the taxonomies and biological properties of the CBMs currently curated in the CAZy database. The molecular mechanisms that CBMs use in assisting the enzymatic hydrolysis of plant polysaccharides and the regulatory factors of CBM-substrate interactions are outlined in detail. In addition, guidelines for the rational designs of CBM-fused CAZymes are proposed. Furthermore, the potential to harness CBMs for industrial applications, especially in enzymatic pretreatment of the recalcitrant lignocellulose, is evaluated. It is envisaged that the ideas outlined herein will aid in the engineering and production of novel CBM-fused enzymes to facilitate efficient degradation of lignocellulosic biomass to easily fermentable sugars for production of value-added products, including biofuels.
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Affiliation(s)
- Qicheng Shi
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
| | - Ahmed M Abdel-Hamid
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, IL 61801, USA
| | - Zhanying Sun
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanfen Cheng
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China.
| | - Tao Tu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Isaac Cann
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, IL 61801, USA; Department of Animal Science, University of Illinois at Urbana-Champaign, IL 61801, USA; Department of Microbiology, University of Illinois at Urbana-Champaign, IL 61801, USA; Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, IL 61801, USA; Center for East Asian and Pacific Studies, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Bin Yao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Weiyun Zhu
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
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4
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Morais MAB, Paiva JH, Murakami MT. Molecular plasticity of CBM3 ancillary domain leads to conformational changes in the cellulose binding interface. Biochem Biophys Res Commun 2023; 645:71-78. [PMID: 36680939 DOI: 10.1016/j.bbrc.2023.01.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 12/14/2022] [Accepted: 01/10/2023] [Indexed: 01/12/2023]
Abstract
Carbohydrate-binding modules (CBMs) constitute independently folded domains typically associated with carbohydrate-active enzymes (CAZymes). These modules are considered to have a rigid structure without notable conformational changes upon ligand binding, exhibiting a complementary topography in relation to the target carbohydrate. Herein, the high-resolution SAD-solved structure of a CBM from family 3 (BsCBM3) that binds to crystalline cellulose is reported in two crystalline forms. This module showed molecular plasticity with structural differences detected between the two crystalline forms and high RMSD values when compared to NMR ensemble of models. Pronounced structural variances were observed in the cellulose binding interface between NMR and XTAL structures, which were corroborated by molecular dynamics simulations. These findings support that family 3 CBMs targeting to cellulose are rather structurally dynamic modules than rigid entities, suggesting a potential role of conformational changes in polysaccharide recognition and modulation of enzyme activity.
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Affiliation(s)
- Mariana Abrahão Bueno Morais
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Joice Helena Paiva
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Mário Tyago Murakami
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil.
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Ahmad S, Sajjad M, Altayb HN, Sarim Imam S, Alshehri S, Ghoneim MM, Shahid S, Usman Mirza M, Shahid Nadeem M, Kazmi I, Waheed Akhtar M. Engineering processive cellulase of Clostridium thermocellum to divulge the role of the carbohydrate-binding module. Biotechnol Appl Biochem 2023; 70:290-305. [PMID: 35483889 DOI: 10.1002/bab.2352] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 04/05/2022] [Indexed: 11/11/2022]
Abstract
The processive cellulase (CelO) is an important modular enzyme of Clostridium thermocellum. To study the effect of the carbohydrate-binding module (CBM3b) on the catalytic domain of CelO (GH5), four engineered derivatives of CelO were designed by truncation and terminal fusion of CBM3b. These are CBM at the N-terminus, native form (CelO-BC, 62 kDa); catalytic domain only (CelO-C, 42 kDa); CBM at the C-terminus (CelO-CB, 54 kDa) and CBM attached at both termini (CelO-BCB, 73 kDa). All constructs were cloned into pET22b (+) and expressed in Escherichia coli BL21 (DE3) star. The expression levels of CelO-C, CelO-CB, CelO-BC, and CelO-BCB were 35%, 35%, 30%, and 20%, respectively. The enzyme activities of CelO-C, CelO-CB, CelO-BC, and CelO-BCB against 1% regenerated amorphous cellulose (RAC) were 860, 758, 985, and 1208 units per μmole of the enzyme, respectively. The enzymes were partially purified from the lysate of E. coli cells by heat treatment followed by anion exchange FPLC purification. Against RAC, CelO-C, CelO-CB, CelO-BC, and CelO-BCB showed KM values of 32, 33, 45, and 43 mg⋅mL-1 and Vmax values of 3571, 3846, 3571, and 4545 U⋅min-1 , respectively. CBM3b at the N-terminus of GH5 linked through a P/T-rich linker was found to enhance the catalytic activity and thermostability of the enzyme.
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Affiliation(s)
- Sajjad Ahmad
- School of Biological Science, University of the Punjab, Lahore, Pakistan
| | - Muhammad Sajjad
- School of Biological Science, University of the Punjab, Lahore, Pakistan
| | - Hisham N Altayb
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Syed Sarim Imam
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Sultan Alshehri
- Department of Pharmaceutical Sciences, College of Pharmacy, AlMaarefa University, Ad Diriyah, Saudi Arabia
| | - Mohammed M Ghoneim
- Department of Pharmaceutical Sciences, College of Pharmacy, AlMaarefa University, Ad Diriyah, Saudi Arabia
| | - Saher Shahid
- School of Biological Science, University of the Punjab, Lahore, Pakistan
| | - Muhammad Usman Mirza
- Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Laboratory of Medicinal Chemistry, University of Leuven, Leuven, Belgium
| | - Muhammad Shahid Nadeem
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Imran Kazmi
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
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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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7
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Sidar A, Albuquerque ED, Voshol GP, Ram AFJ, Vijgenboom E, Punt PJ. Carbohydrate Binding Modules: Diversity of Domain Architecture in Amylases and Cellulases From Filamentous Microorganisms. Front Bioeng Biotechnol 2020; 8:871. [PMID: 32850729 PMCID: PMC7410926 DOI: 10.3389/fbioe.2020.00871] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/07/2020] [Indexed: 12/11/2022] Open
Abstract
Enzymatic degradation of abundant renewable polysaccharides such as cellulose and starch is a field that has the attention of both the industrial and scientific community. Most of the polysaccharide degrading enzymes are classified into several glycoside hydrolase families. They are often organized in a modular manner which includes a catalytic domain connected to one or more carbohydrate-binding modules. The carbohydrate-binding modules (CBM) have been shown to increase the proximity of the enzyme to its substrate, especially for insoluble substrates. Therefore, these modules are considered to enhance enzymatic hydrolysis. These properties have played an important role in many biotechnological applications with the aim to improve the efficiency of polysaccharide degradation. The domain organization of glycoside hydrolases (GHs) equipped with one or more CBM does vary within organisms. This review comprehensively highlights the presence of CBM as ancillary modules and explores the diversity of GHs carrying one or more of these modules that actively act either on cellulose or starch. Special emphasis is given to the cellulase and amylase distribution within the filamentous microorganisms from the genera of Streptomyces and Aspergillus that are well known to have a great capacity for secreting a wide range of these polysaccharide degrading enzyme. The potential of the CBM and other ancillary domains for the design of improved polysaccharide decomposing enzymes is discussed.
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Affiliation(s)
- Andika Sidar
- Department of Microbial Biotechnology, Institute of Biology Leiden, Leiden, Netherlands.,Department of Food Science and Agricultural Product Technology, Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Erica D Albuquerque
- Department of Microbial Biotechnology, Institute of Biology Leiden, Leiden, Netherlands.,Sun Pharmaceutical Industries Europe BV., Hoofddorp, Netherlands
| | - Gerben P Voshol
- Department of Microbial Biotechnology, Institute of Biology Leiden, Leiden, Netherlands.,Dutch DNA Biotech B.V., Utrecht, Netherlands
| | - Arthur F J Ram
- Department of Microbial Biotechnology, Institute of Biology Leiden, Leiden, Netherlands
| | - Erik Vijgenboom
- Department of Microbial Biotechnology, Institute of Biology Leiden, Leiden, Netherlands
| | - Peter J Punt
- Department of Microbial Biotechnology, Institute of Biology Leiden, Leiden, Netherlands.,Dutch DNA Biotech B.V., Utrecht, Netherlands
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8
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Kundu S. Insights into the mechanism(s) of digestion of crystalline cellulose by plant class C GH9 endoglucanases. J Mol Model 2019; 25:240. [PMID: 31338614 PMCID: PMC7385011 DOI: 10.1007/s00894-019-4133-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 07/11/2019] [Indexed: 02/03/2023]
Abstract
Biofuels such as γ-valerolactone, bioethanol, and biodiesel are derived from potentially fermentable cellulose and vegetable oils. Plant class C GH9 endoglucanases are CBM49-encompassing hydrolases that cleave the β (1 → 4) glycosidic linkage of contiguous D-glucopyranose residues of crystalline cellulose. Here, I analyse 3D-homology models of characterised and putative class C enzymes to glean insights into the contribution of the GH9, linker, and CBM49 to the mechanism(s) of crystalline cellulose digestion. Crystalline cellulose may be accommodated in a surface groove which is imperfectly bounded by the GH9_CBM49, GH9_linker, and linker_CBM49 surfaces and thence digested in a solvent accessible subsurface cavity. The physical dimensions and distortions thereof, of the groove, are mediated in part by the bulky side chains of aromatic amino acids that comprise it and may also result in a strained geometry of the bound cellulose polymer. These data along with an almost complete absence of measurable cavities, along with poorly conserved, hydrophobic, and heterogeneous amino acid composition, increased atomic motion of the CBM49_linker junction, and docking experiements with ligands of lower degrees of polymerization suggests a modulatory rather than direct role for CBM49 in catalysis. Crystalline cellulose is the de facto substrate for CBM-containing plant and non-plant GH9 enzymes, a finding supported by exceptional sequence- and structural-homology. However, despite the implied similarity in general acid-base catalysis of crystalline cellulose, this study also highlights qualitative differences in substrate binding and glycosidic bond cleavage amongst class C members. Results presented may aid the development of novel plant-based GH9 endoglucanases that could extract and utilise potential fermentable carbohydrates from biomass. Crystalline cellulose digestion by plant class C GH9 endoglucanases - an in silico assessment of function. ![]()
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Affiliation(s)
- Siddhartha Kundu
- Department of Biochemistry, Army College of Medical Sciences, Brar Square, Delhi Cantt., New Delhi, 110010, India.
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9
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Kundu S, Sharma R. Origin, evolution, and divergence of plant class C GH9 endoglucanases. BMC Evol Biol 2018; 18:79. [PMID: 29848310 PMCID: PMC5977491 DOI: 10.1186/s12862-018-1185-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 04/18/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Glycoside hydrolases of the GH9 family encode cellulases that predominantly function as endoglucanases and have wide applications in the food, paper, pharmaceutical, and biofuel industries. The partitioning of plant GH9 endoglucanases, into classes A, B, and C, is based on the differential presence of transmembrane, signal peptide, and the carbohydrate binding module (CBM49). There is considerable debate on the distribution and the functions of these enzymes which may vary in different organisms. In light of these findings we examined the origin, emergence, and subsequent divergence of plant GH9 endoglucanases, with an emphasis on elucidating the role of CBM49 in the digestion of crystalline cellulose by class C members. RESULTS Since, the digestion of crystalline cellulose mandates the presence of a well-defined set of aromatic and polar amino acids and/or an attributable domain that can mediate this conversion, we hypothesize a vertical mode of transfer of genes that could favour the emergence of class C like GH9 endoglucanase activity in land plants from potentially ancestral non plant taxa. We demonstrated the concomitant occurrence of a GH9 domain with CBM49 and other homologous carbohydrate binding modules, in putative endoglucanase sequences from several non-plant taxa. In the absence of comparable full length CBMs, we have characterized several low strength patterns that could approximate the CBM49, thereby, extending support for digestion of crystalline cellulose to other segments of the protein. We also provide data suggestive of the ancestral role of putative class C GH9 endoglucanases in land plants, which includes detailed phylogenetics and the presence and subsequent loss of CBM49, transmembrane, and signal peptide regions in certain populations of early land plants. These findings suggest that classes A and B of modern vascular land plants may have emerged by diverging directly from CBM49 encompassing putative class C enzymes. CONCLUSION Our detailed phylogenetic and bioinformatics analysis of putative GH9 endoglucanase sequences across major taxa suggests that plant class C enzymes, despite their recent discovery, could function as the last common ancestor of classes A and B. Additionally, research into their ability to digest or inter-convert crystalline and amorphous forms of cellulose could make them lucrative candidates for engineering biofuel feedstock.
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Affiliation(s)
- Siddhartha Kundu
- Department of Biochemistry, Government of NCT of Delhi, Dr. Baba Saheb Ambedkar Medical College & Hospital, New Delhi, 110085, India. .,Crop Genetics and Informatics Group, School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Rita Sharma
- Crop Genetics and Informatics Group, School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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A bacterial GH6 cellobiohydrolase with a novel modular structure. Appl Microbiol Biotechnol 2017; 101:2943-2952. [PMID: 28120014 DOI: 10.1007/s00253-017-8129-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/19/2016] [Accepted: 12/28/2016] [Indexed: 02/01/2023]
Abstract
Cel6D from Paenibacillus barcinonensis is a modular cellobiohydrolase with a novel molecular architecture among glycosyl hydrolases of family 6. It contains an N-terminal catalytic domain (family 6 of glycosyl hydrolases (GH6)), followed by a fibronectin III-like domain repeat (Fn31,2) and a C-terminal family 3b cellulose-binding domain (CBM3b). The enzyme has been identified and purified showing catalytic activity on cellulosic substrates and cellodextrins, with a marked preference for phosphoric acid swollen cellulose (PASC). Analysis of mode of action of Cel6D shows that it releases cellobiose as the only hydrolysis product from cellulose. Kinetic parameters were determined on PASC showing a K m of 68.73 mg/ml and a V max of 1.73 U/mg. A series of truncated derivatives of Cel6D have been constructed and characterized. Deletion of CBM3b caused a notable reduction in hydrolytic activity, while deletion of the Fn3 domain abolished activity, as the isolated GH6 domain was not active on any of the substrates tested. Mutant enzymes Cel6D-D146A and Cel6D-D97A were constructed in the residues corresponding to the putative acid catalyst and to the network for the nucleophilic attack. The lack of activity of the mutant enzymes indicates the important role of these residues in catalysis. Analysis of cooperative activity of Cel6D with cellulases from the same producing P. barcinonensis strain reveals high synergistic activity with processive endoglucanase Cel9B on hydrolysis of crystalline substrates. The characterized cellobiohydrolase can be a good contribution for depolymerization of cellulosic substrates and for the deconstruction of native cellulose.
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11
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Cunha ES, Hatem CL, Barrick D. Synergistic enhancement of cellulase pairs linked by consensus ankyrin repeats: Determination of the roles of spacing, orientation, and enzyme identity. Proteins 2016; 84:1043-54. [PMID: 27071357 DOI: 10.1002/prot.25047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 03/09/2016] [Accepted: 03/25/2016] [Indexed: 12/22/2022]
Abstract
Biomass deconstruction to small simple sugars is a potential approach to biofuels production; however, the highly recalcitrant nature of biomass limits the economic viability of this approach. Thus, research on efficient biomass degradation is necessary to achieve large-scale production of biofuels. Enhancement of cellulolytic activity by increasing synergism between cellulase enzymes holds promise in achieving high-yield biofuels production. Here we have inserted cellulase pairs from extremophiles into hyperstable α-helical consensus ankyrin repeat domain scaffolds. Such chimeric constructs allowed us to optimize arrays of enzyme pairs against a variety of cellulolytic substrates. We found that endocellulolytic domains CelA (CA) and Cel12A (C12A) act synergistically in the context of ankyrin repeats, with both three and four repeat spacing. The extent of synergy differs for different substrates. Also, having C12A N-terminal to CA provides greater synergy than the reverse construct, especially against filter paper. In contrast, we do not see synergy for these enzymes in tandem with CelK (CK) catalytic domain, a larger exocellulase, demonstrating the importance of enzyme identity in synergistic enhancement. Furthermore, we found endocellulases CelD and CA with three repeat spacing to act synergistically against filter paper. Importantly, connecting CA and C12A with a disordered linker of similar contour length shows no synergistic enhancement, indicating that synergism results from connecting these domains with folded ankyrin repeats. These results show that ankyrin arrays can be used to vary spacing and orientation between enzymes, helping to design and optimize artificial cellulosomes, providing a novel architecture for synergistic enhancement of enzymatic cellulose degradation. Proteins 2016; 84:1043-1054. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Eva S Cunha
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland, 21218.,Department of Structural Biology, Max Plank Institute of Biophysics, Max-von-Laue-Str. 3, Frankfurt am Main, D-60438, Germany
| | - Christine L Hatem
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland, 21218
| | - Doug Barrick
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland, 21218
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Petkun S, Rozman Grinberg I, Lamed R, Jindou S, Burstein T, Yaniv O, Shoham Y, Shimon LJ, Bayer EA, Frolow F. Reassembly and co-crystallization of a family 9 processive endoglucanase from its component parts: structural and functional significance of the intermodular linker. PeerJ 2015; 3:e1126. [PMID: 26401442 PMCID: PMC4579020 DOI: 10.7717/peerj.1126] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 07/04/2015] [Indexed: 11/22/2022] Open
Abstract
Non-cellulosomal processive endoglucanase 9I (Cel9I) from Clostridium thermocellum is a modular protein, consisting of a family-9 glycoside hydrolase (GH9) catalytic module and two family-3 carbohydrate-binding modules (CBM3c and CBM3b), separated by linker regions. GH9 does not show cellulase activity when expressed without CBM3c and CBM3b and the presence of the CBM3c was previously shown to be essential for endoglucanase activity. Physical reassociation of independently expressed GH9 and CBM3c modules (containing linker sequences) restored 60-70% of the intact Cel9I endocellulase activity. However, the mechanism responsible for recovery of activity remained unclear. In this work we independently expressed recombinant GH9 and CBM3c with and without their interconnecting linker in Escherichia coli. We crystallized and determined the molecular structure of the GH9/linker-CBM3c heterodimer at a resolution of 1.68 Å to understand the functional and structural importance of the mutual spatial orientation of the modules and the role of the interconnecting linker during their re-association. Enzyme activity assays and isothermal titration calorimetry were performed to study and compare the effect of the linker on the re-association. The results indicated that reassembly of the modules could also occur without the linker, albeit with only very low recovery of endoglucanase activity. We propose that the linker regions in the GH9/CBM3c endoglucanases are important for spatial organization and fixation of the modules into functional enzymes.
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Affiliation(s)
- Svetlana Petkun
- Department of Molecular Microbiology and Biotechnology, The Daniella Rich Institute for Structural Biology, Tel Aviv University, Ramat Aviv, Israel
| | - Inna Rozman Grinberg
- Department of Molecular Microbiology and Biotechnology, The Daniella Rich Institute for Structural Biology, Tel Aviv University, Ramat Aviv, Israel
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, The Daniella Rich Institute for Structural Biology, Tel Aviv University, Ramat Aviv, Israel
| | - Sadanari Jindou
- Department of Life Sciences, Meijo University, Nagoya, Japan
| | - Tal Burstein
- Department of Molecular Microbiology and Biotechnology, The Daniella Rich Institute for Structural Biology, Tel Aviv University, Ramat Aviv, Israel
| | - Oren Yaniv
- Department of Molecular Microbiology and Biotechnology, The Daniella Rich Institute for Structural Biology, Tel Aviv University, Ramat Aviv, Israel
| | - Yuval Shoham
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Linda J.W. Shimon
- Department of Chemical Research Support, The Weizmann Institute of Science, Rehovot, Israel
| | - Edward A. Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Felix Frolow
- Department of Molecular Microbiology and Biotechnology, The Daniella Rich Institute for Structural Biology, Tel Aviv University, Ramat Aviv, Israel
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Ivanir-Dabora H, Nimerovsky E, Madhu PK, Goldbourt A. Site-Resolved Backbone and Side-Chain Intermediate Dynamics in a Carbohydrate-Binding Module Protein Studied by Magic-Angle Spinning NMR Spectroscopy. Chemistry 2015; 21:10778-85. [DOI: 10.1002/chem.201500856] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Indexed: 12/12/2022]
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Ivanir H, Goldbourt A. Solid state NMR chemical shift assignment and conformational analysis of a cellulose binding protein facilitated by optimized glycerol enrichment. JOURNAL OF BIOMOLECULAR NMR 2014; 59:185-197. [PMID: 24824437 DOI: 10.1007/s10858-014-9838-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 05/04/2014] [Indexed: 06/03/2023]
Abstract
Magic-angle spinning solid-state NMR has been applied to study CBM3b-Cbh9A (CBM3b), a cellulose binding module protein belonging to family 3b. It is a 146-residue protein having a unique nine-stranded β-sandwich fold, in which 35% of the structure is in a β-sheet conformation and the remainder of the protein is composed of loops and unstructured regions. Yet, the protein can be crystalized and it forms elongated needles. Close to complete chemical shift assignment of the protein was obtained by combining two- and three-dimensional experiments using a fully labeled sample and a glycerol-labeled sample. The use of an optimized protocol for glycerol-based sparse labeling reduces sample preparation costs and facilitates the assignment of the large number of aromatic signals in this protein. Conformational analysis shows good correlation between the NMR-predicted secondary structure and the reported X-ray crystal structure, in particular in the structured regions. Residues which show high B-factor values are situated mainly in unstructured regions, and are missing in our spectra indicating conformational flexibility rather than heterogeneity. Interestingly, long-range contacts, which could be clearly detected for tyrosine residues, could not be observed for aromatic phenylalanine residues pointing into the hydrophobic core, suggesting possible high ring mobility. These studies will allow us to further investigate the cellulose-bound form of CBM proteins.
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Affiliation(s)
- Hadar Ivanir
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Ramat Aviv, 69978, Tel Aviv, Israel
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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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Yaniv O, Fichman G, Borovok I, Shoham Y, Bayer EA, Lamed R, Shimon LJW, Frolow F. Fine-structural variance of family 3 carbohydrate-binding modules as extracellular biomass-sensing components of Clostridium thermocellum anti-σI factors. ACTA ACUST UNITED AC 2014; 70:522-34. [PMID: 24531486 DOI: 10.1107/s139900471302926x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/23/2013] [Indexed: 11/11/2022]
Abstract
The anaerobic, thermophilic, cellulosome-producing bacterium Clostridium thermocellum relies on a variety of carbohydrate-active enzymes in order to efficiently break down complex carbohydrates into utilizable simple sugars. The regulation mechanism of the cellulosomal genes was unknown until recently, when genomic analysis revealed a set of putative operons in C. thermocellum that encode σI factors (i.e. alternative σ factors that control specialized regulon activation) and their cognate anti-σI factor (RsgI). These putative anti-σI-factor proteins have modules that are believed to be carbohydrate sensors. Three of these modules were crystallized and their three-dimensional structures were solved. The structures show a high overall degree of sequence and structural similarity to the cellulosomal family 3 carbohydrate-binding modules (CBM3s). The structures of the three carbohydrate sensors (RsgI-CBM3s) and a reference CBM3 are compared in the context of the structural determinants for the specificity of cellulose and complex carbohydrate binding. Fine structural variations among the RsgI-CBM3s appear to result in alternative substrate preferences for each of the sensors.
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Affiliation(s)
- Oren Yaniv
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Galit Fichman
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Ilya Borovok
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Yuval Shoham
- Department of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa, Israel
| | - Edward A Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Linda J W Shimon
- Department of Chemical Research Support, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Felix Frolow
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
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