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In the absence of naturally available galactofuranose-specific lectin, we report herein the bioengineering of GalfNeoLect, from the first cloned wild-type galactofuranosidase (Streptomyces sp. strain JHA19), which recognises and binds a single monosaccharide that is only related to nonmammalian species, usually pathogenic microorganisms. We kinetically characterised the GalfNeoLect to confirm attenuation of hydrolytic activity and used competitive inhibition assay, with close structural analogues of Galf, to show that it conserved interaction with its original substrate. We synthetised the bovine serum albumin-based neoglycoprotein (GalfNGP), carrying the multivalent Galf units, as a suitable ligand and high-avidity system for the recognition of GalfNeoLect which we successfully tested directly with the galactomannan spores of Aspergillus brasiliensis (ATCC 16404). Altogether, our results indicate that GalfNeoLect has the necessary versatility and plasticity to be used in both research and diagnostic lectin-based applications. [ABSTRACT FROM AUTHOR]

This study unveils an innovative method for synthesizing coumarin S-glycosides, employing original biocatalysts able to graft diverse carbohydrate structures onto 7-mercapto-4-methyl-coumarin in one-pot reactions. The fluorescence properties of the generated thio-derivatives were assessed, providing valuable insights into their potential applications in biological imaging or sensing. In addition, the synthesized compounds exhibited no cytotoxicity across various human cell lines. This research presents a promising avenue for the development of coumarin S-glycosides, paving the way for their application in diverse biomedical research areas. [ABSTRACT FROM AUTHOR]

NMR spectroscopy is a powerful tool for characterizing and identifying molecules and nowadays is even used to characterize complex systems in biology. In the experiment presented here, students learned how to apply this modern technique to probe interactions between small molecules and proteins. With the use of simple organic synthesis, students prepared different analogues of the well-known anxiolytic drug, nitrazepam. This study constituted the students' first approach into the drug-discovery field and encouraged the students to think about how to improve the design of drugs in a rational way. (Contains 3 figures.)

In the present study, new 2-phenyl-5,6,7,8-tetrahydroimidazo [1,2-b]pyridazines bearing sulfonamides were synthesized, characterized and evaluated for their anticancer activities. The structures of these derivatives were elucidated by 1H NMR, 13C NMR, infrared and high-resolution mass spectrometry for further validation of the target compound structures. The anticancer activities of the new molecules were evaluated against five human cancer cell lines, including A-549, Hs-683, MCF-7, SK-MEL-28 and B16-F10 cell lines using 5-fluorouracil and etoposide as the reference drugs. Among the tested compounds, 4e and 4f exhibited excellent activities in the same range of the positive controls, 5-fluorouracil and etoposide, against MCF-7 and SK-MEL-28 cancer cell lines, with IC50 values ranging from 1 to 10 μM. The molecular docking studies of 4e and 4f showed a strong binding with some kinases, which are linked to MCF-7 and SK-MEL-28 cancer cell lines. [ABSTRACT FROM AUTHOR]

The analysis of various synthetic substrates and homology modeling helps in explaining the active site of myo-inositol dehydrogenase (IDH) from Bacillus subtilis. The study helps in examining the structure-function relationships of the homologous dehydrogenases active in bacteria.

Inositol dehydrogenase (EC 1.1.1.18) from Bacillus subtilis catalyzes the oxidation of myo-inositol to scylloinosose by transfer of the equatorial hydride of the substrate to [NAD.sup.+]. This is a key enzyme in the metabolism of myo-inositol, a primary carbon source for soil bacteria. In light of our recent discovery that the enzyme has a broad substrate spectrum while maintaining high stereoselectivity, we seek a more thorough understanding of the enzyme and its active site. We have examined the kinetics of the recombinant enzyme, and synthesized fluorinated substrate analogues as competitive inhibitors. We have evaluated all rate constants in the ordered, sequential Bi Bi mechanism. No steady-state kinetic isotope effect is observed using myo-[2-²H]-inositol, indicating that the chemical step of the reaction is not rate-limiting. We have synthesized the substrate analogs 2-deoxy-2-fluoro-myo-inositol, its equatorial analog 1-deoxy-1-fluoro-scyllo-inositol, the gem-difluorinated analog 1-deoxy-1,1-difluoro-scyllo-inositol, and the sugar analog α-D-glucosyl fluoride. Of these, 1-deoxy-1-fluoro-scyllo-inositol showed no inhibition, while all others tested had [K.sub.i] values comparable to the [K.sub.m] values of the analogous substrates myo-inositol and α-D-glucose. Key words: inositol dehydrogenase, enzyme mechanism, kinetics, competitive inhibitor, substrate analogue. La deshydrogenase de l'inositol (EC 1.1.1.18) du Bacillus subtilis catalyse l'oxydation du myo-inositol en scyllo-inosose par le transfert d'un hydrure equatorial du substrat vers la [NAD.sup.+]. C'est un enzyme cle dans le metabolisme du myo-inositol, une source de carbone primaire pour les bacteries du sol. Compte tenu de notre decouverte recente 'l'effet que l'enzyme peut agir sur un large eventail de substrats tout en maintenant une stereoselectivite elevee, une etude plus approfondie a ete entreprise pour mieux comprendre cet enzyme et son site actif. A cette fin, on a etudie la cinetique de l'enzyme recombinant et on a synthetise des analogues fluores de substrats comme inhibiteurs competitifs. On a evalue toutes les constantes de vitesse dans le mecanisme Bi Bi, ordonne et sequentiel. On n'a pas observe d'effet isotopique cinetique a l'etat stationnaire lorsqu'on a etudie le myo-[2-²H]-inositol; cette observation indique que l'etape chimique n'est pas cinetiquement limitante. On a aussi synthetise les analogues de substrats 2-desoxy-2-fluoro-myo-inositol, son analogue equatorial 1-desoxy-1-fluoro-scyllo-inositol, son analogue gem-difluore 1desoxy-1,1-d inositol et le sucre analogue fluorure de α-D-glucosyle. De tous ces composes, le 1-desoxy-1fluoro-scyllo-inositol ne presente pas d'inhibition alors que, avec tous les autres composes evalues, les valeurs de [K.sub.i] sont comparables aux valeurs de [K.sub.m] des substrats analogues du myo-inositol et du α-D-glucose. Mots cles : inositol, deshydrogenase, mecanisme d'enzyme, cinetique, inhibition competitive, analogue de substrat. [Traduit par la Redaction], Introduction Inositol is a ubiquitous natural product that is abundant in soil. Inositol derivatives are known to occupy key roles in the biology of bacteria, fungi, plants, and animals. It [...]

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Arbutin, a natural glycoside, is well known as a commercial tyrosinase inhibitor, and thus, to prevent pigmentary disorders of skin. In fact, tyrosinase is involved in the biosynthesis of melanin, the skin main pigment. However, arbutin is subject to hydrolysis, which limits its bioactivity. In general, thioglycosides are known to be very resistant to both chemical and enzymatic hydrolysis, which increases the interaction time with their biological targets. A biocatalytic approach allowed us to access to thioglycosidic analogs of arbutin in a green approach with good to excellent yields. Such compounds have then been tested as tyrosinase inhibitors as well as inhibitors of melanin transfer from melanocytes to keratinocytes. This latter mechanism takes place via lectin (or lectin-like) receptors present on the cells surface. p-Aminophenyl β-D-thiogalactopyranoside appears to be an excellent candidate thanks to its tyrosinase inhibitory activity comparable to arbutin, while having the ability to interact with glycan receptors allowing to reduce melanin transfer. [ABSTRACT FROM AUTHOR]

The synthesis of fused bicyclic oxazolidin‐2‐one (OZO) iminosugars was achieved through a tandem Staudinger reduction/retro‐Michael/intramolecular Michael addition from the corresponding OZO azidosugars. Those precursors, based on both aldopentofuranoses and ketofuranohexoses backbones, were obtained following alkylation and oxidation of the related oxazolidine‐2‐thione (OZT) azidosugars. Eight OZO based iminosugars were isolated in good yields and evaluated for their potency as glycosidases inhibitors, thus extending the family of known 1‐Deoxynojirimycin (DNJ) bicyclic analogues. [ABSTRACT FROM AUTHOR]

The crystallographic active site of a thymidylyltransferase from Streptococcus pneumoniae, Cps2L, to engineer the active site of uridylyltransferase and guanidyltransferase. The results obtained from the comparison of active sites of uridylyltransferases and thymidylyltransferases with products bound showed the Q24S variant to provide new pathway to broaden nucleotidylyltransferase activity.

D-Glycopyranosyl glycerols are common natural products and exhibit strong biological properties, notably as moisturizing agents in cosmetics. Their chemical synthesis remains tedious thus decreasing their potential industrial and economic development, as well as the study of their structure-function relationships. In this work, the chemo-enzymatic synthesis of three enantiopure 3-O-(β-D-glycopyranosyl)-sn-glycerols was efficiently performed using an original glycosidase from Dictyoglomus thermophilum and their preservatives properties were assessed using a challenge test method. Amongst them, the 3-O-(β-D-glucopyranosyl)-sn-glycerol exhibited a specific anti-fungus activity. [ABSTRACT FROM AUTHOR]