51
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Ortiz-Soto ME, Possiel C, Görl J, Vogel A, Schmiedel R, Seibel J. Impaired coordination of nucleophile and increased hydrophobicity in the +1 subsite shift levansucrase activity towards transfructosylation. Glycobiology 2017; 27:755-765. [PMID: 28575294 PMCID: PMC5881714 DOI: 10.1093/glycob/cwx050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 12/26/2022] Open
Abstract
Bacterial levansucrases produce β(2,6)-linked levan-type polysaccharides using sucrose or sucrose analogs as donor/acceptor substrates. However, the dominant reaction of Bacillus megaterium levansucrase (Bm-LS) is hydrolysis. Single domain levansucrases from Gram-positive bacteria display a wide substrate-binding pocket with open access to water, challenging engineering for transfructosylation-efficient enzymes. We pursued a shift in reaction specificity by either modifying the water distribution in the active site or the coordination of the catalytic acid/base (E352) and the nucleophile (D95), thus affecting the fructosyl-transfer rate and allowing acceptors other than water to occupy the active site. Two serine (173/422) and two water-binding tyrosine (421/439) residues located in the first shell of the catalytic pocket were modified. Library variants of S173, Y421 and S422, which coordinate the position of D95 and E352, show increased transfructosylation (30–200%) and modified product spectra. Substitutions at position 422 have a higher impact on sucrose affinity, while changes at position 173 and 421 have a strong effect on the overall catalytic rate. As most retaining glycoside hydrolases (GHs) Bm-LS catalyzes hydrolysis and transglycosylation via a double displacement reaction involving two-transition states (TS1 and TS2). Hydrogen bonds of D95 with the side chains of S173 and S422 contribute a total of 2.4 kcal mol−1 to TS1 stabilization, while hydrogen bonds between invariant Y421, E352 and the glucosyl C-2 hydroxyl-group of sucrose contribute 2.15 kcal mol−1 stabilization. Changes at Y439 render predominantly hydrolytic variants synthesizing shorter oligosaccharides.
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Affiliation(s)
- Maria Elena Ortiz-Soto
- Institute of Organic Chemistry, University of Würzburg, Würzburg, Am Hubland 97074, Germany
| | - Christian Possiel
- Institute of Organic Chemistry, University of Würzburg, Würzburg, Am Hubland 97074, Germany
| | - Julian Görl
- Institute of Organic Chemistry, University of Würzburg, Würzburg, Am Hubland 97074, Germany
| | - Andreas Vogel
- c-LEcta GmbH, Leipzig, Perlickstr. 5, 04103, Germany
| | | | - Jürgen Seibel
- Institute of Organic Chemistry, University of Würzburg, Würzburg, Am Hubland 97074, Germany
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52
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Xu W, Yu S, Liu Q, Zhang T, Jiang B, Mu W. Enzymatic Production of Melibiose from Raffinose by the Levansucrase from Leuconostoc mesenteroides B-512 FMC. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:3910-3918. [PMID: 28453942 DOI: 10.1021/acs.jafc.7b01265] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Melibiose, which is an important reducing disaccharide formed by α-1,6 linkage between galactose and glucose, has been proven to have beneficial applications in both medicine and agriculture. In this study, a characterized levansucrase from Leuconostoc mesenteroides B-512 FMC was further used to study the bioproduction of melibiose from raffinose. The reaction conditions were optimized for melibiose synthesis. The optimal pH, temperature, substrate concentration, ratio of substrates, and units of enzymes were determined as pH 6.0, 45 °C, 210 g/L, 1:1 (210 g/L:210 g/L), and 5 U/mL, respectively. The transfructosylation product of raffinose was determined to be melibiose by FTIR and NMR. A high raffinose concentration was found to strongly favor the production of melibiose. When 210 g/L raffinose and 210 g/L lactose were catalyzed using 5 U/mL purified levansucrase at pH 6.0 and 45 °C, the maximal yield of melibiose was 88 g/L.
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Affiliation(s)
- Wei Xu
- State Key Laboratory of Food Science and Technology, Jiangnan University , Wuxi, Jiangsu 214122, China
| | - Shuhuai Yu
- State Key Laboratory of Food Science and Technology, Jiangnan University , Wuxi, Jiangsu 214122, China
| | - Qian Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University , Wuxi, Jiangsu 214122, China
| | - Tao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University , Wuxi, Jiangsu 214122, China
| | - Bo Jiang
- State Key Laboratory of Food Science and Technology, Jiangnan University , Wuxi, Jiangsu 214122, China
- Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University , Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University , Wuxi, Jiangsu 214122, China
- Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University , Wuxi, Jiangsu 214122, China
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53
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González-Garcinuño Á, Tabernero A, Domínguez Á, Galán MA, Martin del Valle EM. Levan and levansucrases: Polymer, enzyme, micro-organisms and biomedical applications. BIOCATAL BIOTRANSFOR 2017. [DOI: 10.1080/10242422.2017.1314467] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Antonio Tabernero
- Department of Chemical Engineering, University of Salamanca, Salamanca, Spain
| | - Ángel Domínguez
- Department of Microbiology and Genetics, University of Salamanca, Salamanca, Spain
| | - Miguel A. Galán
- Department of Chemical Engineering, University of Salamanca, Salamanca, Spain
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54
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Erdal Ö, Kaplan-Türköz B, Taştan Ö, Göksungur Y. Levansucrase production by Zymomonas mobilis
: Optimization of process parameters and fructooligosaccharide production. J Food Biochem 2017. [DOI: 10.1111/jfbc.12361] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Özlem Erdal
- Department of Food Engineering, Faculty of Engineering; Ege University; 35100 Bornova, İzmir Turkey
| | - Burcu Kaplan-Türköz
- Department of Food Engineering, Faculty of Engineering; Ege University; 35100 Bornova, İzmir Turkey
| | - Özge Taştan
- Department of Food Engineering, Faculty of Engineering; Ege University; 35100 Bornova, İzmir Turkey
| | - Yekta Göksungur
- Department of Food Engineering, Faculty of Engineering; Ege University; 35100 Bornova, İzmir Turkey
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55
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Gao S, Qi X, Hart DJ, Gao H, An Y. Expression and Characterization of Levansucrase from Clostridium acetobutylicum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:867-871. [PMID: 28075130 DOI: 10.1021/acs.jafc.6b05165] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The Clostridium acetobutylicum gene Ca-SacB encoding levansucrase was cloned and expressed in Escherichia coli. Ca-SacB is composed of 1287 bp and encodes 428 amino acid residues, which could convert 150 mmol/L sucrose to levan with the liberation of glucose. The optimum pH and temperature of this enzyme for levan formation were pH 6 and 60 °C, respectively. Levansucrase activity of Ca-SacB was completely abolished by 5 mmol/L Ag+ and Hg2+. The Km and Vmax values for levansucrase were calculated to be 64 mmol/L and 190 μmol/min/mg, respectively. Interestingly, Ca-SacB was found to have high product specificity, and no fructooligosaccharide was identified in the product, indicating that Ca-SacB may be valuable for industrial production of levan. In addition, Ca-SacB is the first characterized levansucrase isolated from an anaerobic bacterium, which should be valuable for exploring new enzyme resources and deepening the understanding of the catalytic mechanisms of levansucrases.
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Affiliation(s)
| | - Xianghui Qi
- School of Food and Biological Engineering, Jiangsu University , Zhenjiang 212000, China
| | - Darren J Hart
- Institut de Biologie Structurale (IBS), CEA, CNRS, University Grenoble Alpes , Grenoble 38044, France
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56
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Öner ET, Hernández L, Combie J. Review of Levan polysaccharide: From a century of past experiences to future prospects. Biotechnol Adv 2016; 34:827-844. [DOI: 10.1016/j.biotechadv.2016.05.002] [Citation(s) in RCA: 203] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 05/01/2016] [Accepted: 05/04/2016] [Indexed: 01/24/2023]
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57
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Raga-Carbajal E, Carrillo-Nava E, Costas M, Porras-Dominguez J, López-Munguía A, Olvera C. Size product modulation by enzyme concentration reveals two distinct levan elongation mechanisms inBacillus subtilislevansucrase. Glycobiology 2015; 26:377-85. [DOI: 10.1093/glycob/cwv112] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 11/25/2015] [Indexed: 11/13/2022] Open
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58
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Li M, Seo S, Karboune S. Bacillus amyloliquefaciens levansucrase-catalyzed the synthesis of fructooligosaccharides, oligolevan and levan in maple syrup-based reaction systems. Carbohydr Polym 2015; 133:203-12. [DOI: 10.1016/j.carbpol.2015.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 07/05/2015] [Accepted: 07/07/2015] [Indexed: 11/24/2022]
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59
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The crystal structure of Erwinia amylovora levansucrase provides a snapshot of the products of sucrose hydrolysis trapped into the active site. J Struct Biol 2015. [DOI: 10.1016/j.jsb.2015.07.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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60
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Recent novel applications of levansucrases. Appl Microbiol Biotechnol 2015; 99:6959-69. [DOI: 10.1007/s00253-015-6797-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Revised: 06/22/2015] [Accepted: 06/24/2015] [Indexed: 01/12/2023]
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61
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Optimization of levansucrase/endo-inulinase bi-enzymatic system for the production of fructooligosaccharides and oligolevans from sucrose. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.molcatb.2014.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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62
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Díez-Municio M, Herrero M, Olano A, Moreno FJ. Synthesis of novel bioactive lactose-derived oligosaccharides by microbial glycoside hydrolases. Microb Biotechnol 2014; 7:315-31. [PMID: 24690139 PMCID: PMC4241725 DOI: 10.1111/1751-7915.12124] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 02/21/2014] [Accepted: 02/23/2014] [Indexed: 12/17/2022] Open
Abstract
Prebiotic oligosaccharides are increasingly demanded within the Food Science domain because of the interesting healthy properties that these compounds may induce to the organism, thanks to their beneficial intestinal microbiota growth promotion ability. In this regard, the development of new efficient, convenient and affordable methods to obtain this class of compounds might expand even further their use as functional ingredients. This review presents an overview on the most recent interesting approaches to synthesize lactose-derived oligosaccharides with potential prebiotic activity paying special focus on the microbial glycoside hydrolases that can be effectively employed to obtain these prebiotic compounds. The most notable advantages of using lactose-derived carbohydrates such as lactosucrose, galactooligosaccharides from lactulose, lactulosucrose and 2-α-glucosyl-lactose are also described and commented.
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Affiliation(s)
- Marina Díez-Municio
- Instituto de Investigación en Ciencias de la Alimentación, CIAL (CSIC-UAM), CEI (UAM+CSIC)C/ Nicolás Cabrera 9, Madrid, 28049, Spain
| | - Miguel Herrero
- Instituto de Investigación en Ciencias de la Alimentación, CIAL (CSIC-UAM), CEI (UAM+CSIC)C/ Nicolás Cabrera 9, Madrid, 28049, Spain
| | - Agustín Olano
- Instituto de Investigación en Ciencias de la Alimentación, CIAL (CSIC-UAM), CEI (UAM+CSIC)C/ Nicolás Cabrera 9, Madrid, 28049, Spain
| | - F Javier Moreno
- Instituto de Investigación en Ciencias de la Alimentación, CIAL (CSIC-UAM), CEI (UAM+CSIC)C/ Nicolás Cabrera 9, Madrid, 28049, Spain
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63
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Synthesis of fructooligosaccharides and oligolevans by the combined use of levansucrase and endo-inulinase in one-step bi-enzymatic system. INNOV FOOD SCI EMERG 2014. [DOI: 10.1016/j.ifset.2013.12.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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64
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Enhancing thermostability and the structural characterization of Microbacterium saccharophilum K-1 β-fructofuranosidase. Appl Microbiol Biotechnol 2014; 98:6667-77. [PMID: 24633372 DOI: 10.1007/s00253-014-5645-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/19/2014] [Accepted: 02/25/2014] [Indexed: 10/25/2022]
Abstract
A β-fructofuranosidase from Microbacterium saccharophilum K-1 (formerly known as Arthrobacter sp. K-1) is useful for producing the sweetener lactosucrose (4(G)-β-D-galactosylsucrose). Thermostability of the β-fructofuranosidase was enhanced by random mutagenesis and saturation mutagenesis. Clones with enhanced thermostability included mutations at residues Thr47, Ser200, Phe447, Phe470, and Pro500. In the highest stability mutant, T47S/S200T/F447P/F470Y/P500S, the half-life at 60 °C was 182 min, 16.5-fold longer than the wild-type enzyme. A comparison of the crystal structures of the full-length wild-type enzyme and three mutants showed that various mechanisms appear to be involved in thermostability enhancement. In particular, the replacement of Phe447 with Val or Pro induced a conformational change in an adjacent residue His477, which results in the formation of a new hydrogen bond in the enzyme. Although the thermostabilization mechanisms of the five residue mutations were explicable on the basis of the crystal structures, it appears to be difficult to predict which amino acid residues should be modified to obtain thermostabilized enzymes.
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65
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Caputi L, Nepogodiev SA, Malnoy M, Rejzek M, Field RA, Benini S. Biomolecular characterization of the levansucrase of Erwinia amylovora, a promising biocatalyst for the synthesis of fructooligosaccharides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:12265-12273. [PMID: 24274651 DOI: 10.1021/jf4023178] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Erwinia amylovora is a plant pathogen that affects Rosaceae, such as apple and pear. In E. amylovora the fructans, produced by the action of a levansucrase (EaLsc), play a role in virulence and biofilm formation. Fructans are bioactive compounds, displaying health-promoting properties in their own right. Their use as food and feed supplements is increasing. In this study, we investigated the biomolecular properties of EaLsc using HPAEC-PAD, MALDI-TOF MS, and spectrophotometric assays. The enzyme, which was heterologously expressed in Escherichia coli in high yield, was shown to produce mainly fructooligosaccharides (FOSs) with a degree of polymerization between 3 and 6. The kinetic properties of EaLsc were similar to those of other phylogenetically related Gram-negative bacteria, but the good yield of FOSs, the product spectrum, and the straightforward production of the enzyme suggest that EaLsc is an interesting biocatalyst for future studies aimed at producing tailor-made fructans.
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Affiliation(s)
- Lorenzo Caputi
- Laboratory of Bioorganic Chemistry and Crystallography, Faculty of Science and Technology, Free University of Bolzano , Piazza Università 5, 39100 Bolzano, Italy
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66
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Mardo K, Visnapuu T, Vija H, Elmi T, Alamäe T. Mutational analysis of conserved regions harboring catalytic triad residues of the levansucrase protein encoded by the
lsc‐3
gene (
lsc3
) of
Pseudomonas syringae
pv. tomato
DC
3000. Biotechnol Appl Biochem 2013; 61:11-22. [DOI: 10.1002/bab.1129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 05/22/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Karin Mardo
- Institute of Molecular and Cell Biology University of Tartu Tartu Estonia
| | - Triinu Visnapuu
- Institute of Molecular and Cell Biology University of Tartu Tartu Estonia
| | - Heiki Vija
- National Institute of Chemical Physics and Biophysics Tallinn Estonia
| | - Triin Elmi
- Institute of Molecular and Cell Biology University of Tartu Tartu Estonia
| | - Tiina Alamäe
- Institute of Molecular and Cell Biology University of Tartu Tartu Estonia
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67
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Inthanavong L, Tian F, Khodadadi M, Karboune S. Properties of Geobacillus stearothermophilus levansucrase as potential biocatalyst for the synthesis of levan and fructooligosaccharides. Biotechnol Prog 2013; 29:1405-15. [PMID: 23926090 DOI: 10.1002/btpr.1788] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/10/2013] [Indexed: 11/07/2022]
Abstract
The production of levansucrase (LS) by thermophilic Geobacillus stearothermophilus was investigated. LS production was more effective in the presence of sucrose (1%, w/v) than fructose, glucose, glycerol or raffinose. The results (Top 57°C; stable for 6 h at 47°C) indicate the high stability of the transfructosylation activity of G. stearothermophilus LS as compared with LSs from other microbial sources. Contrary to temperature, the pH had a significant effect on the selectivity of G. stearothermophilus LS-catalyzed reaction, favoring the transfructosylation reaction in the pH range of 6.0-6.5. The kinetic parameter study revealed that the catalytic efficiency of transfructosylation activity was higher as compared with the hydrolytic one. In addition to levan, G. stearothermophilus LS synthesized fructooligosaccharides in the presence of sucrose as the sole substrate. The results also demonstrated the wide acceptor specificity of G. stearothermophilus LS with maltose being the best fructosyl acceptor. This study is the first on the catalytic properties and the acceptor specificity of LS from G. stearothermophilus.
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Affiliation(s)
- Lotthida Inthanavong
- Dept. of Food Science and Agricultural Chemistry, McGill University, 21,111 Lakeshore, Ste-Anne de Bellevue, Quebec H9X 3V9, Canada
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68
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Caputi L, Cianci M, Benini S. Cloning, expression, purification, crystallization and preliminary X-ray analysis of EaLsc, a levansucrase from Erwinia amylovora. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:570-3. [PMID: 23695580 DOI: 10.1107/s1744309113010750] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/19/2013] [Indexed: 11/10/2022]
Abstract
The Gram-negative bacterium Erwinia amylovora is a destructive pathogen of Rosaceae. During infection, E. amylovora produces the exopolysaccharide levan, which contributes to the occlusion of plant vessels, causing the wilting of shoots. Levan is a fructose polymer that is synthesized by multifunctional enzymes called levansucrases. The levansucrase from E. amylovora (EaLsc) was heterologously expressed as a GST-fusion protein in Escherichia coli, purified and crystallized after tag removal. The protein crystallized in space group P21212. X-ray diffraction data were acquired to 2.77 Å resolution. The structure of the enzyme was solved by molecular replacement. The asymmetric unit contains eight enzyme molecules, giving a solvent content of 58.74% and a Matthews coefficient of 2.98 Å(3) Da(-1).
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Affiliation(s)
- Lorenzo Caputi
- Laboratory of Bioorganic Chemistry and Crystallography, Faculty of Science and Technology, Free University of Bolzano, Piazza Università 5, 39100 Bolzano, Italy
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69
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Tonozuka T, Tamaki A, Yokoi G, Miyazaki T, Ichikawa M, Nishikawa A, Ohta Y, Hidaka Y, Katayama K, Hatada Y, Ito T, Fujita K. Crystal structure of a lactosucrose-producing enzyme, Arthrobacter sp. K-1 β-fructofuranosidase. Enzyme Microb Technol 2012; 51:359-65. [DOI: 10.1016/j.enzmictec.2012.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 08/08/2012] [Accepted: 08/08/2012] [Indexed: 10/28/2022]
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70
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Abstract
Background It is well known that carbohydrates play fundamental roles in cell signaling and infection processes as well as tumor formation and progression. However, the interaction pathways and cellular receptors targeted by carbohydrates and glycoconjugates remain poorly examined and understood. This lack of research stems, at least to a major part, from accessibility problems of large, branched oligosaccharides. Results To test glycan - cell interactions in vitro, a variety of tailored oligosaccharides was synthesized chemo-enzymatically. Glycosyltransferases from the GRAS organisms Bacillus megaterium (SacB) and Aspergillus niger (Suc1) were used in this study. Substrate engineering of these glycosyltransferases generally acting on sucrose leads to the controlled formation of novel tailored di-, tri- and tetrasaccharides. Already industrially used as prebiotics in functional food, the immunogenic potential of novel oligosaccharides was characterized in this study. A differential secretion of CXCL8 and CCL2 was observed upon oligosaccharide co-cultivation with colorectal epithelial Caco-2 cells. Conclusion Pure carbohydrates are able to stimulate a cytokine response in human endothelial cells in vitro. The type and amount of cytokine secretion depends on the type of co-cultivated oligosaccharide.
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71
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Anwar MA, Leemhuis H, Pijning T, Kralj S, Dijkstra BW, Dijkhuizen L. The role of conserved inulosucrase residues in the reaction and product specificity ofLactobacillus reuteriinulosucrase. FEBS J 2012; 279:3612-3621. [DOI: 10.1111/j.1742-4658.2012.08721.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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72
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Park J, Kim MI, Park YD, Shin I, Cha J, Kim CH, Rhee S. Structural and functional basis for substrate specificity and catalysis of levan fructotransferase. J Biol Chem 2012; 287:31233-41. [PMID: 22810228 DOI: 10.1074/jbc.m112.389270] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Levan is β-2,6-linked polymeric fructose and serves as reserve carbohydrate in some plants and microorganisms. Mobilization of fructose is usually mediated by enzymes such as glycoside hydrolase (GH), typically releasing a monosaccharide as a product. The enzyme levan fructotransferase (LFTase) of the GH32 family catalyzes an intramolecular fructosyl transfer reaction and results in production of cyclic difructose dianhydride, thus exhibiting a novel substrate specificity. The mechanism by which LFTase carries out these functions via the structural fold conserved in the GH32 family is unknown. Here, we report the crystal structure of LFTase from Arthrobacter ureafaciens in apo form, as well as in complexes with sucrose and levanbiose, a difructosacchride with a β-2,6-glycosidic linkage. Despite the similarity of its two-domain structure to members of the GH32 family, LFTase contains an active site that accommodates a difructosaccharide using the -1 and -2 subsites. This feature is unique among GH32 proteins and is facilitated by small side chain residues in the loop region of a catalytic β-propeller N-domain, which is conserved in the LFTase family. An additional oligosaccharide-binding site was also characterized in the β-sandwich C-domain, supporting its role in carbohydrate recognition. Together with functional analysis, our data provide a molecular basis for the catalytic mechanism of LFTase and suggest functional variations from other GH32 family proteins, notwithstanding the conserved structural elements.
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Affiliation(s)
- Jinseo Park
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
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73
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Yuan S, Le Roy K, Venken T, Lammens W, Van den Ende W, De Maeyer M. pKa modulation of the acid/base catalyst within GH32 and GH68: a role in substrate/inhibitor specificity? PLoS One 2012; 7:e37453. [PMID: 22662155 PMCID: PMC3360783 DOI: 10.1371/journal.pone.0037453] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 04/21/2012] [Indexed: 11/18/2022] Open
Abstract
Glycoside hydrolases of families 32 (GH32) and 68 (GH68) belong to clan GH-J, containing hydrolytic enzymes (sucrose/fructans as donor substrates) and fructosyltransferases (sucrose/fructans as donor and acceptor substrates). In GH32 members, some of the sugar substrates can also function as inhibitors, this regulatory aspect further adding to the complexity in enzyme functionalities within this family. Although 3D structural information becomes increasingly available within this clan and huge progress has been made on structure-function relationships, it is not clear why some sugars bind as inhibitors without being catalyzed. Conserved aspartate and glutamate residues are well known to act as nucleophile and acid/bases within this clan. Based on the available 3D structures of enzymes and enzyme-ligand complexes as well as docking simulations, we calculated the pKa of the acid-base before and after substrate binding. The obtained results strongly suggest that most GH-J members show an acid-base catalyst that is not sufficiently protonated before ligand entrance, while the acid-base can be fully protonated when a substrate, but not an inhibitor, enters the catalytic pocket. This provides a new mechanistic insight aiming at understanding the complex substrate and inhibitor specificities observed within the GH-J clan. Moreover, besides the effect of substrate entrance on its own, we strongly suggest that a highly conserved arginine residue (in the RDP motif) rather than the previously proposed Tyr motif (not conserved) provides the proton to increase the pKa of the acid-base catalyst.
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Affiliation(s)
- Shuguang Yuan
- Laboratory of Molecular Plant Physiology, Institute of Botany and Microbiology, KU Leuven, Heverlee, Belgium
- Laboratory for Biomolecular Modelling, Department of Chemistry, Division of Biochemistry, Molecular and Structural Biology, KU Leuven, Heverlee, Belgium
| | - Katrien Le Roy
- Laboratory of Molecular Plant Physiology, Institute of Botany and Microbiology, KU Leuven, Heverlee, Belgium
| | - Tom Venken
- Laboratory for Biomolecular Modelling, Department of Chemistry, Division of Biochemistry, Molecular and Structural Biology, KU Leuven, Heverlee, Belgium
| | - Willem Lammens
- Laboratory of Molecular Plant Physiology, Institute of Botany and Microbiology, KU Leuven, Heverlee, Belgium
| | - Wim Van den Ende
- Laboratory of Molecular Plant Physiology, Institute of Botany and Microbiology, KU Leuven, Heverlee, Belgium
- * E-mail: (WV); (MDM)
| | - Marc De Maeyer
- Laboratory for Biomolecular Modelling, Department of Chemistry, Division of Biochemistry, Molecular and Structural Biology, KU Leuven, Heverlee, Belgium
- * E-mail: (WV); (MDM)
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Mechanism-Oriented Redesign of an Isomaltulose Synthase to an Isomelezitose Synthase by Site-Directed Mutagenesis. Chembiochem 2011; 13:149-56. [DOI: 10.1002/cbic.201100576] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Indexed: 11/07/2022]
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75
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Visnapuu T, Mardo K, Mosoarca C, Zamfir AD, Vigants A, Alamäe T. Levansucrases from Pseudomonas syringae pv. tomato and P. chlororaphis subsp. aurantiaca: Substrate specificity, polymerizing properties and usage of different acceptors for fructosylation. J Biotechnol 2011; 155:338-49. [DOI: 10.1016/j.jbiotec.2011.07.026] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 06/03/2011] [Accepted: 07/20/2011] [Indexed: 11/25/2022]
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76
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Pijning T, Anwar MA, Böger M, Dobruchowska JM, Leemhuis H, Kralj S, Dijkhuizen L, Dijkstra BW. Crystal structure of inulosucrase from Lactobacillus: insights into the substrate specificity and product specificity of GH68 fructansucrases. J Mol Biol 2011; 412:80-93. [PMID: 21801732 DOI: 10.1016/j.jmb.2011.07.031] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 07/13/2011] [Accepted: 07/15/2011] [Indexed: 11/27/2022]
Abstract
Fructansucrases (FSs) catalyze a transfructosylation reaction with sucrose as substrate to produce fructo-oligosaccharides and fructan polymers that contain either β-2,1 glycosidic linkages (inulin) or β-2,6 linkages (levan). Levan-synthesizing FSs (levansucrases) have been most extensively investigated, while detailed information on inulosucrases is limited. Importantly, the molecular basis of the different product specificities of levansucrases and inulosucrases is poorly understood. We have elucidated the three-dimensional structure of a truncated active bacterial GH68 inulosucrase, InuJ of Lactobacillus johnsonii NCC533 (residues 145-708), in its apo form, with a bound substrate (sucrose), and with a transfructosylation product. The sucrose binding pocket and the sucrose binding mode are virtually identical with those of GH68 levansucrases, confirming that both enzyme types use the same fully conserved structural framework for the binding and cleavage of the donor substrate sucrose in the active site. The binding mode of the first transfructosylation product 1-kestose (Fru-β(2-1)-Fru-α(2-1)-Glc, where Fru=fructose and Glc=glucose) in subsites -1 to +2 shows for the first time how inulin-type fructo-oligosaccharide bind in GH68 FS and how an inulin-type linkage can be formed. Surprisingly, observed interactions with the sugar in subsites +1 and +2 are provided by residues that are also present in levansucrases. The binding mode of 1-kestose and the presence of a more distant sucrose binding site suggest that residues beyond the +2 subsite, in particular residues from the nonconserved 1B-1C loop, determine product linkage type specificity in GH68 FSs.
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Affiliation(s)
- Tjaard Pijning
- Laboratory of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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