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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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Mao M, Ahrens L, Luka J, Contreras F, Kurkina T, Bienstein M, Sárria Pereira de Passos M, Schirinzi G, Mehn D, Valsesia A, Desmet C, Serra MÁ, Gilliland D, Schwaneberg U. Material-specific binding peptides empower sustainable innovations in plant health, biocatalysis, medicine and microplastic quantification. Chem Soc Rev 2024; 53:6445-6510. [PMID: 38747901 DOI: 10.1039/d2cs00991a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Material-binding peptides (MBPs) have emerged as a diverse and innovation-enabling class of peptides in applications such as plant-/human health, immobilization of catalysts, bioactive coatings, accelerated polymer degradation and analytics for micro-/nanoplastics quantification. Progress has been fuelled by recent advancements in protein engineering methodologies and advances in computational and analytical methodologies, which allow the design of, for instance, material-specific MBPs with fine-tuned binding strength for numerous demands in material science applications. A genetic or chemical conjugation of second (biological, chemical or physical property-changing) functionality to MBPs empowers the design of advanced (hybrid) materials, bioactive coatings and analytical tools. In this review, we provide a comprehensive overview comprising naturally occurring MBPs and their function in nature, binding properties of short man-made MBPs (<20 amino acids) mainly obtained from phage-display libraries, and medium-sized binding peptides (20-100 amino acids) that have been reported to bind to metals, polymers or other industrially produced materials. The goal of this review is to provide an in-depth understanding of molecular interactions between materials and material-specific binding peptides, and thereby empower the use of MBPs in material science applications. Protein engineering methodologies and selected examples to tailor MBPs toward applications in agriculture with a focus on plant health, biocatalysis, medicine and environmental monitoring serve as examples of the transformative power of MBPs for various industrial applications. An emphasis will be given to MBPs' role in detecting and quantifying microplastics in high throughput, distinguishing microplastics from other environmental particles, and thereby assisting to close an analytical gap in food safety and monitoring of environmental plastic pollution. In essence, this review aims to provide an overview among researchers from diverse disciplines in respect to material-(specific) binding of MBPs, protein engineering methodologies to tailor their properties to application demands, re-engineering for material science applications using MBPs, and thereby inspire researchers to employ MBPs in their research.
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Affiliation(s)
- Maochao Mao
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany.
| | - Leon Ahrens
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany.
| | - Julian Luka
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany.
| | - Francisca Contreras
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany.
| | - Tetiana Kurkina
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany.
| | - Marian Bienstein
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany.
| | | | | | - Dora Mehn
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Andrea Valsesia
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Cloé Desmet
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | | | - Ulrich Schwaneberg
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany.
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Shahid S, Batool S, Khaliq A, Ahmad S, Batool H, Sajjad M, Akhtar MW. Improved catalytic efficiency of chimeric xylanase 10B from Thermotoga petrophila RKU1 and its synergy with cellulases. Enzyme Microb Technol 2023; 166:110213. [PMID: 36822057 DOI: 10.1016/j.enzmictec.2023.110213] [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: 10/17/2022] [Revised: 02/11/2023] [Accepted: 02/16/2023] [Indexed: 02/21/2023]
Abstract
TpXyl10B is a glycoside hydrolase family 10 xylanase of hyperthermophile Thermotoga petrophila RKU-1. This enzyme is of considerable importance due to its thermostability. However, in its native state, this enzyme does not possess any carbohydrate-binding module (CBM) for efficient binding to plant biomass. In this study CBM6 from Clostridium thermocellum was attached to the N- and C-termini of TpXyl10B, thereby producing the variants TpXyl10B-B6C and TpXyl10B-CB6, respectively. TpXyl10B-B6C showed 5-7 folds increased activity on Beechwood xylan and the different types of plant biomass as compared to that from the catalytic domain only. However, the activity of TpXyl10B-CB6 decreased 0.6-0.8 folds on Beechwood xylan and plant biomass compared to the catalytic domain. We explained these results through molecular modeling, which showed that binding residues of CBM6's cleft B, which were previously reported to show no contribution towards binding due to steric hindrance from a loop region, were exposed in a favorable position in TpXyl10B-B6C such that they efficiently bound the substrate. In contrast, these binding residues of CBM6 in TpXyl10B-CB6 were exposed opposite to the catalytic residues; thus, binding to the substrate resulted in decreased exposure of catalytic residues to the substrate. CD spectroscopy and thermostability assays showed that TpXyl10B-B6C was highly thermostable, having a melting point > 90 °C, which is relatively higher than that of the other variant, TpXyl10B-CB6. In addition, this xylanase variant showed synergism with cellulases for the hydrolysis of plant biomass. Therefore, TpXyl10B-B6C, an engineered xylanase in this study, can be a valuable candidate for industrial applications.
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Affiliation(s)
- Saher Shahid
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, Pakistan; Department of Biochemistry and Biophysics, Stockholm University, Sweden.
| | - Sana Batool
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, Pakistan
| | - Aasia Khaliq
- Department of Life Sciences, Lahore University of Management Sciences, Lahore, Pakistan.
| | - Sajjad Ahmad
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, Pakistan; DNA and Serology Lab, Punjab Forensic Science Agency, Lahore, Pakistan
| | - Hina Batool
- Department of Life Sciences, School of Science, University of Management and Technology, Johar Town, Lahore, Pakistan.
| | - Muhammad Sajjad
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, Pakistan.
| | - Muhammad Waheed Akhtar
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, Pakistan.
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Yadav V, Ahmed J, Thakur A, Vishwakarma P, Singh S, Kaur P, Goyal A. Structural insights of a putative β-1,4-xylosidase (PsGH43F) of glycoside hydrolase family 43 from Pseudopedobacter saltans. Int J Biol Macromol 2022; 221:751-762. [PMID: 36099997 DOI: 10.1016/j.ijbiomac.2022.09.072] [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: 06/28/2022] [Revised: 08/29/2022] [Accepted: 09/08/2022] [Indexed: 11/26/2022]
Abstract
Structural and conformational insights of a putative β-1,4-xylosidase (PsGH43F) of glycoside hydrolase family 43 from Pseudopedobacter saltans were investigated by computational and Circular Dichroism (CD) analyses. PsGH43F was cloned and expressed in E. coli BL21 (DE3) cells and the purified enzyme gave the size ~50 kDa on SDS-PAGE analysis. Multiple Sequence Alignment of PsGH43F sequence followed by superposition of modeled structure with homologous structures displayed the presence of three conserved catalytic amino acid residues, Asp33, Asp149 and Glu212. The secondary structure analysis by CD showed 2.72 % α-helix and 36.06 % β-strands. The homology modeled structure of PsGH43F displayed a 5-bladed β-propeller fold for catalytic module at N-terminal and a β-sandwich structure for CBM6 at the C-terminal. Ramachandran plot displayed 99.5 % of residues in the allowed regions. MD simulation of PsGH43F revealed the compactness and stability of the structure. Molecular docking studies of PsGH43F with xylo-oligosaccharides revealed its maximum binding affinity for xylobiose. MD simulation of PsGH43F-xylobiose complex confirmed the increased structural and conformational stability in presence of substrate. The Hydrodynamic diameter analysis of PsGH43F by DLS was in the range, 0.25-0.28 μm.
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Affiliation(s)
- Vishwanath Yadav
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Jebin Ahmed
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Abhijeet Thakur
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India; Department of Newborn Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Poorvi Vishwakarma
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Shubha Singh
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Punit Kaur
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Arun Goyal
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India.
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5
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Salmeán AA, Willats WGT, Ribeiro S, Andersen TJ, Ellegaard M. Over 100-Year Preservation and Temporal Fluctuations of Cell Wall Polysaccharides in Marine Sediments. FRONTIERS IN PLANT SCIENCE 2022; 13:785902. [PMID: 35519816 PMCID: PMC9062592 DOI: 10.3389/fpls.2022.785902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 02/28/2022] [Indexed: 05/16/2023]
Abstract
Polysaccharides constitute an important carbon pool in marine systems, but much is still unknown about the fate and degradation of these compounds. They are derived partly from production in situ, and in coastal areas, they are partly terrestrially derived, originating from freshwater runoff from land. The aim of this study was to test the applicability of high-throughput polysaccharide profiling for plant and algal cell-wall compounds in dated sediment cores from a coastal marine environment, to examine the preservation of cell-wall polysaccharides and explore their potential as proxies for temporal environmental changes. Preserved compounds and remains of organisms are routinely used as paleoenvironmental proxies as the amount and composition of different compounds that can provide insight into past environmental conditions, and novel means for reporting environmental changes are highly sought.
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Affiliation(s)
- Armando A. Salmeán
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- Department of Technology, University College Copenhagen, Copenhagen, Denmark
| | - William George Tycho Willats
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Sofia Ribeiro
- Geological Survey of Denmark and Greenland, Copenhagen, Denmark
| | - Thorbjørn Joest Andersen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Marianne Ellegaard
- Department of Technology, University College Copenhagen, Copenhagen, Denmark
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6
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Kouadio JL, Zheng M, Aikins M, Duda D, Duff S, Chen D, Zhang J, Milligan J, Taylor C, Mamanella P, Rydel T, Kessenich C, Panosian T, Yin Y, Moar W, Giddings K, Park Y, Jerga A, Haas J. Structural and functional insights into the first Bacillus thuringiensis vegetative insecticidal protein of the Vpb4 fold, active against western corn rootworm. PLoS One 2021; 16:e0260532. [PMID: 34928980 PMCID: PMC8687597 DOI: 10.1371/journal.pone.0260532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 11/11/2021] [Indexed: 01/09/2023] Open
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major maize pest in the United States causing significant economic loss. The emergence of field-evolved resistant WCR to Bacillus thuringiensis (Bt) traits has prompted the need to discover and deploy new insecticidal proteins in transgenic maize. In the current study we determined the crystal structure and mode of action (MOA) of the Vpb4Da2 protein (formerly known as Vip4Da2) from Bt, the first identified insecticidal Vpb4 protein with commercial level control against WCR. The Vpb4Da2 structure exhibits a six-domain architecture mainly comprised of antiparallel β-sheets organized into β-sandwich layers. The amino-terminal domains 1-3 of the protein share structural homology with the protective antigen (PA) PA14 domain and encompass a long β-pore forming loop as in the clostridial binary-toxB module. Domains 5 and 6 at the carboxyl-terminal half of Vpb4Da2 are unique as this extension is not observed in PA or any other structurally-related protein other than Vpb4 homologs. These unique Vpb4 domains adopt the topologies of carbohydrate-binding modules known to participate in receptor-recognition. Functional assessment of Vpb4Da2 suggests that domains 4-6 comprise the WCR receptor binding region and are key in conferring the observed insecticidal activity against WCR. The current structural analysis was complemented by in vitro and in vivo characterizations, including immuno-histochemistry, demonstrating that Vpb4Da2 follows a MOA that is consistent with well-characterized 3-domain Bt insecticidal proteins despite significant structural differences.
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Affiliation(s)
| | - Meiying Zheng
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Michael Aikins
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - David Duda
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Stephen Duff
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Danqi Chen
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jun Zhang
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jason Milligan
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Christina Taylor
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | | | - Timothy Rydel
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Colton Kessenich
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Timothy Panosian
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yong Yin
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - William Moar
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Kara Giddings
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yoonseong Park
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - Agoston Jerga
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jeffrey Haas
- Bayer Crop Science, Chesterfield, Missouri, United States of America
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Significance of a family-6 carbohydrate-binding module in a modular feruloyl esterase for removing ferulic acid from insoluble wheat arabinoxylan. Enzyme Microb Technol 2020; 138:109546. [DOI: 10.1016/j.enzmictec.2020.109546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/23/2020] [Accepted: 03/03/2020] [Indexed: 11/21/2022]
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8
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Sharma K, Fontes CMGA, Najmudin S, Goyal A. Small angle X-ray scattering based structure, modeling and molecular dynamics analyses of family 43 glycoside hydrolase α-L-arabinofuranosidase from Clostridium thermocellum. J Biomol Struct Dyn 2019; 39:209-218. [PMID: 31856699 DOI: 10.1080/07391102.2019.1707119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Enzymes that participate in the hydrolysis of complex carbohydrates display a modular architecture, although the significance of enzyme modularity to flexibility and catalytic efficacy is not fully understood. α-L-arabinofuranosidase from Clostridium thermocellum (CtAraf43) catalyzes the release of α-1,2-, α-1,3-, or α-1,5- linked L-arabinose from arabinose decorated polysaccharides. CtAraf43 comprises an N-terminal catalytic domain (CtAbf43A) connected with two family 6 carbohydrate-binding modules (CBMs), termed as CtCBM6A and CtCBM6B, through flexible linker peptides. Here, we modeled the structure of CtAraf43 revealing that the module, CtAbf43A displays a 5-fold β-propeller fold and the CBMs the typical jellyroll type β-sandwich folds. Ramachandran plot showed 98.5% residues in the favored region and 1.5% residues in the disallowed region. Molecular dynamics simulation analysis of CtAraf43 revealed significant flexibility that is more expressive in the C-terminal CtCBM6B module in terms of structure and orientation. Small angle X-ray scattering analysis of CtAraf43 revealed its elongated structure. CtAraf43 at 1.2 mg/mL demonstrated the monomeric nature and a multi-modular shaped molecular envelope in solution with a Dmax of 12 nm. However, at 4.7 mg/mL, CtAraf43 displayed a dimeric structure and elongated molecular envelope. Kratky plot analysis revealed the folded state of CtAraf43 with limited flexibility at both concentrations. The data revealed higher flexibility at the C-terminal of CtAraf43 suggesting a coordinated action of the N-terminal catalytic module CtAbf43A and the internal CtCBM6A.AbbreviationCBMsCarbohydrate Binding ModulesCtAraf43α-L-arabinofuranosidaseGHsGlycoside HydrolasesMDMolecular DynamicsRMSDRoot Mean Square DeviationRMSFRoot Mean Square FluctuationSAXSSmall angle X-ray scatteringCommunicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kedar Sharma
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Carlos M G A Fontes
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Shabir Najmudin
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Arun Goyal
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
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Leth ML, Ejby M, Madland E, Kitaoku Y, Slotboom DJ, Guskov A, Aachmann FL, Abou Hachem M. Molecular insight into a new low‐affinity xylan binding module from the xylanolytic gut symbiont
Roseburia intestinalis. FEBS J 2019; 287:2105-2117. [DOI: 10.1111/febs.15117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/09/2019] [Accepted: 10/29/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Maria Louise Leth
- Department of Biotechnology and Biomedicine Technical University of Denmark Lyngby Denmark
| | - Morten Ejby
- Department of Biotechnology and Biomedicine Technical University of Denmark Lyngby Denmark
| | - Eva Madland
- NOBIPOL Department of Biotechnology and Food Science NTNU Norwegian University of Science and Technology Trondheim Norway
| | - Yoshihito Kitaoku
- NOBIPOL Department of Biotechnology and Food Science NTNU Norwegian University of Science and Technology Trondheim Norway
| | - Dirk J. Slotboom
- Membrane Enzymology Institute for Biomolecular Sciences & Biotechnology University of Groningen Groningen The Netherlands
| | - Albert Guskov
- Membrane Enzymology Institute for Biomolecular Sciences & Biotechnology University of Groningen Groningen The Netherlands
| | - Finn Lillelund Aachmann
- NOBIPOL Department of Biotechnology and Food Science NTNU Norwegian University of Science and Technology Trondheim Norway
| | - Maher Abou Hachem
- Department of Biotechnology and Biomedicine Technical University of Denmark Lyngby Denmark
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10
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Sharma K, Fontes CMGA, Najmudin S, Goyal A. Molecular organization and protein stability of the Clostridium thermocellum glucuronoxylan endo-β-1,4-xylanase of family 30 glycoside hydrolase in solution. J Struct Biol 2019; 206:335-344. [PMID: 30959107 DOI: 10.1016/j.jsb.2019.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/02/2019] [Accepted: 04/04/2019] [Indexed: 11/19/2022]
Abstract
Glucuronoxylan-β-1,4-xylanohydrolase from Clostridium thermocellum (CtXynGH30) hydrolyzes β-1,4-xylosidic linkages in 4-O-Methyl-D-glucuronoxylan. CtXynGH30 comprises an N-terminal catalytic domain, CtXyn30A, joined by a typical linker sequence to a family 6 carbohydrate-binding module, termed CtCBM6. ITC, mass spectrometric and enzyme activity analyses of CtXyn30A:CtCBM6 (1:1 M ratio), CtXyn30A and CtXynGH30 showed that the linker peptide plays a key role in connecting and orienting CtXyn30A and CtCBM6 modules resulting in the enhanced activity of CtXynGH30. To visualize the disposition of the two protein domains of CtXynGH30, SAXS analysis revealed that CtXynGH30 is monomeric and has a boot-shaped molecular envelope in solution with a Dmax of 18 nm and Rg of 3.6 nm. Kratky plot displayed the protein in a fully folded and flexible state. The ab initio derived dummy atom model of CtXynGH30 superposed well with the modelled structure.
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Affiliation(s)
- Kedar Sharma
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Carlos M G A Fontes
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Shabir Najmudin
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Arun Goyal
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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11
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NMR Analysis on Molecular Interaction of Lignin with Amino Acid Residues of Carbohydrate-Binding Module from Trichoderma reesei Cel7A. Sci Rep 2019; 9:1977. [PMID: 30760856 PMCID: PMC6374431 DOI: 10.1038/s41598-018-38410-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
Lignocellulosic biomass is anticipated to serve as a platform for green chemicals and fuels. Nonproductive binding of lignin to cellulolytic enzymes should be avoided for conversion of lignocellulose through enzymatic saccharification. Although carbohydrate-binding modules (CBMs) of cellulolytic enzymes strongly bind to lignin, the adsorption mechanism at molecular level is still unclear. Here, we report NMR-based analyses of binding sites on CBM1 of cellobiohydrolase I (Cel7A) from a hyper-cellulase-producing fungus, Trichoderma reesei, with cellohexaose and lignins from Japanese cedar (C-MWL) and Eucalyptus globulus (E-MWL). A method was established to obtain properly folded TrCBM1. Only TrCBM1 that was expressed in freshly transformed E. coli had intact conformation. Chemical shift perturbation analyses revealed that TrCBM1 adsorbed cellohexaose in highly specific manner via two subsites, flat plane surface and cleft, which were located on the opposite side of the protein surface. Importantly, MWLs were adsorbed at multiple binding sites, including the subsites, having higher affinity than cellohexaose. G6 and Q7 were involved in lignin binding on the flat plane surface of TrCBM1, while cellohexaose preferentially interacted with N29 and Q34. TrCBM1 used much larger surface area to bind with C-MWL than E-MWL, indicating the mechanisms of adsorption toward hardwood and softwood lignins are different.
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12
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Sakka M, Kunitake E, Kimura T, Sakka K. Function of a laminin_G_3 module as a carbohydrate-binding module in an arabinofuranosidase from Ruminiclostridium josui. FEBS Lett 2018; 593:42-51. [PMID: 30403289 DOI: 10.1002/1873-3468.13283] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/23/2018] [Accepted: 10/30/2018] [Indexed: 11/09/2022]
Abstract
Laminin_G_3 modules can exist together with family-43 catalytic modules of glycoside hydrolase (GH43), but their functions are unknown. Here, a laminin_G_3 module and a GH43 module derived from a Ruminiclostridium josui modular arabinofuranosidase Abf43A-Abf43B-Abf43C were produced individually as RjLG3 and RjGH43_22, respectively, or combined as RjGH43-1 to gain insights into their activities. Isothermal calorimetry analysis showed that RjLG3 has high affinity toward 32 -α-l-arabinofuranosyl-(1,5)-α-l-arabinotriose but not for α-1,5-linked arabinooligosaccharides, which suggests that RjLG3 interacts specifically with a branched arabinofuranosyl residue of an arabinooligosaccharide but not an arabinofuranosyl residue at the end of α-1,5-linked arabinooligosaccharides. RjGH43-1 (with CBM) shows higher activity toward sugar beet arabinan than RjGH43_22 (without CBM), which suggests that the LG3 module in RjGH43-1 plays an important role in substrate hydrolysis as a carbohydrate-binding module.
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Affiliation(s)
- Makiko Sakka
- Graduate School of Bioresources, Mie University, Tsu, Japan
| | - Emi Kunitake
- Graduate School of Bioresources, Mie University, Tsu, Japan
| | - Tetsuya Kimura
- Graduate School of Bioresources, Mie University, Tsu, Japan
| | - Kazuo Sakka
- Graduate School of Bioresources, Mie University, Tsu, Japan
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13
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Tajwar R, Shahid S, Zafar R, Akhtar MW. Impact of orientation of carbohydrate binding modules family 22 and 6 on the catalytic activity of Thermotoga maritima xylanase XynB. Enzyme Microb Technol 2017; 106:75-82. [DOI: 10.1016/j.enzmictec.2017.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 06/09/2017] [Accepted: 07/07/2017] [Indexed: 10/19/2022]
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14
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Kim SK, Chung D, Himmel ME, Bomble YJ, Westpheling J. In vivo synergistic activity of a CAZyme cassette from Acidothermus cellulolyticus significantly improves the cellulolytic activity of the C. bescii exoproteome. Biotechnol Bioeng 2017. [PMID: 28650071 DOI: 10.1002/bit.26366] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The use of microbial cells to convert plant biomass directly to fuels and chemicals is referred to as consolidated bioprocessing (CBP). Members of the bacterial genus, Caldicellulosiruptor (Gram-positive, anaerobic hyperthermophiles) are capable of deconstructing plant biomass without enzymatic or chemical pretreatment. This is accomplished by the production and secretion of free, multi-domain enzymes that outperform commercial enzyme cocktails on some substrates. Here, we show that the exoproteome of Caldicellulosiruptor bescii may be enhanced by the heterologous expression of enzymes from Acidothermus cellulolyticus that act synergistically to improve sugar release from complex substrates; as well as improve cell growth. In this work, co-expression of the A. cellulolyticus Acel_0615 β-glucanase (GH6 and GH12) and E1 endoglucanase (GH5) enzymes resulted in an increase in the activity of the exoproteome on Avicel; as well as an increase in growth of C. bescii on Avicel compared to the parental strain or the strain expressing the β-glucanase alone. Our ability to engineer the composition and effectiveness of the exoproteome of these bacteria provides insight into the natural mechanism of plant cell wall deconstruction, as well as future directions for improving CBP. Biotechnol. Bioeng. 2017;114: 2474-2480. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Sun-Ki Kim
- Department of Genetics, University of Georgia, Athens, Georgia, 30602.,The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831
| | - Daehwan Chung
- The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831.,Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado
| | - Michael E Himmel
- The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831.,Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado
| | - Yannick J Bomble
- The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831.,Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado
| | - Janet Westpheling
- Department of Genetics, University of Georgia, Athens, Georgia, 30602.,The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831
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15
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Walker JA, Pattathil S, Bergeman LF, Beebe ET, Deng K, Mirzai M, Northen TR, Hahn MG, Fox BG. Determination of glycoside hydrolase specificities during hydrolysis of plant cell walls using glycome profiling. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:31. [PMID: 28184246 PMCID: PMC5288845 DOI: 10.1186/s13068-017-0703-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/06/2017] [Indexed: 05/29/2023]
Abstract
BACKGROUND Glycoside hydrolases (GHs) are enzymes that hydrolyze polysaccharides into simple sugars. To better understand the specificity of enzyme hydrolysis within the complex matrix of polysaccharides found in the plant cell wall, we studied the reactions of individual enzymes using glycome profiling, where a comprehensive collection of cell wall glycan-directed monoclonal antibodies are used to detect polysaccharide epitopes remaining in the walls after enzyme treatment and quantitative nanostructure initiator mass spectrometry (oxime-NIMS) to determine soluble sugar products of their reactions. RESULTS Single, purified enzymes from the GH5_4, GH10, and GH11 families of glycoside hydrolases hydrolyzed hemicelluloses as evidenced by the loss of specific epitopes from the glycome profiles in enzyme-treated plant biomass. The glycome profiling data were further substantiated by oxime-NIMS, which identified hexose products from hydrolysis of cellulose, and pentose-only and mixed hexose-pentose products from the hydrolysis of hemicelluloses. The GH10 enzyme proved to be reactive with the broadest diversity of xylose-backbone polysaccharide epitopes, but was incapable of reacting with glucose-backbone polysaccharides. In contrast, the GH5 and GH11 enzymes studied here showed the ability to react with both glucose- and xylose-backbone polysaccharides. CONCLUSIONS The identification of enzyme specificity for a wide diversity of polysaccharide structures provided by glycome profiling, and the correlated identification of soluble oligosaccharide hydrolysis products provided by oxime-NIMS, offers a unique combination to understand the hydrolytic capabilities and constraints of individual enzymes as they interact with plant biomass.
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Affiliation(s)
- Johnnie A. Walker
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Sivakumar Pattathil
- US Department of Energy Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Lai F. Bergeman
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Emily T. Beebe
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Kai Deng
- US Department of Energy Joint Bioenergy Institute, Emeryville, CA 94608 USA
- Sandia National Laboratories, Livermore, CA 94551 USA
| | - Maryam Mirzai
- US Department of Energy Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Trent R. Northen
- US Department of Energy Joint Bioenergy Institute, Emeryville, CA 94608 USA
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Michael G. Hahn
- US Department of Energy Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Brian G. Fox
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
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16
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Sermsathanaswadi J, Baramee S, Tachaapaikoon C, Pason P, Ratanakhanokchai K, Kosugi A. The family 22 carbohydrate-binding module of bifunctional xylanase/β-glucanase Xyn10E from Paenibacillus curdlanolyticus B-6 has an important role in lignocellulose degradation. Enzyme Microb Technol 2017; 96:75-84. [DOI: 10.1016/j.enzmictec.2016.09.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/05/2016] [Accepted: 09/24/2016] [Indexed: 10/20/2022]
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17
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Furusawa G, Lau NS, Suganthi A, Amirul AAA. Agarolytic bacterium Persicobacter sp. CCB-QB2 exhibited a diauxic growth involving galactose utilization pathway. Microbiologyopen 2016; 6. [PMID: 27987272 PMCID: PMC5300873 DOI: 10.1002/mbo3.405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 08/26/2016] [Accepted: 08/29/2016] [Indexed: 11/18/2022] Open
Abstract
The agarolytic bacterium Persicobacter sp. CCB‐QB2 was isolated from seaweed (genus Ulva) collected from a coastal area of Malaysia. Here, we report a high‐quality draft genome sequence for QB2. The Rapid Annotation using Subsystem Technology (RAST) annotation server identified four β‐agarases (PdAgaA, PdAgaB, PdAgaC, and PdAgaD) as well as galK, galE, and phosphoglucomutase, which are related to the Leloir pathway. Interestingly, QB2 exhibited a diauxic growth in the presence of two kinds of nutrients, such as tryptone and agar. In cells grown with agar, the profiles of agarase activity and growth rate were very similar. galK, galE, and phosphoglucomutase genes were highly expressed in the second growth phase of diauxic growth, indicating that QB2 cells use galactose hydrolyzed from agar by its agarases and exhibit nutrient prioritization. This is the first report describing diauxic growth for agarolytic bacteria. QB2 is a potential novel model organism for studying diauxic growth in environmental bacteria.
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Affiliation(s)
- Go Furusawa
- Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas, Malaysia
| | - Nyok-Sean Lau
- Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas, Malaysia
| | - Appalasamy Suganthi
- Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas, Malaysia.,Faculty of Earth Science, Universiti Malaysia Kelantan, Jeli, Malaysia
| | - Abdullah Al-Ashraf Amirul
- Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas, Malaysia.,School of Biological Sciences, Universiti Sains Malaysia, Minden, Malaysia
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18
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Liu S, Ding S. Replacement of carbohydrate binding modules improves acetyl xylan esterase activity and its synergistic hydrolysis of different substrates with xylanase. BMC Biotechnol 2016; 16:73. [PMID: 27770795 PMCID: PMC5075172 DOI: 10.1186/s12896-016-0305-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/13/2016] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Acetylation of the xylan backbone was a major obstacle to enzymatic decomposition. Removal of acetyl groups by acetyl xylan esterases (AXEs) is essential for completely enzymatic hydrolysis of xylan. Appended carbohydrate binding modules (CBMs) can promote the enzymatic deconstruction of plant cell walls by targeting and proximity effects. Fungal acetyl xylan esterases are strictly appended to cellulose-specific CBM1. It is still unclear whether xylan-specific CBMs have a greater advantage than CBM1 in potentiating the activity of fungal deacetylating enzymes and its synergistic hydrolysis of different substrates with xylanase. RESULTS Three recombinant AXE1s fused with different xylan-specific CBMs, together with wild-type AXE1 with CBM1 and CBM1-deleted mutant AXE1dC, were constructed in this study. The optimal temperature and pH of recombinant AXE1s was 50 °C and 8.0 (except AXE1dC-CBM6), respectively. Cellulose-specific CBM1 in AXE1 obviously contributed to its catalytic action against substrates compared with AXE1dC. However, replacement of CBM1 with xylan-specific CBM4-2 significantly enhanced AXE1 thermostability and catalytic activity against soluble substrate 4-methylumbelliferyl acetate. Whereas replacements with xylan-specific CBM6 and CBM22-2 were more effective in enzymatic release of acetic acid from destarched wheat bran, NaClO2-treated wheat straw, and water-insoluble wheat arabinoxylan compared to AXE1. Moreover, replacement with CBM6 and CBM22-2 also resulted in higher degree releases of reducing sugar and acetic acid from different substrates when simultaneous hydrolysis with xylanase. A good linear relationship exists between the acetic acid and reducing sugar release. CONCLUSIONS Our findings suggested that the replacement with CBM6 and CBM22-2 not only significantly improved the catalysis efficiency of AXE1, but also increased its synergistic hydrolysis of different substrates with xylanase, indicating the significance of targeting effect in AXE1 catalysis mediated by xylan-specific CBMs.
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Affiliation(s)
- Shiping Liu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Shaojun Ding
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China.
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19
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Jam M, Ficko-Blean E, Labourel A, Larocque R, Czjzek M, Michel G. Unraveling the multivalent binding of a marine family 6 carbohydrate-binding module with its native laminarin ligand. FEBS J 2016; 283:1863-79. [DOI: 10.1111/febs.13707] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 02/12/2016] [Accepted: 03/07/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Murielle Jam
- Sorbonne Université; UPMC Univ Paris 06, CNRS, UMR 8227; Integrative Biology of Marine Models; Station Biologique de Roscoff; Roscoff Cedex Bretagne France
| | - Elizabeth Ficko-Blean
- Sorbonne Université; UPMC Univ Paris 06, CNRS, UMR 8227; Integrative Biology of Marine Models; Station Biologique de Roscoff; Roscoff Cedex Bretagne France
| | - Aurore Labourel
- Sorbonne Université; UPMC Univ Paris 06, CNRS, UMR 8227; Integrative Biology of Marine Models; Station Biologique de Roscoff; Roscoff Cedex Bretagne France
| | - Robert Larocque
- Sorbonne Université; UPMC Univ Paris 06, CNRS, UMR 8227; Integrative Biology of Marine Models; Station Biologique de Roscoff; Roscoff Cedex Bretagne France
| | - Mirjam Czjzek
- Sorbonne Université; UPMC Univ Paris 06, CNRS, UMR 8227; Integrative Biology of Marine Models; Station Biologique de Roscoff; Roscoff Cedex Bretagne France
| | - Gurvan Michel
- Sorbonne Université; UPMC Univ Paris 06, CNRS, UMR 8227; Integrative Biology of Marine Models; Station Biologique de Roscoff; Roscoff Cedex Bretagne France
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20
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Goldstone DC, Metcalf P, Baker EN. Structure of the ectodomain of the electron transporter Rv2874 fromMycobacterium tuberculosisreveals a thioredoxin-like domain combined with a carbohydrate-binding module. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:40-8. [DOI: 10.1107/s2059798315021488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 11/12/2015] [Indexed: 11/10/2022]
Abstract
The members of the CcdA family are integral membrane proteins that use a disulfide cascade to transport electrons from the thioredoxin–thioredoxin reductase system in the interior of the cell into the extracytoplasmic space. The core transmembrane portion of this family is often elaborated with additional hydrophilic domains that act as adapters to deliver reducing potential to targets outside the cellular membrane. To investigate the function of family members inMycobacterium tuberculosis, the structure of the C-terminal ectodomain from Rv2874, one of three CcdA-family members present in the genome, was determined. The crystal structure, which was refined at 1.9 Å resolution withR= 0.195 andRfree= 0.219, reveals the predicted thioredoxin-like domain with its conserved Cys-X-X-Cys active-site motif. Unexpectedly, this domain is combined with a second domain with a carbohydrate-binding module (CBM) fold, this being the first reported example of a CBM in association with a thioredoxin-like domain fold. A cavity in the CBM adjacent to the thioredoxin active site suggests a likely carbohydrate-binding site, representing a broadening of the substrate range for CcdA-family members and an expansion of the thioredoxin-domain functionality to carbohydrate modification.
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21
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Pattathil S, Avci U, Zhang T, Cardenas CL, Hahn MG. Immunological Approaches to Biomass Characterization and Utilization. Front Bioeng Biotechnol 2015; 3:173. [PMID: 26579515 PMCID: PMC4623462 DOI: 10.3389/fbioe.2015.00173] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 10/12/2015] [Indexed: 11/13/2022] Open
Abstract
Plant biomass is the major renewable feedstock resource for sustainable generation of alternative transportation fuels to replace fossil carbon-derived fuels. Lignocellulosic cell walls are the principal component of plant biomass. Hence, a detailed understanding of plant cell wall structure and biosynthesis is an important aspect of bioenergy research. Cell walls are dynamic in their composition and structure, varying considerably among different organs, cells, and developmental stages of plants. Hence, tools are needed that are highly efficient and broadly applicable at various levels of plant biomass-based bioenergy research. The use of plant cell wall glycan-directed probes has seen increasing use over the past decade as an excellent approach for the detailed characterization of cell walls. Large collections of such probes directed against most major cell wall glycans are currently available worldwide. The largest and most diverse set of such probes consists of cell wall glycan-directed monoclonal antibodies (McAbs). These McAbs can be used as immunological probes to comprehensively monitor the overall presence, extractability, and distribution patterns among cell types of most major cell wall glycan epitopes using two mutually complementary immunological approaches, glycome profiling (an in vitro platform) and immunolocalization (an in situ platform). Significant progress has been made recently in the overall understanding of plant biomass structure, composition, and modifications with the application of these immunological approaches. This review focuses on such advances made in plant biomass analyses across diverse areas of bioenergy research.
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Affiliation(s)
- Sivakumar Pattathil
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Oak Ridge National Laboratory, BioEnergy Science Center (BESC), Oak Ridge, TN, USA
| | - Utku Avci
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Oak Ridge National Laboratory, BioEnergy Science Center (BESC), Oak Ridge, TN, USA
| | - Tiantian Zhang
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Claudia L. Cardenas
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Michael G. Hahn
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Oak Ridge National Laboratory, BioEnergy Science Center (BESC), Oak Ridge, TN, USA
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22
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Molecular engineering of cycloisomaltooligosaccharide glucanotransferase from Bacillus circulans T-3040: structural determinants for the reaction product size and reactivity. Biochem J 2015; 467:259-70. [PMID: 25649478 DOI: 10.1042/bj20140860] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cycloisomaltooligosaccharide glucanotransferase (CITase) is a member of glycoside hydrolase family 66 and it produces cycloisomaltooligosaccharides (CIs). Small CIs (CI-7-9) and large CIs (CI-≥10) are designated as oligosaccharide-type CIs (oligo-CIs) and megalosaccharide-type CIs (megalo-CIs) respectively. CITase from Bacillus circulans T-3040 (BcCITase) produces mainly CI-8 with little megalo-CIs. It has two family 35 carbohydrate-binding modules (BcCBM35-1 and BcCBM35-2). BcCBM35-1 is inserted in a catalytic domain of BcCITase and BcCBM35-2 is located at the C-terminal region. Our previous studies suggested that BcCBM35-1 has two substrate-binding sites (B-1 and B-2) [Suzuki et al. (2014) J. Biol. Chem. 289, 12040-12051]. We implemented site-directed mutagenesis of BcCITase to explore the preference for product size on the basis of the 3D structure of BcCITase. Mutational studies provided evidence that B-1 and B-2 contribute to recruiting substrate and maintaining product size respectively. A mutant (mutant-R) with four mutations (F268V, D469Y, A513V and Y515S) produced three times as much megalo-CIs (CI-10-12) and 1.5 times as much total CIs (CI-7-12) as compared with the wild-type (WT) BcCITase. The 3D structure of the substrate-enzyme complex of mutant-R suggested that the modified product size specificity was attributable to the construction of novel substrate-binding sites in the B-2 site of BcCBM35-1 and reactivity was improved by mutation on subsite -3 on the catalytic domain.
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23
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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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24
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Walker JA, Takasuka TE, Deng K, Bianchetti CM, Udell HS, Prom BM, Kim H, Adams PD, Northen TR, Fox BG. Multifunctional cellulase catalysis targeted by fusion to different carbohydrate-binding modules. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:220. [PMID: 26697109 PMCID: PMC4687162 DOI: 10.1186/s13068-015-0402-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 11/30/2015] [Indexed: 05/11/2023]
Abstract
BACKGROUND Carbohydrate binding modules (CBMs) bind polysaccharides and help target glycoside hydrolases catalytic domains to their appropriate carbohydrate substrates. To better understand how CBMs can improve cellulolytic enzyme reactivity, representatives from each of the 18 families of CBM found in Ruminoclostridium thermocellum were fused to the multifunctional GH5 catalytic domain of CelE (Cthe_0797, CelEcc), which can hydrolyze numerous types of polysaccharides including cellulose, mannan, and xylan. Since CelE is a cellulosomal enzyme, none of these fusions to a CBM previously existed. RESULTS CelEcc_CBM fusions were assayed for their ability to hydrolyze cellulose, lichenan, xylan, and mannan. Several CelEcc_CBM fusions showed enhanced hydrolytic activity with different substrates relative to the fusion to CBM3a from the cellulosome scaffoldin, which has high affinity for binding to crystalline cellulose. Additional binding studies and quantitative catalysis studies using nanostructure-initiator mass spectrometry (NIMS) were carried out with the CBM3a, CBM6, CBM30, and CBM44 fusion enzymes. In general, and consistent with observations of others, enhanced enzyme reactivity was correlated with moderate binding affinity of the CBM. Numerical analysis of reaction time courses showed that CelEcc_CBM44, a combination of a multifunctional enzyme domain with a CBM having broad binding specificity, gave the fastest rates for hydrolysis of both the hexose and pentose fractions of ionic-liquid pretreated switchgrass. CONCLUSION We have shown that fusions of different CBMs to a single multifunctional GH5 catalytic domain can increase its rate of reaction with different pure polysaccharides and with pretreated biomass. This fusion approach, incorporating domains with broad specificity for binding and catalysis, provides a new avenue to improve reactivity of simple combinations of enzymes within the complexity of plant biomass.
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Affiliation(s)
- Johnnie A. Walker
- />US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- />Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Taichi E. Takasuka
- />US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- />Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
- />Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Kai Deng
- />US Department of Energy Joint BioEnergy Institute, Emeryville, CA 94608 USA
- />Sandia National Laboratories, Livermore, CA 94551 USA
| | - Christopher M. Bianchetti
- />US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- />Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
- />Department of Chemistry, University of Wisconsin-Oshkosh, Oshkosh, WI 54901 USA
| | - Hannah S. Udell
- />US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Ben M. Prom
- />US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Hyunkee Kim
- />US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Paul D. Adams
- />US Department of Energy Joint BioEnergy Institute, Emeryville, CA 94608 USA
- />Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- />Department of Bioengineering, University of California, Berkeley, CA 94720 USA
| | - Trent R. Northen
- />US Department of Energy Joint BioEnergy Institute, Emeryville, CA 94608 USA
- />Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Brian G. Fox
- />US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706 USA
- />Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
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Ahmed S, Luís AS, Brás JLA, Fontes CMGA, Goyal A. Functional and structural characterization of family 6 carbohydrate-binding module (CtCBM6A) of Clostridium thermocellum α-L-arabinofuranosidase. BIOCHEMISTRY (MOSCOW) 2013; 78:1272-9. [DOI: 10.1134/s0006297913110072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Khan MIM, Sajjad M, Sadaf S, Zafar R, Niazi UHK, Akhtar MW. The nature of the carbohydrate binding module determines the catalytic efficiency of xylanase Z of Clostridium thermocellum. J Biotechnol 2013; 168:403-8. [PMID: 24095983 DOI: 10.1016/j.jbiotec.2013.09.010] [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: 07/01/2013] [Revised: 08/22/2013] [Accepted: 09/12/2013] [Indexed: 11/30/2022]
Abstract
Xylanase Z of Clostridium thermocellum exists as a complex in the cellulosome with N-terminus feruloyl esterase, a carbohydrate binding module (CBM6) and a dockerin domain. To study the role of the binding modules on the activity of XynZ, different variants with the CBM6 attached to the catalytic domain at its C-terminal (XynZ-CB) and N-terminal (XynZ-BC), and the CBM22 attached at N-terminus (XynZ-B'C) were expressed in Escherichia coli at levels around 30% of the total cell proteins. The activities of XynZ-BC, XynZ-CB and XynZ-B'C were 4200, 4180 and 20,700U μM(-1) against birchwood xylan, respectively. Substrate binding studies showed that in case of XynZ-BC and XynZ-CB the substrate birchwood xylan remaining unbound were 51 and 52%, respectively, whereas in the case of XynZ-B'C the substrate remaining unbound was 39% under the assay conditions used. The molecular docking studies showed that the binding site of CBM22 in XynZ-B'C is more exposed and thus available for substrate binding as compared to the tunnel shape binding pocket produced in XynZ-BC and thus hindering the substrate binding. The substrate binding data for the two constructs are in agreement with this explanation.
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27
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Solution structure, dynamics and binding studies of a family 11 carbohydrate-binding module from Clostridium thermocellum (CtCBM11). Biochem J 2013; 451:289-300. [PMID: 23356867 DOI: 10.1042/bj20120627] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Non-catalytic cellulosomal CBMs (carbohydrate-binding modules) are responsible for increasing the catalytic efficiency of cellulosic enzymes by selectively putting the substrate (a wide range of poly- and oligo-saccharides) and enzyme into close contact. In the present study we carried out an atomistic rationalization of the molecular determinants of ligand specificity for a family 11 CBM from thermophilic Clostridium thermocellum [CtCBM11 (C. thermocellum CBM11)], based on a NMR and molecular modelling approach. We have determined the NMR solution structure of CtCBM11 at 25°C and 50°C and derived information on the residues of the protein that are involved in ligand recognition and on the influence of the length of the saccharide chain on binding. We obtained models of the CtCBM11-cellohexaose and CtCBM11-cellotetraose complexes by docking in accordance with the NMR experimental data. Specific ligand-protein CH-π and Van der Waals interactions were found to be determinant for the stability of the complexes and for defining specificity. Using the order parameters derived from backbone dynamics analysis in the presence and absence of ligand and at 25°C and 50°C, we determined that the protein's backbone conformational entropy is slightly positive. This data in combination with the negative binding entropy calculated from ITC (isothermal titration calorimetry) studies supports a selection mechanism where a rigid protein selects a defined oligosaccharide conformation.
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28
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Luís AS, Venditto I, Temple MJ, Rogowski A, Baslé A, Xue J, Knox JP, Prates JAM, Ferreira LMA, Fontes CMGA, Najmudin S, Gilbert HJ. Understanding how noncatalytic carbohydrate binding modules can display specificity for xyloglucan. J Biol Chem 2012; 288:4799-809. [PMID: 23229556 PMCID: PMC3576085 DOI: 10.1074/jbc.m112.432781] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Plant biomass is central to the carbon cycle and to environmentally sustainable industries exemplified by the biofuel sector. Plant cell wall degrading enzymes generally contain noncatalytic carbohydrate binding modules (CBMs) that fulfil a targeting function, which enhances catalysis. CBMs that bind β-glucan chains often display broad specificity recognizing β1,4-glucans (cellulose), β1,3-β1,4-mixed linked glucans and xyloglucan, a β1,4-glucan decorated with α1,6-xylose residues, by targeting structures common to the three polysaccharides. Thus, CBMs that recognize xyloglucan target the β1,4-glucan backbone and only accommodate the xylose decorations. Here we show that two closely related CBMs, CBM65A and CBM65B, derived from EcCel5A, a Eubacterium cellulosolvens endoglucanase, bind to a range of β-glucans but, uniquely, display significant preference for xyloglucan. The structures of the two CBMs reveal a β-sandwich fold. The ligand binding site comprises the β-sheet that forms the concave surface of the proteins. Binding to the backbone chains of β-glucans is mediated primarily by five aromatic residues that also make hydrophobic interactions with the xylose side chains of xyloglucan, conferring the distinctive specificity of the CBMs for the decorated polysaccharide. Significantly, and in contrast to other CBMs that recognize β-glucans, CBM65A utilizes different polar residues to bind cellulose and mixed linked glucans. Thus, Gln106 is central to cellulose recognition, but is not required for binding to mixed linked glucans. This report reveals the mechanism by which β-glucan-specific CBMs can distinguish between linear and mixed linked glucans, and show how these CBMs can exploit an extensive hydrophobic platform to target the side chains of decorated β-glucans.
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Affiliation(s)
- Ana S Luís
- CIISA, Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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29
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Wheatley RW, Zheng RB, Richards MR, Lowary TL, Ng KKS. Tetrameric structure of the GlfT2 galactofuranosyltransferase reveals a scaffold for the assembly of mycobacterial Arabinogalactan. J Biol Chem 2012; 287:28132-43. [PMID: 22707726 DOI: 10.1074/jbc.m112.347484] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Biosynthesis of the mycobacterial cell wall relies on the activities of many enzymes, including several glycosyltransferases (GTs). The polymerizing galactofuranosyltransferase GlfT2 (Rv3808c) synthesizes the bulk of the galactan portion of the mycolyl-arabinogalactan complex, which is the largest component of the mycobacterial cell wall. We used x-ray crystallography to determine the 2.45-Å resolution crystal structure of GlfT2, revealing an unprecedented multidomain structure in which an N-terminal β-barrel domain and two primarily α-helical C-terminal domains flank a central GT-A domain. The kidney-shaped protomers assemble into a C(4)-symmetric homotetramer with an open central core and a surface containing exposed hydrophobic and positively charged residues likely involved with membrane binding. The structure of a 3.1-Å resolution complex of GlfT2 with UDP reveals a distinctive mode of nucleotide recognition. In addition, models for the binding of UDP-galactofuranose and acceptor substrates in combination with site-directed mutagenesis and kinetic studies suggest a mechanism that explains the unique ability of GlfT2 to generate alternating β-(1→5) and β-(1→6) glycosidic linkages using a single active site. The topology imposed by docking a tetrameric assembly onto a membrane bilayer also provides novel insights into aspects of processivity and chain length regulation in this and possibly other polymerizing GTs.
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Affiliation(s)
- Robert W Wheatley
- Alberta Glycomics Centre, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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30
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Cao R, Jin Y, Xu D. Recognition of Cello-Oligosaccharides by CBM17 from Clostridium cellulovorans: Molecular Dynamics Simulation. J Phys Chem B 2012; 116:6087-96. [DOI: 10.1021/jp3010647] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ruyin Cao
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P. R. China
| | - Yongdong Jin
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P. R. China
| | - Dingguo Xu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P. R. China
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31
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32
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Pickens LB, Sawaya MR, Rasool H, Pashkov I, Yeates TO, Tang Y. Structural and biochemical characterization of the salicylyl-acyltranferase SsfX3 from a tetracycline biosynthetic pathway. J Biol Chem 2011; 286:41539-41551. [PMID: 21965680 PMCID: PMC3308865 DOI: 10.1074/jbc.m111.299859] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 09/28/2011] [Indexed: 11/06/2022] Open
Abstract
SsfX3 is a GDSL family acyltransferase that transfers salicylate to the C-4 hydroxyl of a tetracycline intermediate in the penultimate step during biosynthesis of the anticancer natural product SF2575. The C-4 salicylate takes the place of the more common C-4 dimethylamine functionality, making SsfX3 the first acyltransferase identified to act on a tetracycline substrate. The crystal structure of SsfX3 was determined at 2.5 Å, revealing two distinct domains as follows: an N-terminal β-sandwich domain that resembles a carbohydrate-binding module, and a C-terminal catalytic domain that contains the atypical α/β-hydrolase fold found in the GDSL hydrolase family of enzymes. The active site lies at one end of a large open binding pocket, which is spatially defined by structural elements from both the N- and C-terminal domains. Mutational analysis in the putative substrate binding pocket identified residues from both domains that are important for binding the acyl donor and acceptor. Furthermore, removal of the N-terminal carbohydrate-binding module-like domain rendered the stand-alone α/β-hydrolase domain inactive. The additional noncatalytic module is therefore proposed to be required to define the binding pocket and provide sufficient interactions with the spatially extended tetracyclic substrate. SsfX3 was also demonstrated to accept a variety of non-native acyl groups. This relaxed substrate specificity toward the acyl donor allowed the chemoenzymatic biosynthesis of C-4-modified analogs of the immediate precursor to the bioactive SF2575; these were used to assay the structure activity relationships at the C-4 position.
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Affiliation(s)
- Lauren B Pickens
- Departments of Chemical and Biomolecular Engineering, Los Angeles, California 90095
| | - Michael R Sawaya
- Departments of Chemistry and Biochemistry, Los Angeles, California 90095; Department of Howard Hughes Medical Institute, and UCLA-DOE Institute for Genomics and Proteomics, UCLA, Los Angeles, California 90095
| | - Huma Rasool
- Departments of Chemical and Biomolecular Engineering, Los Angeles, California 90095
| | - Inna Pashkov
- Departments of Chemistry and Biochemistry, Los Angeles, California 90095
| | - Todd O Yeates
- Departments of Chemistry and Biochemistry, Los Angeles, California 90095; Department of Molecular Biology Institute, Los Angeles, California 90095
| | - Yi Tang
- Departments of Chemical and Biomolecular Engineering, Los Angeles, California 90095; Departments of Chemistry and Biochemistry, Los Angeles, California 90095; Department of Molecular Biology Institute, Los Angeles, California 90095.
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33
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Montanier CY, Correia MAS, Flint JE, Zhu Y, Baslé A, McKee LS, Prates JAM, Polizzi SJ, Coutinho PM, Lewis RJ, Henrissat B, Fontes CMGA, Gilbert HJ. A novel, noncatalytic carbohydrate-binding module displays specificity for galactose-containing polysaccharides through calcium-mediated oligomerization. J Biol Chem 2011; 286:22499-509. [PMID: 21454512 PMCID: PMC3121395 DOI: 10.1074/jbc.m110.217372] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 03/14/2011] [Indexed: 01/25/2023] Open
Abstract
The enzymic degradation of plant cell walls plays a central role in the carbon cycle and is of increasing environmental and industrial significance. The catalytic modules of enzymes that catalyze this process are generally appended to noncatalytic carbohydrate-binding modules (CBMs). CBMs potentiate the rate of catalysis by bringing their cognate enzymes into intimate contact with the target substrate. A powerful plant cell wall-degrading system is the Clostridium thermocellum multienzyme complex, termed the "cellulosome." Here, we identify a novel CBM (CtCBM62) within the large C. thermocellum cellulosomal protein Cthe_2193 (defined as CtXyl5A), which establishes a new CBM family. Phylogenetic analysis of CBM62 members indicates that a circular permutation occurred within the family. CtCBM62 binds to d-galactose and l-arabinopyranose in either anomeric configuration. The crystal structures of CtCBM62, in complex with oligosaccharides containing α- and β-galactose residues, show that the ligand-binding site in the β-sandwich protein is located in the loops that connect the two β-sheets. Specificity is conferred through numerous interactions with the axial O4 of the target sugars, a feature that distinguishes galactose and arabinose from the other major sugars located in plant cell walls. CtCBM62 displays tighter affinity for multivalent ligands compared with molecules containing single galactose residues, which is associated with precipitation of these complex carbohydrates. These avidity effects, which confer the targeting of polysaccharides, are mediated by calcium-dependent oligomerization of the CBM.
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Affiliation(s)
- Cedric Y. Montanier
- the Institute for Cell and Molecular Biosciences, Newcastle University, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Márcia A. S. Correia
- the Institute for Cell and Molecular Biosciences, Newcastle University, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - James E. Flint
- the Institute for Cell and Molecular Biosciences, Newcastle University, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Yanping Zhu
- From the Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- the Institute for Cell and Molecular Biosciences, Newcastle University, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712, and
| | - Arnaud Baslé
- the Institute for Cell and Molecular Biosciences, Newcastle University, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Lauren S. McKee
- the Institute for Cell and Molecular Biosciences, Newcastle University, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712, and
| | - José A. M. Prates
- From the Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Samuel J. Polizzi
- the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602-7229
| | - Pedro M. Coutinho
- the Architecture et Fonction des Macromolécules Biologiques, UMR6098, CNRS, Universités Aix-Marseille I and II, 163 Avenue de Luminy, 13288 Marseille, France
| | - Richard J. Lewis
- the Institute for Cell and Molecular Biosciences, Newcastle University, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Bernard Henrissat
- the Architecture et Fonction des Macromolécules Biologiques, UMR6098, CNRS, Universités Aix-Marseille I and II, 163 Avenue de Luminy, 13288 Marseille, France
| | - Carlos M. G. A. Fontes
- From the Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Harry J. Gilbert
- the Institute for Cell and Molecular Biosciences, Newcastle University, Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712, and
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34
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Correia MAS, Mazumder K, Brás JLA, Firbank SJ, Zhu Y, Lewis RJ, York WS, Fontes CMGA, Gilbert HJ. Structure and function of an arabinoxylan-specific xylanase. J Biol Chem 2011; 286:22510-20. [PMID: 21378160 DOI: 10.1074/jbc.m110.217315] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The enzymatic degradation of plant cell walls plays a central role in the carbon cycle and is of increasing environmental and industrial significance. The enzymes that catalyze this process include xylanases that degrade xylan, a β-1,4-xylose polymer that is decorated with various sugars. Although xylanases efficiently hydrolyze unsubstituted xylans, these enzymes are unable to access highly decorated forms of the polysaccharide, such as arabinoxylans that contain arabinofuranose decorations. Here, we show that a Clostridium thermocellum enzyme, designated CtXyl5A, hydrolyzes arabinoxylans but does not attack unsubstituted xylans. Analysis of the reaction products generated by CtXyl5A showed that all the oligosaccharides contain an O3 arabinose linked to the reducing end xylose. The crystal structure of the catalytic module (CtGH5) of CtXyl5A, appended to a family 6 noncatalytic carbohydrate-binding module (CtCBM6), showed that CtGH5 displays a canonical (α/β)(8)-barrel fold with the substrate binding cleft running along the surface of the protein. The catalytic apparatus is housed in the center of the cleft. Adjacent to the -1 subsite is a pocket that could accommodate an l-arabinofuranose-linked α-1,3 to the active site xylose, which is likely to function as a key specificity determinant. CtCBM6, which adopts a β-sandwich fold, recognizes the termini of xylo- and gluco-configured oligosaccharides, consistent with the pocket topology displayed by the ligand-binding site. In contrast to typical modular glycoside hydrolases, there is an extensive hydrophobic interface between CtGH5 and CtCBM6, and thus the two modules cannot function as independent entities.
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Affiliation(s)
- Márcia A S Correia
- Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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35
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Funane K, Kawabata Y, Suzuki R, Kim YM, Kang HK, Suzuki N, Fujimoto Z, Kimura A, Kobayashi M. Deletion analysis of regions at the C-terminal part of cycloisomaltooligosaccharide glucanotransferase from Bacillus circulans T-3040. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:428-34. [PMID: 21193067 DOI: 10.1016/j.bbapap.2010.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2010] [Revised: 12/01/2010] [Accepted: 12/19/2010] [Indexed: 11/18/2022]
Abstract
Cycloisomaltooligosaccharide glucanotransferase (CITase) belongs to glycoside hydrolase family 66. According to the sequence alignment of enzymes in the same family, we divided the structure of CITase into five regions from the N terminus to the C terminus: an N-terminal conserved region (Ser1-Gly403), an insertion region (R1; Tyr404-Tyr492), two conserved regions (R2; Glu493-Ser596 and R3; Gly597-Met700), and a C-terminal variable region (R4; Lys701-Ser934). CITase catalyzes the synthesis of cycloisomaltooligosaccharides (CIs) with 7-17 glucose units (CI-7 to CI-17) from dextran. In order to clarify the functions of these C-terminal regions (R1-R4), we constructed 15 deletion mutant enzymes. M123Δ (R4-deleted), MΔ234 (R1-deleted), and MΔ23Δ (R1/R4-deleted) catalyzed CI synthesis, but other mutants were inactive. M123Δ, MΔ234, and MΔ23Δ increased their K(m) values against dextran 40. The wild-type enzyme and M123Δ produced CI-8 predominantly, but MΔ234 and MΔ23Δ lost CI-8 production specificity. The k(cat) values of MΔ234 and MΔ23Δ decreased, and these mutants showed narrowed temperature and pH stability ranges. Our deletion analysis suggests that (i) R2 and R3 are crucial for CITase to generate an active form; (ii) both R1 and R4 contribute to substrate binding; and (iii) R1 also contributes to preference of CI-8 production and enzyme stability.
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Affiliation(s)
- Kazumi Funane
- National Agriculture and Food Research Organization, Tsukuba 305-8642, Japan.
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36
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Cid M, Pedersen HL, Kaneko S, Coutinho PM, Henrissat B, Willats WGT, Boraston AB. Recognition of the helical structure of beta-1,4-galactan by a new family of carbohydrate-binding modules. J Biol Chem 2010; 285:35999-6009. [PMID: 20826814 PMCID: PMC2975222 DOI: 10.1074/jbc.m110.166330] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 08/23/2010] [Indexed: 11/06/2022] Open
Abstract
The microbial enzymes that depolymerize plant cell wall polysaccharides, ultimately promoting energy liberation and carbon recycling, are typically complex in their modularity and often contain carbohydrate-binding modules (CBMs). Here, through analysis of an unknown module from a Thermotoga maritima endo-β-1,4-galactanase, we identify a new family of CBMs that are most frequently found appended to proteins with β-1,4-galactanase activity. Polysaccharide microarray screening, immunofluorescence microscopy, and biochemical analysis of the isolated module demonstrate the specificity of the module, here called TmCBM61, for β-1,4-linked galactose-containing ligands, making it the founding member of family CBM61. The ultra-high resolution X-ray crystal structures of TmCBM61 (0.95 and 1.4 Å resolution) in complex with β-1,4-galactotriose reveal the molecular basis of the specificity of the CBM for β-1,4-galactan. Analysis of these structures provides insight into the recognition of an unexpected helical galactan conformation through a mode of binding that resembles the recognition of starch.
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Affiliation(s)
- Melissa Cid
- From the Department Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
| | - Henriette Lodberg Pedersen
- the Faculty of Life Sciences, University of Copenhagen, Bülowsvej 17, 1870 Frederiksberg C, Copenhagen, Denmark
| | - Satoshi Kaneko
- the Food Biotechnology Division, National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan, and
| | - Pedro M. Coutinho
- the Laboratoire d'Architecture et de Fonction des Macromolécules Biologiques, UMR6098 CNRS, Universités Aix-Marseille I and II, Case 932, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France
| | - Bernard Henrissat
- the Laboratoire d'Architecture et de Fonction des Macromolécules Biologiques, UMR6098 CNRS, Universités Aix-Marseille I and II, Case 932, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France
| | - William G. T. Willats
- the Faculty of Life Sciences, University of Copenhagen, Bülowsvej 17, 1870 Frederiksberg C, Copenhagen, Denmark
| | - Alisdair B. Boraston
- From the Department Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
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37
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Montanier C, Flint JE, Bolam DN, Xie H, Liu Z, Rogowski A, Weiner DP, Ratnaparkhe S, Nurizzo D, Roberts SM, Turkenburg JP, Davies GJ, Gilbert HJ. Circular permutation provides an evolutionary link between two families of calcium-dependent carbohydrate binding modules. J Biol Chem 2010; 285:31742-54. [PMID: 20659893 PMCID: PMC2951246 DOI: 10.1074/jbc.m110.142133] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/13/2010] [Indexed: 11/06/2022] Open
Abstract
The microbial deconstruction of the plant cell wall is a critical biological process, which also provides important substrates for environmentally sustainable industries. Enzymes that hydrolyze the plant cell wall generally contain non-catalytic carbohydrate binding modules (CBMs) that contribute to plant cell wall degradation. Here we report the biochemical properties and crystal structure of a family of CBMs (CBM60) that are located in xylanases. Uniquely, the proteins display broad ligand specificity, targeting xylans, galactans, and cellulose. Some of the CBM60s display enhanced affinity for their ligands through avidity effects mediated by protein dimerization. The crystal structure of vCBM60, displays a β-sandwich with the ligand binding site comprising a broad cleft formed by the loops connecting the two β-sheets. Ligand recognition at site 1 is, exclusively, through hydrophobic interactions, whereas binding at site 2 is conferred by polar interactions between a protein-bound calcium and the O2 and O3 of the sugar. The observation, that ligand recognition at site 2 requires only a β-linked sugar that contains equatorial hydroxyls at C2 and C3, explains the broad ligand specificity displayed by vCBM60. The ligand-binding apparatus of vCBM60 displays remarkable structural conservation with a family 36 CBM (CBM36); however, the residues that contribute to carbohydrate recognition are derived from different regions of the two proteins. Three-dimensional structure-based sequence alignments reveal that CBM36 and CBM60 are related by circular permutation. The biological and evolutionary significance of the mechanism of ligand recognition displayed by family 60 CBMs is discussed.
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Affiliation(s)
- Cedric Montanier
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - James E. Flint
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - David N. Bolam
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Hefang Xie
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Ziyuan Liu
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Artur Rogowski
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | | | - Supriya Ratnaparkhe
- the Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-4712
| | - Didier Nurizzo
- the European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, F-38043 Grenoble Cedex, France
| | - Shirley M. Roberts
- the York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, United Kingdom, and
| | - Johan P. Turkenburg
- the York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, United Kingdom, and
| | - Gideon J. Davies
- the York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, United Kingdom, and
| | - Harry J. Gilbert
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
- the Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-4712
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38
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Yeh AP, Abdubek P, Astakhova T, Axelrod HL, Bakolitsa C, Cai X, Carlton D, Chen C, Chiu HJ, Chiu M, Clayton T, Das D, Deller MC, Duan L, Ellrott K, Farr CL, Feuerhelm J, Grant JC, Grzechnik A, Han GW, Jaroszewski L, Jin KK, Klock HE, Knuth MW, Kozbial P, Krishna SS, Kumar A, Lam WW, Marciano D, McMullan D, Miller MD, Morse AT, Nigoghossian E, Nopakun A, Okach L, Puckett C, Reyes R, Tien HJ, Trame CB, van den Bedem H, Weekes D, Wooten T, Xu Q, Hodgson KO, Wooley J, Elsliger MA, Deacon AM, Godzik A, Lesley SA, Wilson IA. Structure of Bacteroides thetaiotaomicron BT2081 at 2.05 Å resolution: the first structural representative of a new protein family that may play a role in carbohydrate metabolism. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1287-96. [PMID: 20944224 PMCID: PMC2954218 DOI: 10.1107/s1744309110028228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 07/14/2010] [Indexed: 03/06/2023]
Abstract
BT2081 from Bacteroides thetaiotaomicron (GenBank accession code NP_810994.1) is a member of a novel protein family consisting of over 160 members, most of which are found in the different classes of Bacteroidetes. Genome-context analysis lends support to the involvement of this family in carbohydrate metabolism, which plays a key role in B. thetaiotaomicron as a predominant bacterial symbiont in the human distal gut microbiome. The crystal structure of BT2081 at 2.05 Å resolution represents the first structure from this new protein family. BT2081 consists of an N-terminal domain, which adopts a β-sandwich immunoglobulin-like fold, and a larger C-terminal domain with a β-sandwich jelly-roll fold. Structural analyses reveal that both domains are similar to those found in various carbohydrate-active enzymes. The C-terminal β-jelly-roll domain contains a potential carbohydrate-binding site that is highly conserved among BT2081 homologs and is situated in the same location as the carbohydrate-binding sites that are found in structurally similar glycoside hydrolases (GHs). However, in BT2081 this site is partially occluded by surrounding loops, which results in a deep solvent-accessible pocket rather than a shallower solvent-exposed cleft.
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Affiliation(s)
- Andrew P. Yeh
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Polat Abdubek
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Tamara Astakhova
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Herbert L. Axelrod
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Constantina Bakolitsa
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Xiaohui Cai
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Dennis Carlton
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Connie Chen
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Hsiu-Ju Chiu
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Michelle Chiu
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Thomas Clayton
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Debanu Das
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Marc C. Deller
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Lian Duan
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Kyle Ellrott
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Carol L. Farr
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Julie Feuerhelm
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Joanna C. Grant
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Anna Grzechnik
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Gye Won Han
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Lukasz Jaroszewski
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Kevin K. Jin
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Heath E. Klock
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Mark W. Knuth
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Piotr Kozbial
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - S. Sri Krishna
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Abhinav Kumar
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Winnie W. Lam
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - David Marciano
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Daniel McMullan
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Mitchell D. Miller
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Andrew T. Morse
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Edward Nigoghossian
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Amanda Nopakun
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Linda Okach
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Christina Puckett
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Ron Reyes
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Henry J. Tien
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Christine B. Trame
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Henry van den Bedem
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Dana Weekes
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Tiffany Wooten
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Qingping Xu
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Keith O. Hodgson
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Photon Science, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - John Wooley
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Marc-André Elsliger
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Ashley M. Deacon
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Adam Godzik
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Scott A. Lesley
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Ian A. Wilson
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
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39
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Yoshida S, Hespen CW, Beverly RL, Mackie RI, Cann IKO. Domain analysis of a modular alpha-L-Arabinofuranosidase with a unique carbohydrate binding strategy from the fiber-degrading bacterium Fibrobacter succinogenes S85. J Bacteriol 2010; 192:5424-36. [PMID: 20709893 PMCID: PMC2950500 DOI: 10.1128/jb.00503-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Accepted: 08/03/2010] [Indexed: 11/20/2022] Open
Abstract
Family 43 glycoside hydrolases (GH43s) are known to exhibit various activities involved in hemicellulose hydrolysis. Thus, these enzymes contribute to efficient plant cell wall degradation, a topic of much interest for biofuel production. In this study, we characterized a unique GH43 protein from Fibrobacter succinogenes S85. The recombinant protein showed α-l-arabinofuranosidase activity, specifically with arabinoxylan. The enzyme is, therefore, an arabinoxylan arabinofuranohydrolase (AXH). The F. succinogenes AXH (FSUAXH1) is a modular protein that is composed of a signal peptide, a GH43 catalytic module, a unique β-sandwich module (XX domain), a family 6 carbohydrate-binding module (CBM6), and F. succinogenes-specific paralogous module 1 (FPm-1). Truncational analysis and site-directed mutagenesis of the protein revealed that the GH43 domain/XX domain constitute a new form of carbohydrate-binding module and that residue Y484 in the XX domain is essential for binding to arabinoxylan, although protein structural analyses may be required to confirm some of the observations. Kinetic studies demonstrated that the Y484A mutation leads to a higher k(cat) for a truncated derivative of FSUAXH1 composed of only the GH43 catalytic module and the XX domain. However, an increase in the K(m) for arabinoxylan led to a 3-fold decrease in catalytic efficiency. Based on the knowledge that most XX domains are found only in GH43 proteins, the evolutionary relationships within the GH43 family were investigated. These analyses showed that in GH43 members with a XX domain, the two modules have coevolved and that the length of a loop within the XX domain may serve as an important determinant of substrate specificity.
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Affiliation(s)
- Shosuke Yoshida
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
| | - Charles W. Hespen
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
| | - Robert L. Beverly
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
| | - Roderick I. Mackie
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
| | - Isaac K. O. Cann
- Energy Biosciences Institute, Institute for Genomic Biology, Department of Biochemistry, Department of Microbiology, Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801
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40
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Su X, Agarwal V, Dodd D, Bae B, Mackie RI, Nair SK, Cann IKO. Mutational insights into the roles of amino acid residues in ligand binding for two closely related family 16 carbohydrate binding modules. J Biol Chem 2010; 285:34665-76. [PMID: 20739280 DOI: 10.1074/jbc.m110.168302] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carbohydrate binding modules (CBMs) are specialized proteins that bind to polysaccharides and oligosaccharides. Caldanaerobius polysaccharolyticus Man5ACBM16-1/CBM16-2 bind to glucose-, mannose-, and glucose/mannose-configured substrates. The crystal structures of the two proteins represent the only examples in CBM family 16, and studies that evaluate the roles of amino acid residues in ligand binding in this family are lacking. In this study, we probed the roles of amino acids (selected based on CBM16-1/ligand co-crystal structures) on substrate binding. Two tryptophan (Trp-20 and Trp-125) and two glutamine (Gln-81 and Gln-93) residues are shown to be critical in ligand binding. Additionally, several polar residues that flank the critical residues also contribute to ligand binding. The CBM16-1 Q121E mutation increased affinity for all substrates tested, whereas the Q21G and N97R mutants exhibited decreased substrate affinity. We solved CBM/substrate co-crystal structures to elucidate the molecular basis of the increased substrate binding by CBM16-1 Q121E. The Gln-121, Gln-21, and Asn-97 residues can be manipulated to fine-tune ligand binding by the Man5A CBMs. Surprisingly, none of the eight residues investigated was absolutely conserved in CBM family 16. Thus, the critical residues in the Man5A CBMs are either not essential for substrate binding in the other members of this family or the two CBMs are evolutionarily distinct from the members available in the current protein database. Man5A is dependent on its CBMs for robust activity, and insights from this study should serve to enhance our understanding of the interdependence of its catalytic and substrate binding modules.
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Affiliation(s)
- Xiaoyun Su
- Energy Biosciences Institute, Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801, USA
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41
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Correia MAS, Abbott DW, Gloster TM, Fernandes VO, Prates JAM, Montanier C, Dumon C, Williamson MP, Tunnicliffe RB, Liu Z, Flint JE, Davies GJ, Henrissat B, Coutinho PM, Fontes CMGA, Gilbert HJ. Signature active site architectures illuminate the molecular basis for ligand specificity in family 35 carbohydrate binding module. Biochemistry 2010; 49:6193-205. [PMID: 20496884 DOI: 10.1021/bi1006139] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The deconstruction of the plant cell wall is an important biological process that is attracting considerable industrial interest, particularly in the bioenergy sector. Enzymes that attack the plant cell wall generally contain one or more noncatalytic carbohydrate binding modules (CBMs) that play an important targeting function. While CBMs that bind to the backbones of plant structural polysaccharides have been widely described, modules that recognize components of the vast array of decorations displayed on these polymers have been relatively unexplored. Here we show that a family 35 CBM member (CBM35), designated CtCBM35-Gal, binds to alpha-D-galactose (Gal) and, within the context of the plant cell wall, targets the alpha-1,6-Gal residues of galactomannan but not the beta-D-Gal residues in xyloglucan. The crystal structure of CtCBM35-Gal reveals a canonical beta-sandwich fold. Site-directed mutagenesis studies showed that the ligand is accommodated within the loops that connect the two beta-sheets. Although the ligand binding site of the CBM displays significant structural similarity with calcium-dependent CBM35s that target uronic acids, subtle differences in the conformation of conserved residues in the ligand binding site lead to the loss of metal binding and uronate recognition. A model is proposed in which the orientation of the pair of aromatic residues that interact with the two faces of the Gal pyranose ring plays a pivotal role in orientating the axial O4 atom of the ligand toward Asn140, which is invariant in CBM35. The ligand recognition site of exo-CBM35s (CBM35-Gal and the uronic acid binding CBM35s) appears to overlap with that of CBM35-Man, which binds to the internal regions of mannan, a beta-polymer of mannose. Using site-directed mutagenesis, we show that although there is conservation of several functional residues within the binding sites of endo- and exo-CBM35s, the endo-CBM does not utilize Asn113 (equivalent to Asn140 in CBM35-Gal) in mannan binding, despite the importance of the equivalent residue in ligand recognition across the CBM35 and CBM6 landscape. The data presented in this report are placed within a wider phylogenetic context for the CBM35 family.
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Affiliation(s)
- Márcia A S Correia
- CIISA, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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42
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Gilbert HJ. The biochemistry and structural biology of plant cell wall deconstruction. PLANT PHYSIOLOGY 2010; 153:444-55. [PMID: 20406913 PMCID: PMC2879781 DOI: 10.1104/pp.110.156646] [Citation(s) in RCA: 217] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 04/17/2010] [Indexed: 05/18/2023]
Affiliation(s)
- Harry J Gilbert
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA.
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43
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Biochemical and domain analyses of FSUAxe6B, a modular acetyl xylan esterase, identify a unique carbohydrate binding module in Fibrobacter succinogenes S85. J Bacteriol 2009; 192:483-93. [PMID: 19897648 DOI: 10.1128/jb.00935-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acetyl xylan esterase (EC 3.1.1.72) is a member of a set of enzymes required to depolymerize hemicellulose, especially xylan that is composed of a main chain of beta-1,4-linked xylopyranoside residues decorated with acetyl side groups. Fibrobacter succinogenes S85 Axe6B (FSUAxe6B) is an acetyl xylan esterase encoded in the genome of this rumen bacterium. The enzyme is a modular protein comprised of an esterase domain, a carbohydrate-binding module, and a region of unknown function. Sequences that are homologous to the region of unknown function are paralogously distributed, thus far, only in F. succinogenes. Therefore, the sequences were designated Fibrobacter succinogenes-specific paralogous module 1 (FPm-1). The FPm-1s are associated with at least 24 polypeptides in the genome of F. succinogenes S85. A bioinformatics search showed that most of the FPm-1-appended polypeptides are putative carbohydrate-active enzymes, suggesting a potential role in carbohydrate metabolism. Truncational analysis of FSUAxe6B, together with catalytic and substrate binding studies, has allowed us to delineate the functional modules in the polypeptide. The N-terminal half of FSUAxe6B harbors the activity that cleaves side chain acetyl groups from xylan-like substrates, and the binding of insoluble xylan was determined to originate from FPm-1. Site-directed mutagenesis studies of highly conserved active-site residues in the esterase domain suggested that the esterase activity is derived from a tetrad composed of Ser(44), His(273), Glu(194), and Asp(270), with both Glu(194) and Asp(270) functioning as helper acids, instead of a single carboxylate residue proposed to initiate catalysis.
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44
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Correia MÃA, Pires VM, Gilbert HJ, Bolam DN, Fernandes VÃO, Alves VD, Prates JA, Ferreira LM, Fontes CM. Family 6 carbohydrate-binding modules display multiple β1,3-linked glucan-specific binding interfaces. FEMS Microbiol Lett 2009; 300:48-57. [DOI: 10.1111/j.1574-6968.2009.01764.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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45
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Abbott DW, Ficko-Blean E, van Bueren AL, Rogowski A, Cartmell A, Coutinho PM, Henrissat B, Gilbert HJ, Boraston AB. Analysis of the Structural and Functional Diversity of Plant Cell Wall Specific Family 6 Carbohydrate Binding Modules. Biochemistry 2009; 48:10395-404. [DOI: 10.1021/bi9013424] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D. Wade Abbott
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6, Canada
| | - Elizabeth Ficko-Blean
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6, Canada
| | - Alicia Lammerts van Bueren
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6, Canada
| | - Artur Rogowski
- School of Biomedical Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, U.K
| | - Alan Cartmell
- School of Biomedical Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, U.K
| | - Pedro M. Coutinho
- Laboratoire d’Architecture et de Fonction des macromolécules Biologiques, IBSM, CNRS Marseille and University Aix-Marseille I & II, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Bernard Henrissat
- Laboratoire d’Architecture et de Fonction des macromolécules Biologiques, IBSM, CNRS Marseille and University Aix-Marseille I & II, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Harry J. Gilbert
- School of Biomedical Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, U.K
| | - Alisdair B. Boraston
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6, Canada
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46
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Ficko-Blean E, Boraston AB. N-acetylglucosamine recognition by a family 32 carbohydrate-binding module from Clostridium perfringens NagH. J Mol Biol 2009; 390:208-20. [PMID: 19422833 PMCID: PMC2937040 DOI: 10.1016/j.jmb.2009.04.066] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 04/24/2009] [Accepted: 04/27/2009] [Indexed: 10/20/2022]
Abstract
Many carbohydrate-active enzymes have complex architectures comprising multiple modules that may be involved in catalysis, carbohydrate binding, or protein-protein interactions. Carbohydrate-binding modules (CBMs) are a common ancillary module whose function is to promote the adherence of the complete enzyme to carbohydrate substrates. CBM family 32 has been proposed to be one of the most diverse CBM families classified to date, yet all of the structurally characterized CBM32s thus far recognize galactose-based ligands. Here, we report a unique binding specificity and mode of ligand binding for a family 32 CBM. NagHCBM32-2 is one of four CBM32 modules in NagH, a family 84 glycoside hydrolase secreted by Clostridium perfringens. NagHCBM32-2 has the beta-sandwich scaffold common to members of the family; however, its specificity for N-acetylglucosamine is unusual among CBMs. X-ray crystallographic analysis of the module at resolutions from 1.45 to 2.0 A and in complex with disaccharides reveals that its mode of sugar recognition is quite different from that observed for galactose-specific CBM32s. This study continues to unravel the diversity of CBMs found in family 32 and how these CBMs might impart the carbohydrate-binding specificity to the extracellular glycoside hydrolases in C. perfringens.
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Affiliation(s)
- Elizabeth Ficko-Blean
- Biochemistry & Microbiology, University of Victoria, PO Box 3055 STN CSC, Victoria, BC, V8W 3P6, Canada
| | - Alisdair B. Boraston
- Biochemistry & Microbiology, University of Victoria, PO Box 3055 STN CSC, Victoria, BC, V8W 3P6, Canada
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Michel G, Barbeyron T, Kloareg B, Czjzek M. The family 6 carbohydrate-binding modules have coevolved with their appended catalytic modules toward similar substrate specificity. Glycobiology 2009; 19:615-23. [PMID: 19240276 DOI: 10.1093/glycob/cwp028] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The survey of carbohydrate active enzymes in genomic data uncovered the modular architecture of most of these proteins. Many of the additional modules associated with catalytic modules tightly bind carbohydrates. The primary role of these carbohydrate-binding modules (CBMs) is to enhance the enzymatic activity of the ensemble by bringing their appended catalytic module(s) in intimate contact with their substrates. Biochemical and biophysical approaches have unraveled the subtle interplay of the modules and the structural basis for their ligand specificities, but little attention has been paid to the evolutionary mechanisms leading to the appearance of modular architecture in carbohydrate active enzymes. Focusing on the promiscuous family CBM6 modules, we investigated the evolution of substrate specificities in parallel to that of their respectively appended catalytic modules. An extensive phylogenetic analysis of family CBM6 modules indicates that these noncatalytic modules have diverged into clades which coincide with their substrate selectivity. These data as well as the remarkable congruence of the phylogenetic trees inferred from CBM6s on the one hand and their associated catalytic modules on the other hand show that CBM6s and their associated glycoside hydrolases have coevolved to acquire the same substrate specificity. We also propose an evolutionary scenario explaining the emergence of the modular agarases, by which existent alpha-agarases acquired their agar-binding CBM6 module through a lateral transfer from pre-existing beta-agarases. Altogether, this observed coevolution between CBM6s and their catalytic modules will facilitate the prediction of the substrate specificity of uncharacterized CBM6 modules present in genomic data.
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Affiliation(s)
- Gurvan Michel
- UPMC University Paris 06, 3CNRS, UMR 7139 Marine Plants and Biomolecules, Station Biologique de Roscoff, Roscoff, Bretagne, France.
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48
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Structural analysis of a glycoside hydrolase family 43 arabinoxylan arabinofuranohydrolase in complex with xylotetraose reveals a different binding mechanism compared with other members of the same family. Biochem J 2009; 418:39-47. [PMID: 18980579 DOI: 10.1042/bj20081256] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AXHs (arabinoxylan arabinofuranohydrolases) are alpha-L-arabinofuranosidases that specifically hydrolyse the glycosidic bond between arabinofuranosyl substituents and xylopyranosyl backbone residues of arabinoxylan. Bacillus subtilis was recently shown to produce an AXH that cleaves arabinose units from O-2- or O-3-mono-substituted xylose residues: BsAXH-m2,3 (B. subtilis AXH-m2,3). Crystallographic analysis reveals a two-domain structure for this enzyme: a catalytic domain displaying a five-bladed beta-propeller fold characteristic of GH (glycoside hydrolase) family 43 and a CBM (carbohydrate-binding module) with a beta-sandwich fold belonging to CBM family 6. Binding of substrate to BsAXH-m2,3 is largely based on hydrophobic stacking interactions, which probably allow the positional flexibility needed to hydrolyse both arabinose substituents at the O-2 or O-3 position of the xylose unit. Superposition of the BsAXH-m2,3 structure with known structures of the GH family 43 exo-acting enzymes, beta-xylosidase and alpha-L-arabinanase, each in complex with their substrate, reveals a different orientation of the sugar backbone.
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49
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Evidence that family 35 carbohydrate binding modules display conserved specificity but divergent function. Proc Natl Acad Sci U S A 2009; 106:3065-70. [PMID: 19218457 PMCID: PMC2651348 DOI: 10.1073/pnas.0808972106] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Enzymes that hydrolyze complex carbohydrates play important roles in numerous biological processes that result in the maintenance of marine and terrestrial life. These enzymes often contain noncatalytic carbohydrate binding modules (CBMs) that have important substrate-targeting functions. In general, there is a tight correlation between the ligands recognized by bacterial CBMs and the substrate specificity of the appended catalytic modules. Through high-resolution structural studies, we demonstrate that the architecture of the ligand binding sites of 4 distinct family 35 CBMs (CBM35s), appended to 3 plant cell wall hydrolases and the exo-beta-D-glucosaminidase CsxA, which contributes to the detoxification and metabolism of an antibacterial fungal polysaccharide, is highly conserved and imparts specificity for glucuronic acid and/or Delta4,5-anhydrogalaturonic acid (Delta4,5-GalA). Delta4,5-GalA is released from pectin by the action of pectate lyases and as such acts as a signature molecule for plant cell wall degradation. Thus, the CBM35s appended to the 3 plant cell wall hydrolases, rather than targeting the substrates of the cognate catalytic modules, direct their appended enzymes to regions of the plant that are being actively degraded. Significantly, the CBM35 component of CsxA anchors the enzyme to the bacterial cell wall via its capacity to bind uronic acid sugars. This latter observation reveals an unusual mechanism for bacterial cell wall enzyme attachment. This report shows that the biological role of CBM35s is not dictated solely by their carbohydrate specificities but also by the context of their target ligands.
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50
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Emami K, Topakas E, Nagy T, Henshaw J, Jackson KA, Nelson KE, Mongodin EF, Murray JW, Lewis RJ, Gilbert HJ. Regulation of the xylan-degrading apparatus of Cellvibrio japonicus by a novel two-component system. J Biol Chem 2008; 284:1086-96. [PMID: 18922794 DOI: 10.1074/jbc.m805100200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The microbial degradation of lignocellulose biomass is not only an important biological process but is of increasing industrial significance in the bioenergy sector. The mechanism by which the plant cell wall, an insoluble composite structure, activates the extensive repertoire of microbial hydrolytic enzymes required to catalyze its degradation is poorly understood. Here we have used a transposon mutagenesis strategy to identify a genetic locus, consisting of two genes that modulate the expression of xylan side chain-degrading enzymes in the saprophytic bacterium Cellvibrio japonicus. Significantly, the locus encodes a two-component signaling system, designated AbfS (sensor histidine kinase) and AbfR (response regulator). The AbfR/S two-component system is required to activate the expression of the suite of enzymes that remove the numerous side chains from xylan, but not the xylanases that hydrolyze the beta1,4-linked xylose polymeric backbone of this polysaccharide. Studies on the recombinant sensor domain of AbfS (AbfS(SD)) showed that it bound to decorated xylans and arabinoxylo-oligosaccharides, but not to undecorated xylo-oligosaccharides or other plant structural polysaccharides/oligosaccharides. The crystal structure of AbfS(SD) was determined to a resolution of 2.6A(.) The overall fold of AbfS(SD) is that of a classical Per Arndt Sim domain with a central antiparallel four-stranded beta-sheet flanked by alpha-helices. Our data expand the number of molecules known to bind to the sensor domain of two-component histidine kinases to include complex carbohydrates. The biological rationale for a regulatory system that induces enzymes that remove the side chains of xylan, but not the hydrolases that cleave the backbone of the polysaccharide, is discussed.
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Affiliation(s)
- Kaveh Emami
- Institute for Cell and Molecular Biosciences, Newcastle University, The Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, United Kingdom
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