Design,Synthesis and Characterization of a Allosteric Receptor based on Beta-Cyclodextrin

QUIROLO ZULMA BEATRIZ; MARTINS JOSE; JOSE L. MASCARENAS; VERONICA DODERO

Bath

Encuentro; RSC Macrocyclic and Supramolecular Chemistry Meeting; 2011

Beta-Cyclodextrin (Beta-CyD) is a macrocyclic oligosugar composed of seven D- glucopyranose units linked by á-1,4 bonds. The glucopyranose ring contains secondary hydroxyl groups at 2- and 3- positions and primary hydroxyl groups at the 6- positions. The whole molecule assumes a rigid structure because of the formation of a belt of intramolecular hydrogen bonds between hydroxyl groups at the 2- and 3-positions of adjacent glucose units. The presence of the hydroxyl groups makes the upper and lower end of the molecule hydrophilic. The cavity of cyclodextrins is rendered hydrophobic because of the presence of glycosidic oxygen and C-H units1.These features convert them in very interesting moieties with inclusion capacities of diverse molecules with differentiated affinities depending on the type and position of their modifications. Meanwhile with the best substrates, a well-fitting cyclodextrin can achieve a binding constant, in water, of ca. 104 M-1; this is not as strong as some enzymes and most antibodies, which typically bind several substrate segments. Incorporation of a second Beta-CyD forming a dimer2 has been reported that strong increase its binding capability with model substrates (106- 1011 M-1).