Ref HAL: hal-00821002_v1
DOI: 10.1007/s00706-012-0881-7
Résumé: The development of synthetic systems displaying dynamic and adaptive characteristics is a formidable challenge with wide applications from biotechnology to therapeutics. Recently, we described a dynamic and programmable nucleic acid-based system relying on the formation of reversible boronate internucleosidic linkages. The DNA- or RNA-templated system comprises a 50 -ended boronic acid probe connecting a 30 -ended ribonucleosidic oligonucleotide partner. To explore the dominant factors that control the reversible linkage, we synthesized a series of 30 -end modified ribonucleotidic strands. Evidence suggests that geometric and steric factors are key features for controlling the equilibria.

Ref HAL: hal-00805661_v1
DOI: 10.1039/c3ra23115a
Résumé: The compatibility of metallic catalysts derived from plants was studied for the chemical solid-phase synthesis of a high added-value biomolecule: 59-capped RNA (GpppRNA or 7mGpppRNA) involved in many essential biological processes. These molecules are of great interest for biologists for structural and mechanistic studies of their complexes with RNA capping enzymes. Several polymetallic catalysts were prepared from various metallophytes species growing in mine sites in a context of phytoremediation programs. Their catalytic efficacy was evaluated for the coupling reaction of guanosine diphosphate (GDP) with a preactivated 5'-monophosphate hexathymidylate (pT6) or a pRNA to form 5'-GpppT6 or 5'-GpppRNA respectively. The direct coupling of 7mGDP with pRNA was also investigated. With Znenriched catalysts obtained from Zn metallophytes, the capping yields were better than those obtained with conventional catalyst ZnCl2. Interestingly with Ni-enriched plant extracts the yield was higher than with NiCl2, a polymetallic catalysis was certainly involved. With this plant-inspired catalysis, metallophytes wastes become efficient and greener polymetallic catalysts. Finally, environmental benefits and effectiveness can be combined.

Ref HAL: hal-00788061_v1
DOI: 10.1002/ejoc.201201311
Résumé: Monoconjugated and multiply conjugated oligonucleotides were efficiently synthesized by starting from monothiohexyl- or tetra-thiohexyl-oligonucleotides and treatment with acrylamide derivatives (carbohydrates, ferrocene, biotin, fluorescent dyes, deoxycholic acid). The thiol Michaeltype additions (TMTAs) occurred during the deprotection and release of the oligonucleotides from the solid support, so no additional time for conjugation was needed. Sequential combination either of Copper-catalyzed Azide-Alkyne Cycloaddition (CuAAC) on solid support and then TMTA or of TMTA followed by CuAAC in solution allowed the synthesis of several oligonucleotides decorated with two different biomolecules.

Ref HAL: hal-00788052_v1
DOI: 10.1016/J.BIOS.2012.07.003
Résumé: Nowadays, there is a great interest for understanding the structure/function relationship governing recognition of carbohydrates by their receptors for the design of new treatments. Indeed, carbohydrates and glycoconjugates play a major role in key biological events such as cell-cell recognition, pathogenesis inflammation, and host pathogen interactions. Pseudomonas aeruginosa (PA) is one of the predominant bacterium encountered in nosocomial infections. PA infections often lead to chronic inflammation and eventually to death despite aggressive antibiotic therapy: the emergence of resistant strains and biofilm formation seems to give a selective advantage to the bacterium. A promising approach is to inhibit the virulence factors of PA such as PA-IL which is a galactose specific lectin. Herein, we develop a microarray to probe the binding of six galacto-conjugates to PA-IL differing by their spatial configuration and geometry. This microsystem is made of 40 independent microwells in which 64 spots of glycoconjugates probes are arrayed by using DNA Directed Immobilization (DDI). This microsystem allows, in a multiplex fashion, qualitative information on the binding by direct fluorescence readout as well as quantitative information by the determination of IC50 values in a competition assay and surface dissociation constants (Kd). According to our data, direct fluorescent signals (FI635), IC50 and Kd values provided similar ranking for glycoconjugates with respect to PA-IL binding thus affording a general tool for the selection of galacto-conjugates displaying the best affinities toward PA-IL.

Ref HAL: hal-00816545_v1
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