26255-70-9Relevant academic research and scientific papers
Rational design of a thermostable glycoside hydrolase from family 3 introduces β-glycosynthase activity
Pozzo, Tania,Romero-García, Javier,Faijes, Magda,Planas, Antoni,Karlsson, Eva Nordberg
, p. 165 - 175 (2017)
The thermostable β-glucosidase from Thermotoga neapolitana, TnBgl3B, is a monomeric threedomain representative from glycoside hydrolase family 3. By using chemical reactivation with exogenous nucleophiles in previous studies with TnBg13B, the catalytic nucleophile (D242) and corresponding acid/base residue (E458) were determined. Identifying these residues led to the attempt of converting TnBgl3B into a β-glucosynthase, where three nucleophilic variants were created (TnBgl3B-D242G, TnBgl3B-D242A, TnBgl3B-D242S) and all of them failed to exhibit glucosynthase activity. A deeper analysis of the TnBgl3B active site led to the generation of three additional variants, each of which received a single-point mutation. Two of these variants were altered at the -1 subsite (Y210F, W243F) and the third received a substitution near the binding site's aglycone region (N248R). Kinetic evaluation of these three variants revealed that W243F substitution reduced hydrolytic turnover while maintaining KM. This key W243F mutation was then introduced into the original nucleophile variants and the resulting double mutants were successfully converted into β-glucosynthases that were assayed using two separate biosynthetic methods. The first reaction used an α-glucosyl fluoride donor with a 4-nitrophenyl-β-D-glucopyranoside (4NPGlc) acceptor, and the second used 4NPGlc as both the donor and acceptor in the presence of the exogenous nucleophile formate. The primary specificity observed was a β-1,3-linked disaccharide product, while a secondary β-1,4-linked disaccharide product was observed with increased incubation times. Additional analysis revealed that substituting quercetin-3-glycoside for the second reaction's acceptor molecule resulted in the successful production of quercetin-3,4'-diglycosides with yields up to 40%.
Glycosynthases from Thermotoga neapolitana β-glucosidase 1A: A comparison of α-glucosyl fluoride and in situ-generated α-glycosyl formate donors
Pozzo, Tania,Plaza, Merichel,Romero-Garcia, Javier,Faijes, Magda,Karlsson, Eva Nordberg,Planas, Antoni
, p. 132 - 139 (2014/07/21)
TnBgl1A from the thermophile Thermotoga neapolitana is a dimeric β-glucosidase that belongs to glycoside hydrolase family 1 (GH1), with hydrolytic activity through the retaining mechanism, and a broad substrate specificity acting on β-1,4-, β-1,3- and β-1,6-linkages over a range of glyco-oligosaccharides. Three variants of the enzyme (TnBgl1A-E349G, TnBgl1A-E349A and TnBgl1A-E349S), mutated at the catalytic nucleophile, were constructed to evaluate their glycosynthase activity towards oligosaccharide synthesis. Two approaches were used for the synthesis reactions, both of which utilized 4-nitrophenyl β-d-glucopyranoside (4NPGlc) as an acceptor molecule: the first using an α-glucosyl fluoride donor at low temperature (35 °C) in a classical glycosynthase reaction, and the second by in situ generation of the glycosyl donor with (4NPGlc), where formate served as the exogenous nucleophile under higher temperature (70 °C). Using the first approach, TnBgl1A-E349G and TnBgl1A-E349A synthesized disaccharides with β-1,3-linkages in good yields (up to 61%) after long incubations (15 h). However, the GH1 glycosynthase Bgl3-E383A from a mesophilic Streptomyces sp., used as reference enzyme, generated a higher yield at the same temperature with both a shorter reaction time and a lower enzyme concentration. The second approach yielded disaccharides for all three mutants with predominantly β-1,3-linkages (up to 45%) but also β-1,4-linkages (up to 12.5%), after 7 h reaction time. The TnBgl1A glycosynthases were also used for glycosylation of flavonoids, using the two described approaches. Quercetin-3-glycoside was tested as an acceptor molecule and the resultant product was quercetin-3,4′-diglycosides in significantly lower yields, indicating that TnBgl1A preferentially selects 4NPGlc as the acceptor.
Major change in regiospecificity for the exo-1,3-β-glucanase from Candida albicans following its conversion to a glycosynthase
Nakatani,Larsen,Cutfield,Cutfield
, p. 3318 - 3326 (2014/06/10)
The exo-1,3-β-glucanase (Exg) from Candida albicans is involved in cell wall β-d-glucan metabolism and morphogenesis through its hydrolase and transglycosidase activities. Previous work has shown that both these activities strongly favor β-1,3-linkages. The E292S Exg variant displayed modest glycosynthase activity using α-d-glucopyranosyl fluoride (α-GlcF) as the donor and pNP-β-d-glucopyranoside (pNPGlc) as the acceptor but surprisingly showed a marked preference for synthesizing β-1,6-linked over β-1,3- and β-1,4-linked disaccharide products. With pNPXyl as the acceptor, the preference became β-1,4 over β-1,3. The crystal structure of the glycosynthase bound to both of its substrates, α-GlcF and pNPGlc, is the first such ternary complex structure to be determined. The results revealed that the donor bound in the -1 subsite, as expected, while the acceptor was oriented in the +1 subsite to facilitate β-1,6-linkage, thereby supporting the results from solution studies. A second crystal structure containing the major product of glycosynthesis, pNP-gentiobiose, showed that the -1 subsite allows another docking position for the terminal sugar; i.e., one position is set up for catalysis, whereas the other is an intermediate stage prior to the displacement of water from the active site by the incoming sugar hydroxyls. The +1 subsite, an aromatic clamp , permits several different sugar positions and orientations, including a 180°flip that explains the observed variable regiospecificity. The p-nitrophenyl group on the acceptor most likely influences the unexpectedly observed β-1,6-specificity through its interaction with F229. These results demonstrate that tailoring the specificity of a particular glycosynthase depends not only on the chemical structure of the acceptor but also on understanding the structural basis of the promiscuity of the native enzyme.
Glycosynthase with broad substrate specificity-an efficient biocatalyst for the construction of oligosaccharide library
Wei, Jinhua,Lv, Xun,Lue, Yang,Yang, Gangzhu,Fu, Lifeng,Yang, Liu,Wang, Jianjun,Gao, Jianhui,Cheng, Shuihong,Duan, Qian,Jin, Cheng,Li, Xuebing
, p. 2414 - 2419 (2013/05/23)
A versatile glycosynthase (TnG-E338A) with strikingly broad substrate scope has been developed from Thermus nonproteolyticus β-glycosidase (TnG) by using site-directed mutagenesis. The practical utility of this biocatalyst has been demonstrated by the facile generation of a small library containing various oligosaccharides and a steroidal glycoside (total 25 compounds) in up to 100 % isolated yield. Moreover, an array of eight gluco-oligosaccharides has been readily synthesized by the enzyme in a one-pot, parallel reaction, which highlights its potential in the combinatorial construction of a carbohydrate library that will assist glycomic and glycotherapeutic research. Significantly, the enzyme provides a means by which glycosynthase technology may be extended to combinatorial chemistry.
Creation of an α-mannosynthase from a broad glycosidase scaffold
Yamamoto, Keisuke,Davis, Benjamin G.
supporting information; experimental part, p. 7449 - 7453 (2012/09/21)
α-Mannosides made easy: Mutation of a family-GH31 α-glucosidase that displays plasticity to alterations at the 2-OH position of donor substrates created an efficient α-mannoside-synthesizing biocatalyst. A simple fluoride donor reagent was used for the synthesis of a range of mono-α-mannosylated conjugates using the α-mannosynthase displaying low (unwanted) oligomerization activity. Copyright
Acceptor-dependent regioselectivity of glycosynthase reactions by Streptomyces E383A β-glucosidase
Faijes, Magda,Saura-Valls, Marc,Perez, Xavi,Conti, Marta,Planas, Antoni
, p. 2055 - 2065 (2007/10/03)
The nonnucleophilic mutant E383A β-glucosidase from Streptomyces sp. has proven to be an efficient glycosynthase enzyme, catalyzing the condensation of α-glucosyl and α-galactosyl fluoride donors to a variety of acceptors. The enzyme has maximal activity
Rare keto-aldoses from enzymatic oxidation: Substrates and oxidation products of pyranose 2-oxidase
Freimund, Stefan,Huwig, Alexander,Giffhorn, Friedrich,Koepper, Sabine
, p. 2442 - 2455 (2007/10/03)
Pyranose oxidases are known to oxidise D-glucose, D-xylose and L- sorbose to keto-aldoses, biochemically interesting compounds that may also be used for synthetic purposes in a variety of reactions. In this study pyranose oxidase from the basidiomycete Peniophora gigantea was investigated, and it was found that this enzyme is able to oxidise a broad variety of substrates very effectively. In analogy to its natural mode of action, most substrates are oxidised regioselectively in position 2. Certain compounds, however, are converted into 3-keto derivatives, and the enzyme even exhibits transfer potential, that is, disscharides are formed from β-glycosides of higher alcohols. Substrates that may be oxidised at C-2 in yields between 40-98% are D-allose, D-galactose, 6-deoxy-D-glucose, D-gentiobiose, α-D-glucopyranosyl fluoride and the very interesting 3-deoxy-D-glucose. 1,5-Anhydro-D-glucitol (1-deoxy-D-glucose) is very effectively oxidised in position 2 in 98% yield and additionally gives a product of dioxidation at C-2 and C-3 upon prolonged reaction time Selective oxidation at C-3 was found for 2-deoxy-D-glucose in very good yields and for methyl β-D-gluco- and methyl β-galactopyranoside in lower yields. All oxidation products were unequivocally characterised by NMR spectroscopy and/or chemical derivatisation. In addition, the kinetic data of the enzymatic reactions were determined for all substrates. On the basis of these data and the structural characteristics of the substrates, a model for the minimal structural requirements of the enzyme-substrate interaction is suggested. The enzyme presumably uses two different binding modes for the regioselective C-2 and the C-3 oxidations, which are described.
Transglycosylation activity of Bacillus 1,3-1,4-β-D-glucan 4-glucanohydrolases. Enzymic synthesis of alternate 1,3,-1,4-β-D-glucooligosaccharides
Viladot, Josep-Lluis,Moreau, Vincent,Planas, Antoni,Driguez, Hugues
, p. 2383 - 2387 (2007/10/03)
The title enzyme from Bacillus licheniformis has been shown to catalyse the effective autocondensation of β-laminaribiosyl fluoride, and lead to alternate 1,3-1,4-β-D-glucotetraose and -glucohexaose products. The transglycosylation using the same donor an
p-NITROPHENYL 2-, AND 3-O-α-D-MANNOPYRANOSYL-α-D-MANNOPYRANOSIDE
Ekborg, Goeran,Glaudemans, Cornelis P. J.
, p. 83 - 88 (2007/10/02)
p-Nitrophenyl 3- and 2-O-benzoyl-4,6-O-benzylidene-α-D-mannopyranoside were each condensed with 2,3,4,6-tetra-O-benzoyl-α-D-mannopyranosyl bromide, and the products were deprotected, to yield, respectively, p-nitrophenyl 2- and 3-O-mannopyranosyl-α-D-mann
