Binding affinity properties of dendritic glycosides based on a beta-cyclodextrin core toward guest molecules and concanavalin A.
The inclusion behavior and concanavalin A binding properties of hepta-antennated and newly synthesized tetradeca-antennated C-6-branched mannopyranosyl and glucopyrannosyl cyclomaltoheptaose (beta-cyclodextrin) derivatives have been evaluated by isothermal titration microcalorimetry and enzyme-linked lectin assay (ELLA), respectively. The synthesis of three first-order dendrimers based on a beta-cyclodextrin core containing 14 1-thio-beta-D-glucose, 1-thio-beta-mannose, and 1-thio-beta-rhamnose residues was performed following a convergent approach and involving (1) preparation of a thiolated bis-branched glycoside building block and (2) attachment of the building block onto heptakis(6-deoxy-6-iodo)-beta-cyclodextrin. Calorimetric titrations performed at 25 degrees C in buffered aqueous solution (pH 7.4) gave the affinity constants and the thermodynamic parameters for the inclusion complex formation of these beta-cyclodextrin derivatives with guests sodium 8-anilino-1-naphthalensulfonate (ANS) and 2-naphthalenesulfonate. The host capability of the persubstituted beta-cyclodextrins decreased with respect to the native beta-CD when sodium 2-naphthalenesulfonate was used as a guest and improved when ANS was used as a guest molecule. Heptavalent mannoclusters based on beta-CD cores enhance the lectin binding affinity due to the cluster effect; however, the increase of the valency from 7 to 14 ligands did not contribute to the improvement of the concanavalin A binding affinity. In addition, the synthesized hyperbranched mannoCDs lost completely the capability as a host molecules.
Ortega-Caballero
F
F
Area de Química Orgánica, Universidad de Almería, 04120 Almería, Spain.
Giménez-Martínez
J J
JJ
García-Fuentes
L
L
Ortiz-Salmerón
E
E
Santoyo-González
F
F
Vargas-Berenguel
A
A
D002151:Calorimetry; D002240:Carbohydrate Sequence; D003208:Concanavalin A / Q000378:metabolism*; D003505:Cyclodextrins / Q000737:chemistry* / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006027:Glycosides / Q000737:chemistry* / Q000378:metabolism*; D037102:Lectins / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011952:Receptors, Concanavalin A / Q000378:metabolism; D047392:beta-Cyclodextrins
D003505:Cyclodextrins; D006027:Glycosides; D037102:Lectins; D011952:Receptors, Concanavalin A; D047392:beta-Cyclodextrins; D003208:Concanavalin A; C031215:betadex