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Dvorakova H.,Laboratory of NMR spectroscopy
Glycobiology | Year: 2013

In this work, focused on possible application of α-L-fucosidases from bacterial sources in the synthesis of α-L-fucosylated glycoconjugates, several nonpathogenic aerobic bacterial strains were screened for α-L-fucosidase activity. Among them Paenibacillus thiaminolyticus was confirmed as a potent producer of enzyme with the ability to cleave the chromogenic substrate p-nitrophenyl α-L-fucopyranoside. The gene encoding α-L-fucosidase was found using the genomic library of P. thiaminolyticus constructed in the cells of Escherichia coli DH5α and sequenced (EMBL database: FN869117, carbohydrate-active enzymes database: Glycosidase family 29). The enzyme was expressed in the form of polyhistidine-tagged protein (51.2 kDa) in Escherichia coli BL21 (DE3) cells, purified using nickel- nitrilotriacetic acid agarose affinity chromatography and characterized using the chromogenic substrate p-nitrophenyl α-L-fucopyranoside (Km = (0.44 ± 0.02) mmol/L, KS = (83 ± 8) mmol/L (substrate inhibition), pHoptimum = 8.2, toptimum = 48°C). By testing the ability of the enzyme to catalyze the transfer of α-L-fucosyl moiety to different types of acceptor molecules, it was confirmed that the enzyme is able to catalyze the formation of α-L-fucosylated p-nitrophenyl glycopyranosides containing α-D-galactopyranosidic, α-D- glucopyranosidic, α-D-mannopyranosidic or α-L-fucopyranosidic moiety. This enzyme is also able to catalyze α-L-fucosylation of aliphatic alcohols of different lenghs of alkyl chain and hydroxyl group positions (methanol, ethanol, 1-propanol, 2-propanol and 1-octanol) and hydroxyl group-containing amino acid derivatives (N-(tert-butoxycarbonyl)-L-serine methyl ester and N-(tert-butoxycarbonyl)-L-threonine methyl ester). These results indicate the possibility of exploiting this enzyme in the synthesis of different types of α-L-fucosylated molecules representing compounds with potential application in biotechnology and the pharmaceutical industry. © The Author 2013. Published by Oxford University Press.


Botha F.,Institute of Chemical Technology Prague | Budka J.,Institute of Chemical Technology Prague | Eigner V.,ICTP | Hudecek O.,Institute of Chemical Technology Prague | And 3 more authors.
Tetrahedron | Year: 2014

A new type of calixarene-based receptor designed for the recognition of chiral anions was prepared by the introduction of (S)-2-methylbutan-1-ol moieties into the lower rim of calixarene. The immobilization of calixarene skeleton in the 1,3-alternate conformation enabled the construction of a cavity consisting of preorganised ureido functions and chiral substituents in close proximity. This cavity is capable of chiral discrimination of selected anions as demonstrated on d- and l-phenylalaninates. © 2013 Elsevier Ltd. All rights reserved.


Miksatko J.,Institute of Chemical Technology Prague | Eigner V.,UCTP | Dvorakova H.,Laboratory of NMR Spectroscopy | Lhotak P.,Institute of Chemical Technology Prague
Tetrahedron Letters | Year: 2016

An upper rim unsubstituted thiacalix[4]arene immobilised in the cone conformation was regioselectively oxidized to give all possible sulfoxide isomers using NaBO3·4H2O as the oxidizing reagent. Single crystal X-ray analysis undoubtedly assigned the stereochemistry of the sulfoxide group with the oxygen atom pointing toward the upper rim of the thiacalix[4]arene. As revealed by dynamic 1H NMR, the presence of the sulfoxide groups has dramatic consequences on the conformational behavior of the thiacalix[4]arenes. Namely, that the number of sulfoxide groups is inversely proportional to the ΔG barrier of the pinched cone–pinched cone equilibrium as determined by ΔG values 45.4 kJ/mol for monosulfoxide 5 and ΔG <32 kJ/mol for tetrasulfoxide 9. © 2016 Elsevier Ltd


Slavik P.,Institute of Chemical Technology Prague | Dvorakova H.,Laboratory of NMR Spectroscopy | Eigner V.,ICTP | Lhotak P.,Institute of Chemical Technology Prague
Chemical Communications | Year: 2014

The meta-iodo derivative, fixed in the cone conformation, enables the gram-scale preparation of a meta-bridged calix[4]arene. This intermediate, possessing a fluorene moiety within the macrocyclic skeleton, can be regioselectively alkylated on the corresponding methylene bridge to form a unique substitution pattern in classical calixarene chemistry. This journal is © the Partner Organisations 2014.


Flidrova K.,Institute of Chemical Technology Prague | Slavik P.,Institute of Chemical Technology Prague | Eigner V.,ICTP | Dvorakova H.,Laboratory of NMR Spectroscopy | Lhotak P.,Institute of Chemical Technology Prague
Chemical Communications | Year: 2013

The regioselective mercuration of tetraalkylated calix[4]arenes with Hg(OCOCF3)2 leads to the formation of meta-substituted products which enabled Pd-catalysed intramolecular bridging within the calixarene skeleton. Bridged derivatives represent a completely novel substitution pattern in calixarene chemistry with extremely distorted cavities and possible applications in supramolecular chemistry. © 2013 The Royal Society of Chemistry.


Holub J.,Institute of Chemical Technology Prague | Eigner V.,ICTP | Vrzal L.,Laboratory of NMR Spectroscopy | Dvorakova H.,Laboratory of NMR Spectroscopy | Lhotak P.,Institute of Chemical Technology Prague
Chemical Communications | Year: 2013

The introduction of a 2-pyridylsulfoxide moiety into the upper rim of calix[4]arenes enabled the synthesis of unprecedented derivatives with intramolecularly bridged meta positions of two neighbouring aromatic subunits. Palladium-catalysed double C-H activation thus represents a straightforward way to a completely novel type of calixarenes. © The Royal Society of Chemistry 2013.


Hucko M.,Institute of Chemical Technology Prague | Dvorakova H.,Laboratory of NMR Spectroscopy | Eigner V.,ICTP | Lhotak P.,Institute of Chemical Technology Prague
Chemical Communications | Year: 2015

A simple and scalable synthesis of 2,14-dithiacalix[4]arene with alternating bridges (-CH2- and -S-) is reported. Proper selection of the bisphenol-based starting building blocks can provide not only the title compound (58%) but also yet unreported homooxa analogues possessing three different bridging units (-CH2-, -S- and -CH2-O-CH2-) in the molecule. These systems exhibit interesting conformational behaviour allowing for the study of flip-flop motion of the circular hydrogen bond arrays using dynamic NMR techniques. This journal is © The Royal Society of Chemistry 2015.


Botha F.,Institute of Chemical Technology Prague | Eigner V.,UCTP | Dvorakova H.,Laboratory of NMR Spectroscopy | Lhotak P.,Institute of Chemical Technology Prague
New Journal of Chemistry | Year: 2016

Direct mercuration of thiacalix[4]arenes immobilized in the cone or 1,3-alternate conformations followed by Pd-catalyzed arylation was applied to achieve either meta- or para-substitution of basic skeletons. The arylated products represent unique substitution patterns in thiacalixarene chemistry and their conformational behaviour was studied using a combination of dynamic NMR techniques and X-ray crystallography. The usefulness of organomercurial intermediates was also demonstrated through the preparation of thiacalix[4]arene dimers so far unknown in thiacalixarene chemistry. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016.

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