1
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Vacilotto MM, de Araujo Montalvão L, Pellegrini VDOA, Liberato MV, de Araujo EA, Polikarpov I. Two-domain GH30 xylanase from human gut microbiota as a tool for enzymatic production of xylooligosaccharides: Crystallographic structure and a synergy with GH11 xylosidase. Carbohydr Polym 2024; 337:122141. [PMID: 38710568 DOI: 10.1016/j.carbpol.2024.122141] [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: 12/24/2023] [Revised: 03/21/2024] [Accepted: 04/07/2024] [Indexed: 05/08/2024]
Abstract
Production of value-added compounds and sustainable materials from agro-industrial residues is essential for better waste management and building of circular economy. This includes valorization of hemicellulosic fraction of plant biomass, the second most abundant biopolymer from plant cell walls, aiming to produce prebiotic oligosaccharides, widely explored in food and feed industries. In this work, we conducted biochemical and biophysical characterization of a prokaryotic two-domain R. champanellensis xylanase from glycoside hydrolase (GH) family 30 (RcXyn30A), and evaluated its applicability for XOS production from glucuronoxylan in combination with two endo-xylanases from GH10 and GH11 families and a GH11 xylobiohydrolase. RcXyn30A liberates mainly long monoglucuronylated xylooligosaccharides and is inefficient in cleaving unbranched oligosaccharides. Crystallographic structure of RcXyn30A catalytic domain was solved and refined to 1.37 Å resolution. Structural analysis of the catalytic domain releveled that its high affinity for glucuronic acid substituted xylan is due to the coordination of the substrate decoration by several hydrogen bonds and ionic interactions in the subsite -2. Furthermore, the protein has a larger β5-α5 loop as compared to other GH30 xylanases, which might be crucial for creating an additional aglycone subsite (+3) of the catalytic site. Finally, RcXyn30A activity is synergic to that of GH11 xylobiohydrolase.
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Affiliation(s)
- Milena Moreira Vacilotto
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil
| | - Lucas de Araujo Montalvão
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil
| | | | - Marcelo Vizona Liberato
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil
| | - Evandro Ares de Araujo
- Centro Nacional de Pesquisa em Energia e Materiais, Giuseppe Máximo Scolfaro 10000, 13083-100 Campinas, SP, Brazil
| | - Igor Polikarpov
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil.
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2
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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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3
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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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4
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Bobbili KB, Sivaji N, Priya B, Suguna K, Surolia A. Structure and interactions of the phloem lectin (phloem protein 2) Cus17 from Cucumis sativus. Structure 2023; 31:464-479.e5. [PMID: 36882058 DOI: 10.1016/j.str.2023.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/28/2022] [Accepted: 02/08/2023] [Indexed: 03/08/2023]
Abstract
Phloem protein 2 (PP2) contributes crucially to phloem-based defense in plants by binding to carbohydrates displayed by pathogens. However, its three-dimensional structure and the sugar binding site remained unexplored. Here, we report the crystal structure of the dimeric PP2 Cus17 from Cucumis sativus in its apo form and complexed with nitrobenzene, N-acetyllactosamine, and chitotriose. Each protomer of Cus17 consists of two antiparallel four-stranded twisted β sheets, a β hairpin, and three short helices forming a β sandwich architectural fold. This structural fold has not been previously observed in other plant lectin families. Structure analysis of the lectin-carbohydrate complexes reveals an extended carbohydrate binding site in Cus17, composed mostly of aromatic amino acids. Our studies suggest a highly conserved tertiary structure and a versatile binding site capable of recognizing motifs common to diverse glycans on plant pathogens/pests, which makes the PP2 family suited for phloem-based plant defense.
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Affiliation(s)
- Kishore Babu Bobbili
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Nukathoti Sivaji
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Badma Priya
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Avadhesha Surolia
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India.
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5
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Abstract
N-glycans are common posttranslational modifications on plant proteins, particularly secreted proteins. As plants are the major component of the human diet, and especially in high-fiber diets, plant N-glycans are prominent in the gut. Despite their ubiquity in the gut, the degradation of plant N-glycans by the microbiota has not been described. Here we used a functional analysis approach, coupled to detailed biochemistry and structural biology, to reveal a pathway for the degradation of plant N-glycans encoded by the human gut microbiota. The work reveals insight into how our gut microbes use plant N-glycans as a nutrient source and also provides tools to modify plant N-glycans to mitigate allergic responses, either from foods or plant-expressed therapeutics. The major nutrients available to the human colonic microbiota are complex glycans derived from the diet. To degrade this highly variable mix of sugar structures, gut microbes have acquired a huge array of different carbohydrate-active enzymes (CAZymes), predominantly glycoside hydrolases, many of which have specificities that can be exploited for a range of different applications. Plant N-glycans are prevalent on proteins produced by plants and thus components of the diet, but the breakdown of these complex molecules by the gut microbiota has not been explored. Plant N-glycans are also well characterized allergens in pollen and some plant-based foods, and when plants are used in heterologous protein production for medical applications, the N-glycans present can pose a risk to therapeutic function and stability. Here we use a novel genome association approach for enzyme discovery to identify a breakdown pathway for plant complex N-glycans encoded by a gut Bacteroides species and biochemically characterize five CAZymes involved, including structures of the PNGase and GH92 α-mannosidase. These enzymes provide a toolbox for the modification of plant N-glycans for a range of potential applications. Furthermore, the keystone PNGase also has activity against insect-type N-glycans, which we discuss from the perspective of insects as a nutrient source.
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6
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Lu CH, Chen CC, Yu CS, Liu YY, Liu JJ, Wei ST, Lin YF. MIB2: metal ion-binding site prediction and modeling server. Bioinformatics 2022; 38:4428-4429. [PMID: 35904542 DOI: 10.1093/bioinformatics/btac534] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/26/2022] [Accepted: 07/27/2022] [Indexed: 12/24/2022] Open
Abstract
MOTIVATION MIB2 (metal ion-binding) attempts to overcome the limitation of structure-based prediction approaches, with many proteins lacking a solved structure. MIB2 also offers more accurate prediction performance and more metal ion types. RESULTS MIB2 utilizes both the (PS)2 method and the AlphaFold Protein Structure Database to acquire predicted structures to perform metal ion docking and predict binding residues. MIB2 offers marked improvements over MIB by collecting more MIB residue templates and using the metal ion type-specific scoring function. It offers a total of 18 types of metal ions for binding site predictions. AVAILABILITY AND IMPLEMENTATION Freely available on the web at http://bioinfo.cmu.edu.tw/MIB2/. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Chih-Hao Lu
- The Ph.D. Program of Biotechnology and Biomedical industry, China Medical University, Taichung 404333, Taiwan.,Institute of Bioinformatics and Systems Biology, National Yang Ming Chiao Tung University, Hsinchu 300193, Taiwan
| | - Chih-Chieh Chen
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 804201, Taiwan
| | - Chin-Sheng Yu
- Department of Information Engineering and Computer Science, Feng Chia University, Taichung 407102, Taiwan
| | - Yen-Yi Liu
- Department of Public Health, China Medical University, Taichung 406040, Taiwan
| | - Jia-Jun Liu
- The Ph.D. Program of Biotechnology and Biomedical industry, China Medical University, Taichung 404333, Taiwan
| | - Sung-Tai Wei
- Department of Neurosurgery, China Medical University Hospital, Taichung 404332, Taiwan
| | - Yu-Feng Lin
- Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung 413305, Taiwan
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7
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Chow V, Nong G, St John FJ, Sawhney N, Rice JD, Preston JF. Bacterial xylan utilization regulons: Systems for coupling depolymerization of methylglucuronoxylans with assimilation and metabolism. J Ind Microbiol Biotechnol 2021; 49:6420245. [PMID: 34734267 DOI: 10.1093/jimb/kuab080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 10/25/2021] [Indexed: 11/14/2022]
Abstract
Bioconversion of lignocellulosic resources to fuels and chemicals offers an economically promising path to renewable energy. Technological challenges to achieving bioconversion include the development of cost-effective processes that render the cellulose and hemicellulose components of these resources to fermentable hexoses and pentoses. Natural bioprocessing of the hemicellulose fraction of lignocellulosic biomass requires depolymerization of methylglucuronoxylans. This depends upon the secretion of endoxylanases that release xylooligosaccharides and aldouronates. Physiological, biochemical and genetic studies with selected bacteria support a process in which a cell-anchored multimodular GH10 endoxylanase catalyzes the release of the hydrolysis products, aldotetrauronate, xylotriose, and xylobiose that are directly assimilated and metabolized. Gene clusters encoding intracellular enzymes, including α-glucuronidase, endo-xylanase, β-xylosidase, ABC transporter proteins, and transcriptional regulators are coordinately responsive to substrate induction or repression. The rapid rates of glucuronoxylan utilization and microbial growth, along with the absence of detectable products of depolymerization in the medium, indicate that assimilation and depolymerization are coupled processes. Genomic comparisons provide evidence that such systems occur in xylanolytic species in several genera, including Clostridium, Geobacillus, Paenibacillus, and Thermotoga. These systems offer promise, either in their native configurations or through gene transfer to other organisms, to develop biocatalysts for efficient production of fuels and chemicals from the hemicellulose fractions of lignocellulosic resources.
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Affiliation(s)
- Virgina Chow
- Department of Microbiology and Cell Science, University of Florida, Gainesville, USA
| | - Guang Nong
- Department of Microbiology and Cell Science, University of Florida, Gainesville, USA
| | - Franz J St John
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, Madison, USA
| | - Neha Sawhney
- Department of Microbiology and Cell Science, University of Florida, Gainesville, USA
| | - John D Rice
- Department of Microbiology and Cell Science, University of Florida, Gainesville, USA
| | - James F Preston
- Department of Microbiology and Cell Science, University of Florida, Gainesville, USA
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8
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Krska D, Mazurkewich S, Brown HA, Theibich Y, Poulsen JCN, Morris AL, Koropatkin NM, Lo Leggio L, Larsbrink J. Structural and Functional Analysis of a Multimodular Hyperthermostable Xylanase-Glucuronoyl Esterase from Caldicellulosiruptor kristjansonii. Biochemistry 2021; 60:2206-2220. [PMID: 34180241 PMCID: PMC8280721 DOI: 10.1021/acs.biochem.1c00305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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The hyperthermophilic bacterium Caldicellulosiruptor kristjansonii encodes an unusual enzyme, CkXyn10C-GE15A, which
incorporates two catalytic domains, a xylanase and a glucuronoyl esterase,
and five carbohydrate-binding modules (CBMs) from families 9 and 22.
The xylanase and glucuronoyl esterase catalytic domains were recently
biochemically characterized, as was the ability of the individual
CBMs to bind insoluble polysaccharides. Here, we further probed the
abilities of the different CBMs from CkXyn10C-GE15A
to bind to soluble poly- and oligosaccharides using affinity gel electrophoresis,
isothermal titration calorimetry, and differential scanning fluorimetry.
The results revealed additional binding properties of the proteins
compared to the former studies on insoluble polysaccharides. Collectively,
the results show that all five CBMs have their own distinct binding
preferences and appear to complement each other and the catalytic
domains in targeting complex cell wall polysaccharides. Additionally,
through renewed efforts, we have achieved partial structural characterization
of this complex multidomain protein. We have determined the structures
of the third CBM9 domain (CBM9.3) and the glucuronoyl esterase (GE15A)
by X-ray crystallography. CBM9.3 is the second CBM9 structure determined
to date and was shown to bind oligosaccharide ligands at the same
site but in a different binding mode compared to that of the previously
determined CBM9 structure from Thermotoga maritima. GE15A represents a unique intermediate between reported fungal
and bacterial glucuronoyl esterase structures as it lacks two inserted
loop regions typical of bacterial enzymes and a third loop has an
atypical structure. We also report small-angle X-ray scattering measurements
of the N-terminal CBM22.1–CBM22.2–Xyn10C construct,
indicating a compact arrangement at room temperature.
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Affiliation(s)
- Daniel Krska
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Scott Mazurkewich
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.,Wallenberg Wood Science Center, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Haley A Brown
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Yusuf Theibich
- Department of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | | | - Adeline L Morris
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Leila Lo Leggio
- Department of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Johan Larsbrink
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.,Wallenberg Wood Science Center, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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9
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Krska D, Larsbrink J. Investigation of a thermostable multi-domain xylanase-glucuronoyl esterase enzyme from Caldicellulosiruptor kristjanssonii incorporating multiple carbohydrate-binding modules. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:68. [PMID: 32308737 PMCID: PMC7151638 DOI: 10.1186/s13068-020-01709-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/02/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Efficient degradation of lignocellulosic biomass has become a major bottleneck in industrial processes which attempt to use biomass as a carbon source for the production of biofuels and materials. To make the most effective use of the source material, both the hemicellulosic as well as cellulosic parts of the biomass should be targeted, and as such both hemicellulases and cellulases are important enzymes in biorefinery processes. Using thermostable versions of these enzymes can also prove beneficial in biomass degradation, as they can be expected to act faster than mesophilic enzymes and the process can also be improved by lower viscosities at higher temperatures, as well as prevent the introduction of microbial contamination. RESULTS This study presents the investigation of the thermostable, dual-function xylanase-glucuronoyl esterase enzyme CkXyn10C-GE15A from the hyperthermophilic bacterium Caldicellulosiruptor kristjanssonii. Biochemical characterization of the enzyme was performed, including assays for establishing the melting points for the different protein domains, activity assays for the two catalytic domains, as well as binding assays for the multiple carbohydrate-binding domains present in CkXyn10C-GE15A. Although the enzyme domains are naturally linked together, when added separately to biomass, the expected boosting of the xylanase action was not seen. This lack of intramolecular synergy might suggest, together with previous data, that increased xylose release is not the main beneficial trait given by glucuronoyl esterases. CONCLUSIONS Due to its thermostability, CkXyn10C-GE15A is a promising candidate for industrial processes, with both catalytic domains exhibiting melting temperatures over 70 °C. Of particular interest is the glucuronoyl esterase domain, as it represents the first studied thermostable enzyme displaying this activity.
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Affiliation(s)
- Daniel Krska
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Johan Larsbrink
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
- Wallenberg Wood Science Center, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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10
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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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11
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Wang R, Xu D. Molecular dynamics investigations of oligosaccharides recognized by family 16 and 22 carbohydrate binding modules. Phys Chem Chem Phys 2019; 21:21485-21496. [PMID: 31535114 DOI: 10.1039/c9cp04673a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
As a non-catalytic domain, carbohydrate binding modules (CBMs) are often considered to play some key roles in the degradation and recognition of polysaccharides catalyzed by cellulases. In this work, we investigated the recognition dynamics of cello- or xylo-saccharides by two typical CBMs (CBM16-1 and CBM22-2), which are grouped into Type B CBMs. By combining extensive molecular dynamics, principle component analysis, and binding free energy calculations, we constructed several complex models of the two CBMs in both complex cello- and xylo-oligosaccharides. The corresponding substrate recognition affinity and critical residues having significant contributions were systematically investigated. The residues containing aromatic side chain groups were shown to contribute significantly to substrate binding. The calculated binding free energies were in fairly good agreement with the experimental measurements with the absolute mean error of 0.69 kcal mol-1. The overall electrostatic interactions were shown to have negative effects on substrate recognition. Further metadynamics simulations revealed the substrate dissociation process.
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Affiliation(s)
- Ruihan Wang
- MOE Key Laboratory of Green Chemistry and Technology, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P. R. China.
| | - Dingguo Xu
- MOE Key Laboratory of Green Chemistry and Technology, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P. R. China. and Research Center for Materials Genome Engineering, Sichuan University, Chengdu, Sichuan 610065, P. R. China
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12
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Jia X, Han Y. The extracellular endo-β-1,4-xylanase with multidomain from the extreme thermophile Caldicellulosiruptor lactoaceticus is specific for insoluble xylan degradation. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:143. [PMID: 31198440 PMCID: PMC6556019 DOI: 10.1186/s13068-019-1480-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 05/29/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND The extremely thermophilic bacterium Caldicellulosiruptor lactoaceticus can degrade and metabolize untreated lignocellulosic biomass containing xylan. The mechanism of the bacterium for degradation of insoluble xylan in untreated biomass has not been revealed. RESULTS In the present study, the only annotated extracellular endo-β-1,4-xylanase (Xyn10B) with multidomain structures in C. lactoaceticus genome was biochemically characterized. Xyn10B contains three N-terminal consecutive family 22 carbohydrate-binding modules (CBMs), one GH10 catalytic domain (CD), two family 9 CBMs and two S-layer homology (SLH) modules in the C-terminal. CBM22a shares 27.1% and 27.2% sequence homology with CBM22b and CBM22c, respectively. The sequence homology between two CBM9 s and two SLHs is 26.8% and 25.6%, respectively. To elucidate the effect of multiple domains on the enzymatic properties of Xyn10B, the truncated variants of which (Xyn10B-TM1: CBM22a-CBM22b-CBM22c-CD10; Xyn10B-TM2: CBM22c-CD10; Xyn10B-TM3: CBM22c-CD10-CBM9a; and Xyn10B-TM4: CD10-CBM9a) were separately reconstructed, recombinantly expressed and biochemically characterized. Enzymatic properties studies showed that the optimal temperature for all four Xyn10B truncations was 65 °C. Compared to Xyn10B-TM3 and Xyn10B-TM4, Xyn10B-TM1 and Xyn10B-TM2 had higher hydrolytic activity, thermostability and affinity on insoluble substrates. It is noteworthy that Xyn10B-TM1 and Xyn10B-TM2 have higher enzymatic activity on insoluble xylan than the soluble counterparts, whereas Xyn10B-TM3 and Xyn10B-TM4 showed opposite characteristics. The kinetic parameters analysis of Xyn10B-TM1 on xylan showed V max was 5740, 1300, 1033, and 3925 U/μmol on insoluble oat spelt xylan (OSX), soluble beechwood xylan (BWX), soluble sugar cane xylan (SCX), and soluble corncob xylan (CCX), respectively. The results indicated that CBM22s especially CBM22c promoted the hydrolytic activity, thermostability and affinity on insoluble substrates of the Xyn10B truncations. The functions of CBM22, CBM9, CD and SLH are different, while contribute synergetically to the thermostability, protein structure integrity, substrate binding, and high hydrolytic activity on insoluble xylan of untreated lignocellulosic biomass. The domains of CBM22, CBM9, CD and SLH have different characteristics, which synergistically promote the thermostability, protein structure integrity, affinity on insoluble substrates and enzymatic activity properties of Xyn10B. CONCLUSIONS The extracellular endo-β-1,4-xylanase with multidomain structures of CBM, CD and SLH promote the biodegradation of insoluble xylan in untreated lignocellulosic biomass by thermophilic C. lactoaceticus.
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Affiliation(s)
- Xiaojing Jia
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology & Business University, Beijing, 100048 China
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yejun Han
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190 China
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13
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Discovery of a Thermostable GH10 Xylanase with Broad Substrate Specificity from the Arctic Mid-Ocean Ridge Vent System. Appl Environ Microbiol 2019; 85:AEM.02970-18. [PMID: 30635385 DOI: 10.1128/aem.02970-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 01/03/2019] [Indexed: 11/20/2022] Open
Abstract
A two-domain GH10 xylanase-encoding gene (amor_gh10a) was discovered from a metagenomic data set, generated after in situ incubation of a lignocellulosic substrate in hot sediments on the sea floor of the Arctic Mid-Ocean Ridge (AMOR). AMOR_GH10A comprises a signal peptide, a carbohydrate-binding module belonging to a previously uncharacterized family, and a catalytic glycosyl hydrolase (GH10) domain. The enzyme shares the highest sequence identity (42%) with a hypothetical protein from a Verrucomicrobia bacterium, and its GH10 domain shares low identity (24 to 28%) with functionally characterized xylanases. Purified AMOR_GH10A showed thermophilic and halophilic properties and was active toward various xylans. Uniquely, the enzyme showed high activity toward amorphous cellulose, glucomannan, and xyloglucan and was more active toward cellopentaose than toward xylopentaose. Binding assays showed that the N-terminal domain of this broad-specificity GH10 binds strongly to amorphous cellulose, as well as to microcrystalline cellulose, birchwood glucuronoxylan, barley β-glucan, and konjac glucomannan, confirming its classification as a novel CBM (CBM85).IMPORTANCE Hot springs at the sea bottom harbor unique biodiversity and are a promising source of enzymes with interesting properties. We describe the functional characterization of a thermophilic and halophilic multidomain xylanase originating from the Arctic Mid-Ocean Ridge vent system, belonging to the well-studied family 10 of glycosyl hydrolases (GH10). This xylanase, AMOR_GH10A, has a surprisingly wide substrate range and is more active toward cellopentaose than toward xylopentaose. This substrate promiscuity is unique for the GH10 family and could prove useful in industrial applications. Emphasizing the versatility of AMOR_GH10A, its N-terminal domain binds to both xylans and glycans, while not showing significant sequence similarities to any known carbohydrate-binding module (CBM) in the CAZy database. Thus, this N-terminal domain lays the foundation for the new CBM85 family.
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14
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Li P, Zhang C, Xu D. Molecular dynamics investigations of cello-oligosaccharide recognition by Cel9G-CBM3c from Clostridium cellulovorans. Phys Chem Chem Phys 2018; 20:5235-5245. [PMID: 29399685 DOI: 10.1039/c7cp07175b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The processive mechanism of cellulases against cellulose represents one of the key mechanisms in the conversion of biomass. A reliable model of substrate binding in a multidomain cellulase is a prerequisite for fully understanding this mechanism. In this study, the specificity of the recognition of the polysaccharide by the multidomain endoglucanase Cel9G from Clostridium cellulovorans was investigated by molecular dynamics simulations. Aromatic ring-containing residues were found to be critical for stabilizing the substrate. The calculated subtotal contributions of polar residues close to the active site, e.g., D58, E244, R315 and D420, also have some critical functions in substrate binding. Unlike other members of the carbohydrate-binding module family, CBM3c alone is shown not to bind cellulose very well, which is also consistent with experimental conclusions.
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Affiliation(s)
- Penghui Li
- MOE Key Laboratory of Green Chemistry, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, People's Republic of China.
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15
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You X, Qin Z, Li YX, Yan QJ, Li B, Jiang ZQ. Structural and biochemical insights into the substrate-binding mechanism of a novel glycoside hydrolase family 134 β-mannanase. Biochim Biophys Acta Gen Subj 2018; 1862:1376-1388. [DOI: 10.1016/j.bbagen.2018.03.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 03/08/2018] [Accepted: 03/10/2018] [Indexed: 12/11/2022]
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16
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Bobbili KB, Pohlentz G, Narahari A, Sharma K, Surolia A, Mormann M, Swamy MJ. Coccinia indica agglutinin, a 17 kDa PP2 like phloem lectin: Affinity purification, primary structure and formation of self-assembled filaments. Int J Biol Macromol 2018; 108:1227-1236. [DOI: 10.1016/j.ijbiomac.2017.11.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/04/2017] [Accepted: 11/06/2017] [Indexed: 12/23/2022]
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17
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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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18
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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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19
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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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20
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Sainz-Polo MA, González B, Menéndez M, Pastor FIJ, Sanz-Aparicio J. Exploring Multimodularity in Plant Cell Wall Deconstruction: STRUCTURAL AND FUNCTIONAL ANALYSIS OF Xyn10C CONTAINING THE CBM22-1-CBM22-2 TANDEM. J Biol Chem 2015; 290:17116-30. [PMID: 26001782 DOI: 10.1074/jbc.m115.659300] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Indexed: 11/06/2022] Open
Abstract
Elucidating the molecular mechanisms regulating multimodularity is a challenging task. Paenibacillus barcinonensis Xyn10C is a 120-kDa modular enzyme that presents the CBM22/GH10/CBM9 architecture found in a subset of large xylanases. We report here the three-dimensional structure of the Xyn10C N-terminal region, containing the xylan-binding CBM22-1-CBM22-2 tandem (Xyn10C-XBD), which represents the first solved crystal structure of two contiguous CBM22 modules. Xyn10C-XBD is folded into two separate CBM22 modules linked by a flexible segment that endows the tandem with extraordinary plasticity. Each isolated domain has been expressed and crystallized, and their binding abilities have been investigated. Both domains contain the R(W/Y)YYE motif required for xylan binding. However, crystallographic analysis of CBM22-2 complexes shows Trp-308 as an additional binding determinant. The long loop containing Trp-308 creates a platform that possibly contributes to the recognition of precise decorations at subsite S2. CBM22-2 may thus define a subset of xylan-binding CBM22 modules directed to particular regions of the polysaccharide. Affinity electrophoresis reveals that Xyn10C-XBD binds arabinoxylans more tightly, which is more apparent when CBM22-2 is tested against highly substituted xylan. The crystal structure of the catalytic domain, also reported, shows the capacity of the active site to accommodate xylan substitutions at almost all subsites. The structural differences found at both Xyn10C-XBD domains are consistent with the isothermal titration calorimetry experiments showing two sites with different affinities in the tandem. On the basis of the distinct characteristics of CBM22, a delivery strategy of Xyn10C mediated by Xyn10C-XBD is proposed.
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Affiliation(s)
| | - Beatriz González
- From the Departamentos de Cristalografía y Biología Estructural y
| | - Margarita Menéndez
- Química Física Biólogica, Instituto de Química-Física Rocasolano, Consejo Superior de Investigaciones Científicas, Serrano 119, 28006-Madrid and
| | - F I Javier Pastor
- the Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain
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21
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Zhang X, Rogowski A, Zhao L, Hahn MG, Avci U, Knox JP, Gilbert HJ. Understanding how the complex molecular architecture of mannan-degrading hydrolases contributes to plant cell wall degradation. J Biol Chem 2014; 289:2002-12. [PMID: 24297170 PMCID: PMC3900950 DOI: 10.1074/jbc.m113.527770] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/25/2013] [Indexed: 12/16/2022] Open
Abstract
Microbial degradation of plant cell walls is a central component of the carbon cycle and is of increasing importance in environmentally significant industries. Plant cell wall-degrading enzymes have a complex molecular architecture consisting of catalytic modules and, frequently, multiple non-catalytic carbohydrate binding modules (CBMs). It is currently unclear whether the specificities of the CBMs or the topology of the catalytic modules are the primary drivers for the specificity of these enzymes against plant cell walls. Here, we have evaluated the relationship between CBM specificity and their capacity to enhance the activity of GH5 and GH26 mannanases and CE2 esterases against intact plant cell walls. The data show that cellulose and mannan binding CBMs have the greatest impact on the removal of mannan from tobacco and Physcomitrella cell walls, respectively. Although the action of the GH5 mannanase was independent of the context of mannan in tobacco cell walls, a significant proportion of the polysaccharide was inaccessible to the GH26 enzyme. The recalcitrant mannan, however, was fully accessible to the GH26 mannanase appended to a cellulose binding CBM. Although CE2 esterases display similar specificities against acetylated substrates in vitro, only CjCE2C was active against acetylated mannan in Physcomitrella. Appending a mannan binding CBM27 to CjCE2C potentiated its activity against Physcomitrella walls, whereas a xylan binding CBM reduced the capacity of esterases to deacetylate xylan in tobacco walls. This work provides insight into the biological significance for the complex array of hydrolytic enzymes expressed by plant cell wall-degrading microorganisms.
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Affiliation(s)
- Xiaoyang Zhang
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle-upon-Tyne, NE 4HH, United Kingdom
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - Artur Rogowski
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle-upon-Tyne, NE 4HH, United Kingdom
| | - Lei Zhao
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - Michael G. Hahn
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - Utku Avci
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - J. Paul Knox
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Harry J. Gilbert
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle-upon-Tyne, NE 4HH, United Kingdom
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
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22
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Gilbert HJ, Knox JP, Boraston AB. Advances in understanding the molecular basis of plant cell wall polysaccharide recognition by carbohydrate-binding modules. Curr Opin Struct Biol 2013; 23:669-77. [DOI: 10.1016/j.sbi.2013.05.005] [Citation(s) in RCA: 236] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 05/03/2013] [Accepted: 05/09/2013] [Indexed: 11/25/2022]
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23
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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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24
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Novel structural features of xylanase A1 from Paenibacillus sp. JDR-2. J Struct Biol 2012; 180:303-11. [PMID: 23000703 DOI: 10.1016/j.jsb.2012.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 08/28/2012] [Accepted: 09/03/2012] [Indexed: 11/24/2022]
Abstract
The Gram-positive bacterium Paenibacillus sp. JDR-2 (PbJDR2) has been shown to have novel properties in the utilization of the abundant but chemically complex hemicellulosic sugar glucuronoxylan. Xylanase A1 of PbJDR2 (PbXynA1) has been implicated in an efficient process in which extracellular depolymerization of this polysaccharide is coupled to assimilation and intracellular metabolism. PbXynA1is a 154kDa cell wall anchored multimodular glycosyl hydrolase family 10 (GH10) xylanase. In this work, the 38kDa catalytic module of PbXynA1 has been structurally characterized revealing several new features not previously observed in structures of GH10 xylanases. These features are thought to facilitate hydrolysis of highly substituted, chemically complex xylans that may be the form found in close proximity to the cell wall of PbJDR2, an organism shown to have a preference for growth on polymeric glucuronoxylan.
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25
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Dissecting structure–function–stability relationships of a thermostable GH5-CBM3 cellulase from Bacillus subtilis 168. Biochem J 2011; 441:95-104. [DOI: 10.1042/bj20110869] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cellulases participate in a number of biological events, such as plant cell wall remodelling, nematode parasitism and microbial carbon uptake. Their ability to depolymerize crystalline cellulose is of great biotechnological interest for environmentally compatible production of fuels from lignocellulosic biomass. However, industrial use of cellulases is somewhat limited by both their low catalytic efficiency and stability. In the present study, we conducted a detailed functional and structural characterization of the thermostable BsCel5A (Bacillus subtilis cellulase 5A), which consists of a GH5 (glycoside hydrolase 5) catalytic domain fused to a CBM3 (family 3 carbohydrate-binding module). NMR structural analysis revealed that the Bacillus CBM3 represents a new subfamily, which lacks the classical calcium-binding motif, and variations in NMR frequencies in the presence of cellopentaose showed the importance of polar residues in the carbohydrate interaction. Together with the catalytic domain, the CBM3 forms a large planar surface for cellulose recognition, which conducts the substrate in a proper conformation to the active site and increases enzymatic efficiency. Notably, the manganese ion was demonstrated to have a hyper-stabilizing effect on BsCel5A, and by using deletion constructs and X-ray crystallography we determined that this effect maps to a negatively charged motif located at the opposite face of the catalytic site.
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26
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Valdez HA, Peralta DA, Wayllace NZ, Grisolía MJ, Gomez-Casati DF, Busi MV. Preferential binding of SBD from Arabidopsis thaliana SSIII to polysaccharides: Study of amino acid residues involved. STARCH-STARKE 2011. [DOI: 10.1002/star.201000111] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Hwang H, Vreven T, Pierce BG, Hung JH, Weng Z. Performance of ZDOCK and ZRANK in CAPRI rounds 13-19. Proteins 2010; 78:3104-10. [PMID: 20936681 PMCID: PMC3936321 DOI: 10.1002/prot.22764] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We report the performance of the ZDOCK and ZRANK algorithms in CAPRI rounds 13-19 and introduce a novel measure atom contact frequency (ACF). To compute ACF, we identify the residues that most often make contact with the binding partner in the complete set of ZDOCK predictions for each target. We used ACF to predict the interface of the proteins, which, in combination with the biological data available in the literature, is a valuable addition to our docking pipeline. Furthermore, we incorporated a straightforward and efficient clustering algorithm with two purposes: (1) to determine clusters of similar docking poses (corresponding to energy funnels) and (2) to remove redundancies from the final set of predictions. With these new developments, we achieved at least one acceptable prediction for targets 29 and 36, at least one medium-quality prediction for targets 41 and 42, and at least one high-quality prediction for targets 37 and 40; thus, we succeeded for six out of a total of 12 targets.
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Affiliation(s)
- Howook Hwang
- Bioinformatics Program, Boston University, Boston, Massachusetts 02215, USA
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28
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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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29
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Voronina AS, Pshennikova ES. Substrate-binding properties of the family 54 module of Clostridium thermocellum Lic16A laminarinase. Mol Biol 2010; 44:591-600. [PMID: 20873216 DOI: 10.1134/s002689331004014x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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30
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Schouppe D, Rougé P, Lasanajak Y, Barre A, Smith DF, Proost P, Van Damme EJM. Mutational analysis of the carbohydrate binding activity of the tobacco lectin. Glycoconj J 2010; 27:613-23. [PMID: 20721621 PMCID: PMC3005260 DOI: 10.1007/s10719-010-9305-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 07/20/2010] [Accepted: 07/23/2010] [Indexed: 10/19/2022]
Abstract
At present the three-dimensional structure of the tobacco lectin, further referred to as Nictaba, and its carbohydrate-binding site are unresolved. In this paper, we propose a three-dimensional model for the Nictaba domain based on the homology between Nictaba and the carbohydrate-binding module 22 of Clostridium thermocellum Xyn10B. The suggested model nicely fits with results from circular dichroism experiments, indicating that Nictaba consists mainly of β-sheet. In addition, the previously identified nuclear localization signal is located at the top of the protein as a part of a protruding loop. Judging from this model and sequence alignments with closely related proteins, conserved glutamic acid and tryptophan residues in the Nictaba sequence were selected for mutational analysis. The mutant DNA sequences as well as the original Nictaba sequence have been expressed in Pichia pastoris and the recombinant proteins were purified from the culture medium. Subsequently, the recombinant proteins were characterized and their carbohydrate binding properties analyzed with glycan array technology. It was shown that mutation of glutamic acid residues in the C-terminal half of the protein did not alter the carbohydrate-binding activity of the lectin. In contrast, mutation of tryptophan residues in the N-terminal half of the Nictaba domain resulted in a complete loss of carbohydrate binding activity. These results suggest that tryptophan residues play an important role in the carbohydrate binding site of Nictaba.
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Affiliation(s)
- Dieter Schouppe
- Department of Molecular Biotechnology, Laboratory of Biochemistry and Glycobiology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Pierre Rougé
- Surfaces Cellulaires et Signalisation chez les Végétaux, UMR-CNRS 5546, Pôle de Biotechnologie Végétale, Toulouse, France
| | - Yi Lasanajak
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Annick Barre
- Surfaces Cellulaires et Signalisation chez les Végétaux, UMR-CNRS 5546, Pôle de Biotechnologie Végétale, Toulouse, France
| | - David F. Smith
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Paul Proost
- Laboratory of Molecular Immunology, Rega Institute for Medical Research, University of Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium
| | - Els J. M. Van Damme
- Department of Molecular Biotechnology, Laboratory of Biochemistry and Glycobiology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
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31
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Mohamed MNA, Watts HD, Guo J, Catchmark JM, Kubicki JD. MP2, density functional theory, and molecular mechanical calculations of C–H···π and hydrogen bond interactions in a cellulose-binding module–cellulose model system. Carbohydr Res 2010; 345:1741-51. [DOI: 10.1016/j.carres.2010.05.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 05/10/2010] [Accepted: 05/22/2010] [Indexed: 10/19/2022]
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32
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Najmudin S, Pinheiro BA, Prates JAM, Gilbert HJ, Romão MJ, Fontes CMGA. Putting an N-terminal end to the Clostridium thermocellum xylanase Xyn10B story: crystal structure of the CBM22-1-GH10 modules complexed with xylohexaose. J Struct Biol 2010; 172:353-62. [PMID: 20682344 DOI: 10.1016/j.jsb.2010.07.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/26/2010] [Accepted: 07/29/2010] [Indexed: 10/19/2022]
Abstract
In general, plant cell wall degrading enzymes are modular proteins containing catalytic domains linked to one or more non-catalytic carbohydrate-binding modules (CBMs). Xyn10B from Clostridium thermocellum is a typical modular enzyme containing an N-terminal family 22 CBM (CBM22-1), a family 10 glycoside hydrolase catalytic domain (GH10), a second CBM22 (CBM22-2), a dockerin sequence and a C-terminal family 1 carbohydrate esterase (CE1) catalytic domain. The structure of the N-terminal bi-modular CBM22-1-GH10 component of Xyn10B has been determined using a SeMet derivative by SAD to 2.5Å. The data was extended to 2.0Å for the non-SeMet mutant complexed with xylohexaose. CBM22-1-GH10 is a 60kDa protein with an E337A mutation to render the GH10 subunit inactive. Three of the six xylose residues of xylohexaose are shown to be bound in the inactivated GH10 substrate binding cleft, with the other three sugars presumably disordered in the solvent channel. The protein is a dimer in the asymmetric unit with extensive surface contacts between the two GH10 modules and between the CBM22-1 and GH10 modules. Residues from helix H4 of the GH10 module provide the major contacts by fitting into the minor groove of the CBM22-1 module. The orientation of CBM22-1 is such that it would allow the substrate to be loosely bound and subsequently delivered to the active site in a processive manner.
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Affiliation(s)
- Shabir Najmudin
- CIISA - Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
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33
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Beneteau J, Renard D, Marché L, Douville E, Lavenant L, Rahbé Y, Dupont D, Vilaine F, Dinant S. Binding properties of the N-acetylglucosamine and high-mannose N-glycan PP2-A1 phloem lectin in Arabidopsis. PLANT PHYSIOLOGY 2010; 153:1345-61. [PMID: 20442276 PMCID: PMC2899916 DOI: 10.1104/pp.110.153882] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Accepted: 04/28/2010] [Indexed: 05/18/2023]
Abstract
Phloem Protein2 (PP2) is a component of the phloem protein bodies found in sieve elements. We describe here the lectin properties of the Arabidopsis (Arabidopsis thaliana) PP2-A1. Using a recombinant protein produced in Escherichia coli, we demonstrated binding to N-acetylglucosamine oligomers. Glycan array screening showed that PP2-A1 also bound to high-mannose N-glycans and 9-acyl-N-acetylneuraminic sialic acid. Fluorescence spectroscopy-based titration experiments revealed that PP2-A1 had two classes of binding site for N,N',N''-triacetylchitotriose, a low-affinity site and a high-affinity site, promoting the formation of protein dimers. A search for structural similarities revealed that PP2-A1 aligned with the Cbm4 and Cbm22-2 carbohydrate-binding modules, leading to the prediction of a beta-strand structure for its conserved domain. We investigated whether PP2-A1 interacted with phloem sap glycoproteins by first characterizing abundant Arabidopsis phloem sap proteins by liquid chromatography-tandem mass spectrometry. Then we demonstrated that PP2-A1 bound to several phloem sap proteins and that this binding was not completely abolished by glycosidase treatment. As many plant lectins have insecticidal activity, we also assessed the effect of PP2-A1 on weight gain and survival in aphids. Unlike other mannose-binding lectins, when added to an artificial diet, recombinant PP2-A1 had no insecticidal properties against Acyrthosiphon pisum and Myzus persicae. However, at mid-range concentrations, the protein affected weight gain in insect nymphs. These results indicate the presence in PP2-A1 of several carbohydrate-binding sites, with potentially different functions in the trafficking of endogenous proteins or in interactions with phloem-feeding insects.
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34
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Schallus T, Fehér K, Sternberg U, Rybin V, Muhle-Goll C. Analysis of the specific interactions between the lectin domain of malectin and diglucosides. Glycobiology 2010; 20:1010-20. [DOI: 10.1093/glycob/cwq059] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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35
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van Ameijde J, Poot AJ, van Wandelen LTM, Wammes AEM, Ruijtenbeek R, Rijkers DTS, Liskamp RMJ. Preparation of novel alkylated arginine derivatives suitable for click-cycloaddition chemistry and their incorporation into pseudosubstrate- and bisubstrate-based kinase inhibitors. Org Biomol Chem 2010; 8:1629-39. [PMID: 20237675 DOI: 10.1039/b922928k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Efficient strategies for the introduction of arginine residues featuring acetylene or azide moieties in their side chains are described. The substituents are introduced in a way that maintains the basicity of the guanidine moiety. The methodology can be used e.g. for non-invasive labeling of arginine-containing peptides. Its applicability is demonstrated by the introduction of 'click' handles into a Protein Kinase C (PKC) pseudosubstrate peptide, and the subsequent preparation and evaluation of a novel bisubstrate-based inhibitor based on such a peptide.
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Affiliation(s)
- Jeroen van Ameijde
- Medicinal Chemistry and Chemical Biology, Faculty of Science, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands
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36
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Christiansen C, Abou Hachem M, Janecek S, Viksø-Nielsen A, Blennow A, Svensson B. The carbohydrate-binding module family 20--diversity, structure, and function. FEBS J 2009; 276:5006-29. [PMID: 19682075 DOI: 10.1111/j.1742-4658.2009.07221.x] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Starch-active enzymes often possess starch-binding domains (SBDs) mediating attachment to starch granules and other high molecular weight substrates. SBDs are divided into nine carbohydrate-binding module (CBM) families, and CBM20 is the earliest-assigned and best characterized family. High diversity characterizes CBM20s, which occur in starch-active glycoside hydrolase families 13, 14, 15, and 77, and enzymes involved in starch or glycogen metabolism, exemplified by the starch-phosphorylating enzyme glucan, water dikinase 3 from Arabidopsis thaliana and the mammalian glycogen phosphatases, laforins. The clear evolutionary relatedness of CBM20s to CBM21s, CBM48s and CBM53s suggests a common clan hosting most of the known SBDs. This review surveys the diversity within the CBM20 family, and makes an evolutionary comparison with CBM21s, CBM48s and CBM53s, discussing intrafamily and interfamily relationships. Data on binding to and enzymatic activity towards soluble ligands and starch granules are summarized for wild-type, mutant and chimeric fusion proteins involving CBM20s. Noticeably, whereas CBM20s in amylolytic enzymes confer moderate binding affinities, with dissociation constants in the low micromolar range for the starch mimic beta-cyclodextrin, recent findings indicate that CBM20s in regulatory enzymes have weaker, low millimolar affinities, presumably facilitating dynamic regulation. Structures of CBM20s, including the first example of a full-length glucoamylase featuring both the catalytic domain and the SBD, are summarized, and distinct architectural and functional features of the two SBDs and roles of pivotal amino acids in binding are described. Finally, some applications of SBDs as affinity or immobilization tags and, recently, in biofuel and in planta bioengineering are presented.
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Affiliation(s)
- Camilla Christiansen
- VKR Research Centre Pro-Active Plants, Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark
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37
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Cicortas Gunnarsson L, Nordberg Karlsson E, Andersson M, Holst O, Ohlin M. Molecular engineering of a thermostable carbohydrate-binding module. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420500518516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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38
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Carbohydrate-binding properties of a separately folding protein module from β-1,3-glucanase Lic16A of Clostridium thermocellum. Microbiology (Reading) 2009; 155:2442-2449. [DOI: 10.1099/mic.0.026930-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The multi-modular non-cellulosomal endo-1,3(4)-β-glucanase Lic16A from Clostridium thermocellum contains a so-called X module (denoted as CBMX) near the N terminus of the catalytic module (191–426 aa). Melting of X-module-containing recombinant proteins revealed an independent folding of the module. CBMX was isolated and studied as a separate fragment. It was shown to bind to various insoluble polysaccharides, including xylan, pustulan, chitin, chitosan, yeast cell wall glucan, Avicel and bacterial crystalline cellulose. CBMX thus contains a hitherto unknown carbohydrate-binding module (CBM54). It did not bind soluble polysaccharides on which Lic16A is highly active. Ca2+ ions had effects on the binding, e.g. stimulated complex formation with chitosan, which was observed only in the presence of Ca2+. The highest affinity to CBMX was shown for xylan (binding constant K=3.1×104 M−1), yeast cell wall glucan (K=1.4×105 M−1) and chitin (K=3.3.105 M−1 in the presence of Ca2+). Lic16A deletion derivatives lacking CBMX had lower affinity to lichenan and laminarin and a slight decrease in optimum temperature and thermostability. However, the specific activity was not significantly affected.
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39
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Caines ME, Zhu H, Vuckovic M, Willis LM, Withers SG, Wakarchuk WW, Strynadka NC. The Structural Basis for T-antigen Hydrolysis by Streptococcus pneumoniae. J Biol Chem 2008; 283:31279-83. [DOI: 10.1074/jbc.c800150200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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40
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Najmudin S, Pinheiro BA, Romão MJ, Prates JAM, Fontes CMGA. Purification, crystallization and crystallographic analysis of Clostridium thermocellum endo-1,4-beta-D-xylanase 10B in complex with xylohexaose. Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:715-8. [PMID: 18678939 PMCID: PMC2494957 DOI: 10.1107/s1744309108019696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 06/27/2008] [Indexed: 11/10/2022]
Abstract
The cellulosome of Clostridium thermocellum is a highly organized multi-enzyme complex of cellulases and hemicellulases involved in the hydrolysis of plant cell-wall polysaccharides. The bifunctional multi-modular xylanase Xyn10B is one of the hemicellulase components of the C. thermocellum cellulosome. The enzyme contains an internal glycoside hydrolase family 10 catalytic domain (GH10) and a C-terminal family 1 carbohydrate esterase domain (CE1). The N-terminal moiety of Xyn10B (residues 32-551), comprising a carbohydrate-binding module (CBM22-1) and the GH10 E337A mutant, was crystallized in complex with xylohexaose. The crystals belong to the trigonal space group P3(2)21 and contain a dimer in the asymmetric unit. The crystals diffracted to beyond 2.0 A resolution.
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Affiliation(s)
- Shabir Najmudin
- REQUIMTE, Departamento de Química, FCT-UNL, 2829-516 Caparica, Portugal
| | - Benedita A. Pinheiro
- CIISA – Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Maria J. Romão
- REQUIMTE, Departamento de Química, FCT-UNL, 2829-516 Caparica, Portugal
| | - José A. M. Prates
- CIISA – Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Carlos M. G. A. Fontes
- CIISA – Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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41
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Junkes C, Wessolowski A, Farnaud S, Evans RW, Good L, Bienert M, Dathe M. The interaction of arginine- and tryptophan-rich cyclic hexapeptides with Escherichia coli membranes. J Pept Sci 2008; 14:535-43. [PMID: 17985396 DOI: 10.1002/psc.940] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cyclization of R- and W-rich hexapeptides has been found to enhance specifically the antimicrobial activity against Gram-negative Escherichia coli. To gain insight into the role of the bacterial outer membrane in mediating selectivity, we assayed the activity of cyclic hexapeptides derived from the parent sequence c-(RRWWRF) against several E. coli strains and Bacillus subtilis, L-form bacteria, and E. coli lipopolysaccharide (LPS) mutant strains, and we also investigated the peptide-induced permeabilization of the outer and inner membrane of E. coli. Wall-deficient L-form bacteria were distinctly less susceptible than the wild type strain. The patterns of peptide-induced permeabilization of the outer and inner E. coli membranes correlated well with the antimicrobial activity, confirming that membrane permeabilization is a detrimental effect of the peptides upon bacteria. Truncation of LPS had no influence on the activity of the cyclic parent peptide, but the highly active c-(RRWFWR), with three adjacent aromatic residues, required the complete LPS for maximal activity. Furthermore, differences in the activity of the parent peptide and its all-D sequence indicated stereospecific interactions with the LPS mutant strains. We suggest that, depending on the primary sequence of the peptides, either hydrophobic interactions with the fatty acid chains of lipid A, or electrostatic interactions disturbing the polar core region and interference with saccharide-saccharide interactions prevail in the barrier-disturbing effect upon the outer membrane and thereby provide peptide accessibility to the inner membrane. The results underline the importance of tryptophan and arginine residues and their relative location for a high antimicrobial effect, and the activity-modulating function of the outer membrane of E. coli. In addition to membrane permeabilization, the data provided evidence for the involvement of other mechanisms in growth inhibition and killing of bacteria.
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Affiliation(s)
- Christof Junkes
- Leibniz Institute of Molecular Pharmacology, Robert-Rössle-Str. 10, 13125 Berlin, Germany
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42
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Viegas A, Brás NF, Cerqueira NMFSA, Fernandes PA, Prates JAM, Fontes CMGA, Bruix M, Romão MJ, Carvalho AL, Ramos MJ, Macedo AL, Cabrita EJ. Molecular determinants of ligand specificity in family 11 carbohydrate binding modules - an NMR, X-ray crystallography and computational chemistry approach. FEBS J 2008; 275:2524-35. [DOI: 10.1111/j.1742-4658.2008.06401.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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43
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Cicortas Gunnarsson L, Montanier C, Tunnicliffe R, Williamson M, Gilbert H, Nordberg Karlsson E, Ohlin M. Novel xylan-binding properties of an engineered family 4 carbohydrate-binding module. Biochem J 2007; 406:209-14. [PMID: 17506724 PMCID: PMC1948960 DOI: 10.1042/bj20070128] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Molecular engineering of ligand-binding proteins is commonly used for identification of variants that display novel specificities. Using this approach to introduce novel specificities into CBMs (carbohydrate-binding modules) has not been extensively explored. Here, we report the engineering of a CBM, CBM4-2 from the Rhodothermus marinus xylanase Xyn10A, and the identification of the X-2 variant. As compared with the wild-type protein, this engineered module displays higher specificity for the polysaccharide xylan, and a lower preference for binding xylo-oligomers rather than binding the natural decorated polysaccharide. The mode of binding of X-2 differs from other xylan-specific CBMs in that it only has one aromatic residue in the binding site that can make hydrophobic interactions with the sugar rings of the ligand. The evolution of CBM4-2 has thus generated a xylan-binding module with different binding properties to those displayed by CBMs available in Nature.
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Affiliation(s)
| | - Cedric Montanier
- †Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4HH, U.K
| | - Richard B. Tunnicliffe
- ‡Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K
| | - Mike P. Williamson
- ‡Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K
| | - Harry J. Gilbert
- †Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4HH, U.K
| | | | - Mats Ohlin
- *Department of Immunotechnology, Lund University, BMC D13, SE-221 84 Lund, Sweden
- To whom correspondence should be addressed (email )
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Taylor EJ, Gloster TM, Turkenburg JP, Vincent F, Brzozowski AM, Dupont C, Shareck F, Centeno MSJ, Prates JAM, Puchart V, Ferreira LMA, Fontes CMGA, Biely P, Davies GJ. Structure and Activity of Two Metal Ion-dependent Acetylxylan Esterases Involved in Plant Cell Wall Degradation Reveals a Close Similarity to Peptidoglycan Deacetylases. J Biol Chem 2006; 281:10968-75. [PMID: 16431911 DOI: 10.1074/jbc.m513066200] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The enzymatic degradation of plant cell wall xylan requires the concerted action of a diverse enzymatic syndicate. Among these enzymes are xylan esterases, which hydrolyze the O-acetyl substituents, primarily at the O-2 position of the xylan backbone. All acetylxylan esterase structures described previously display a alpha/beta hydrolase fold with a "Ser-His-Asp" catalytic triad. Here we report the structures of two distinct acetylxylan esterases, those from Streptomyces lividans and Clostridium thermocellum, in native and complex forms, with x-ray data to between 1.6 and 1.0 A resolution. We show, using a novel linked assay system with PNP-2-O-acetylxyloside and a beta-xylosidase, that the enzymes are sugar-specific and metal ion-dependent and possess a single metal center with a chemical preference for Co2+. Asp and His side chains complete the catalytic machinery. Different metal ion preferences for the two enzymes may reflect the surprising diversity with which the metal ion coordinates residues and ligands in the active center environment of the S. lividans and C. thermocellum enzymes. These "CE4" esterases involved in plant cell wall degradation are shown to be closely related to the de-N-acetylases involved in chitin and peptidoglycan degradation (Blair, D. E., Schuettelkopf, A. W., MacRae, J. I., and Aalten, D. M. (2005) Proc. Natl. Acad. Sci. U. S. A., 102, 15429-15434), which form the NodB deacetylase "superfamily."
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Affiliation(s)
- Edward J Taylor
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW, United Kingdom
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45
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Kleine J, Liebl W. Comparative characterization of deletion derivatives of the modular xylanase XynA of Thermotoga maritima. Extremophiles 2006; 10:373-81. [PMID: 16550304 DOI: 10.1007/s00792-006-0509-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 01/04/2006] [Indexed: 10/24/2022]
Abstract
The modular Xylanase XynA from Thermotoga maritima consists of five domains (A1-A2-B-C1-C2). Two similar N-terminal domains (A1-A2-) are family 22 carbohydrate-binding modules (CBMs), followed by the catalytic domain (-B-) belonging to glycoside hydrolase family 10, and the C-terminal domains (-C1-C2), which are members of family 9 of CBMs. The gradual deletion of the non-catalytic domains resulted in deletion derivatives (XynADeltaC; XynADeltaA1C and XynADeltaNC) with increased maximum activities (V (max)) at 75 degrees C, pH 6.2. Furthermore, these deletions led to a shift of the optimal NaCl concentration for xylan hydrolysis from 0.25 (XynA) to 0.5 M (XynADeltaNC). In the presence of the family 22 CBMs, the catalytic domain retained more activity in the acidic range of the pH spectrum than without these domains. In addition to the deletion derivatives of XynA, the N-terminal domains A1 and A2 were produced recombinantly, purified, and investigated in binding studies. For soluble xylan preparations, linear beta-1,4-glucans and mixed-linkage beta-1,3-1,4-glucans, only the A2 domain mediated binding, not the A1 domain, in accordance with previous observations. The XynA deletion enzymes lacking the C domains displayed low affinity also to hydroxyethylcellulose and carboxymethylcellulose. With insoluble oat spelt xylan and birchwood xylan as the binding substrates, the highest affinity was observed with XynADeltaC and the lowest affinity with XynADeltaNC. Although the domain A1 did not bind to soluble xylan preparations, the insoluble oat spelt xylan-binding data suggest that this domain does play a role in substrate binding in that it improves the binding to insoluble xylans.
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Affiliation(s)
- Jörg Kleine
- Institut für Mikrobiologie und Genetik, Georg-August-Universität, Grisebachstr. 8, 37077 Göttingen, Germany
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46
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McCartney L, Blake AW, Flint J, Bolam DN, Boraston AB, Gilbert HJ, Knox JP. Differential recognition of plant cell walls by microbial xylan-specific carbohydrate-binding modules. Proc Natl Acad Sci U S A 2006; 103:4765-70. [PMID: 16537424 PMCID: PMC1450244 DOI: 10.1073/pnas.0508887103] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Indexed: 11/18/2022] Open
Abstract
Glycoside hydrolases that degrade plant cell walls have complex molecular architectures in which one or more catalytic modules are appended to noncatalytic carbohydrate-binding modules (CBMs). CBMs promote binding to polysaccharides and potentiate enzymic hydrolysis. Although there are diverse sequence-based families of xylan-binding CBMs, these modules, in general, recognize both decorated and unsubstituted forms of the target polysaccharide, and thus the evolutionary rationale for this diversity is unclear. Using immunohistochemistry to interrogate the specificity of six xylan-binding CBMs for their target polysaccharides in cell walls has revealed considerable differences in the recognition of plant materials between these protein modules. Family 2b and 15 CBMs bind to xylan in secondary cell walls in a range of dicotyledon species, whereas family 4, 6, and 22 CBMs display a more limited capability to bind to secondary cell walls. A family 35 CBM, which displays more restricted ligand specificity against purified xylans than the other five protein modules, reveals a highly distinctive binding pattern to plant material including the recognition of primary cell walls of certain dicotyledons, a feature shared with CBM15. Differences in the specificity of the CBMs toward walls of wheat grain and maize coleoptiles were also evident. The variation in CBM specificity for ligands located in plant cell walls provides a biological rationale for the repertoire of structurally distinct xylan-binding CBMs present in nature, and points to the utility of these modules in probing the molecular architecture of cell walls.
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Affiliation(s)
- Lesley McCartney
- *Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Anthony W. Blake
- *Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - James Flint
- Institute for Cell and Molecular Biosciences, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne NE2 4HH, United Kingdom; and
| | - David N. Bolam
- Institute for Cell and Molecular Biosciences, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne NE2 4HH, United Kingdom; and
| | - Alisdair B. Boraston
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8W 3P6
| | - Harry J. Gilbert
- Institute for Cell and Molecular Biosciences, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne NE2 4HH, United Kingdom; and
| | - J. Paul Knox
- *Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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Stjohn FJ, Rice JD, Preston JF. Paenibacillus sp. strain JDR-2 and XynA1: a novel system for methylglucuronoxylan utilization. Appl Environ Microbiol 2006; 72:1496-506. [PMID: 16461704 PMCID: PMC1392964 DOI: 10.1128/aem.72.2.1496-1506.2006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Accepted: 12/01/2005] [Indexed: 11/20/2022] Open
Abstract
Environmental and economic factors predicate the need for efficient processing of renewable sources of fuels and chemicals. To fulfill this need, microbial biocatalysts must be developed to efficiently process the hemicellulose fraction of lignocellulosic biomass for fermentation of pentoses. The predominance of methylglucuronoxylan (MeGAXn), a beta-1,4 xylan in which 10% to 20% of the xylose residues are substituted with alpha-1,2-4-O-methylglucuronate residues, in hemicellulose fractions of hardwood and crop residues has made this a target for processing and fermentation. A Paenibacillus sp. (strain JDR-2) has been isolated and characterized for its ability to efficiently utilize MeGAXn. A modular xylanase (XynA1) of glycosyl hydrolase family 10 (GH 10) was identified through DNA sequence analysis that consists of a triplicate family 22 carbohydrate binding module followed by a GH 10 catalytic domain followed by a single family 9 carbohydrate binding module and concluding with C-terminal triplicate surface layer homology (SLH) domains. Immunodetection of the catalytic domain of XynA1 (XynA1 CD) indicates that the enzyme is associated with the cell wall fraction, supporting an anchoring role for the SLH modules. With MeGAXn as substrate, XynA1 CD generated xylobiose and aldotetrauronate (MeGAX3) as predominant products. The inability to detect depolymerization products in medium during exponential growth of Paenibacillus sp. strain JDR-2 on MeGAXn, as well as decreased growth rate and yield with XynA1 CD-generated xylooligosaccharides and aldouronates as substrates, indicates that XynA1 catalyzes a depolymerization process coupled to product assimilation. This depolymerization/assimilation system may be utilized for development of biocatalysts to efficiently convert MeGAXn to alternative fuels and biobased products.
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Affiliation(s)
- Franz J Stjohn
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611-0700, USA
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Najmudin S, Guerreiro CIPD, Carvalho AL, Prates JAM, Correia MAS, Alves VD, Ferreira LMA, Romão MJ, Gilbert HJ, Bolam DN, Fontes CMGA. Xyloglucan is recognized by carbohydrate-binding modules that interact with beta-glucan chains. J Biol Chem 2005; 281:8815-28. [PMID: 16314409 DOI: 10.1074/jbc.m510559200] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Enzyme systems that attack the plant cell wall contain noncatalytic carbohydrate-binding modules (CBMs) that mediate attachment to this composite structure and play a pivotal role in maximizing the hydrolytic process. Although xyloglucan, which includes a backbone of beta-1,4-glucan decorated primarily with xylose residues, is a key component of the plant cell wall, CBMs that bind to this polymer have not been identified. Here we showed that the C-terminal domain of the modular Clostridium thermocellum enzyme CtCel9D-Cel44A (formerly known as CelJ) comprises a novel CBM (designated CBM44) that binds with equal affinity to cellulose and xyloglucan. We also showed that accommodation of xyloglucan side chains is a general feature of CBMs that bind to single cellulose chains. The crystal structures of CBM44 and the other CBM (CBM30) in CtCel9D-Cel44A display a beta-sandwich fold. The concave face of both CBMs contains a hydrophobic platform comprising three tryptophan residues that can accommodate up to five glucose residues. The orientation of these aromatic residues is such that the bound ligand would adopt the twisted conformation displayed by cello-oligosaccharides in solution. Mutagenesis studies confirmed that the hydrophobic platform located on the concave face of both CBMs mediates ligand recognition. In contrast to other CBMs that bind to single polysaccharide chains, the polar residues in the binding cleft of CBM44 play only a minor role in ligand recognition. The mechanism by which these proteins are able to recognize linear and decorated beta-1,4-glucans is discussed based on the structures of CBM44 and the other CBMs that bind single cellulose chains.
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Affiliation(s)
- Shabir Najmudin
- Requimte, Departamento de Química, FCT-UNL, 2829-516 Caparica, Portugal, CIISA-Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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49
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Kim KY, Rhee S, Kim SI. Role of the N-Terminal Domain of Endoinulinase from Arthrobacter sp. S37 in Regulation of Enzyme Catalysis. ACTA ACUST UNITED AC 2005; 138:27-33. [PMID: 16046445 DOI: 10.1093/jb/mvi093] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Endoinulinase from Arthrobacter sp. S37 (EnIA), a member of the glycoside hydrolase family 32, is unique in that, unlike other members of the family, it contains a 250-residue N-terminal domain including a "laminin-G like jelly-roll" fold. This unique N-terminal domain is here suggested to be involved in dimerization and catalysis. The essentially inactive nature of enzymes produced by N-terminal truncation (Delta15, Delta45, Delta70, and Delta250) supported the pivotal role of this unique domain in catalysis and the need for its structural integrity. Significant reductions in the enzyme efficiency (kcat/Km) were observed when mutations were introduced at highly conserved tryptophan residues (Trp75 and Trp141) in the laminin-G like jelly-roll fold, implying their involvement in catalysis. Results from size-exclusion chromatography of the native and chimeric enzymes in the presence and absence of the domain suggested that the N-terminal domain could mediate dimerization.
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Affiliation(s)
- Kyoung-Yun Kim
- School of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-742, Korea
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50
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Flint J, Bolam DN, Nurizzo D, Taylor EJ, Williamson MP, Walters C, Davies GJ, Gilbert HJ. Probing the Mechanism of Ligand Recognition in Family 29 Carbohydrate-binding Modules. J Biol Chem 2005; 280:23718-26. [PMID: 15784618 DOI: 10.1074/jbc.m501551200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The recycling of photosynthetically fixed carbon, by the action of microbial plant cell wall hydrolases, is integral to one of the major geochemical cycles and is of considerable industrial importance. Non-catalytic carbohydrate-binding modules (CBMs) play a key role in this degradative process by targeting hydrolytic enzymes to their cognate substrate within the complex milieu of polysaccharides that comprise the plant cell wall. Family 29 CBMs have, thus far, only been found in an extracellular multienzyme plant cell wall-degrading complex from the anaerobic fungus Piromyces equi, where they exist as a CBM29-1:CBM29-2 tandem. Here we present both the structure of the CBM29-1 partner, at 1.5 A resolution, and examine the importance of hydrophobic stacking interactions as well as direct and solvent-mediated hydrogen bonds in the binding of CBM29-2 to different polysaccharides. CBM29 domains display unusual binding properties, exhibiting specificity for both beta-manno- and beta-gluco-configured ligands such as mannan, cellulose, and glucomannan. Mutagenesis reveals that "stacking" of tryptophan residues in the n and n+2 subsites plays a critical role in ligand binding, whereas the loss of tyrosine-mediated stacking in the n+4 subsite reduces, but does not abrogate, polysaccharide recognition. Direct hydrogen bonds to ligand, such as those provided by Arg-112 and Glu-78, play a pivotal role in the interaction with both mannan and cellulose, whereas removal of water-mediated interactions has comparatively little effect on carbohydrate binding. The interactions of CBM29-2 with the O2 of glucose or mannose contribute little to binding affinity, explaining why this CBM displays dual gluco/manno specificity.
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Affiliation(s)
- James Flint
- Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, United Kingdom
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