title: Molecular recognition thermodynamics of bile salts by beta-cyclodextrin dimers: Factors governing the cooperative binding of cyclodextrin dimers.
abstract: The complex stability constants (K(S)), standard molar enthalpy (DeltaH degrees), and entropy changes (DeltaS degrees) for the inclusion complexation of two families of beta-cyclodextrin (beta-CD) dimers, i.e. beta-CD dimers Se1-Se4 bearing 2,2'-diselenobis(benzoyl) tether (Se-dimers) and beta-CD dimers Py1-Py4 bearing 2,2'-bipyridine-4,4'-dicarboxy tether (Py-dimers), with four bile salt guests, i.e. sodium cholate (CA), sodium deoxycholate (DCA), sodium glycocholate (GCA), and sodium taurocholate (TCA), were determined at 25 degrees C in Tris buffer solution (pH 7.4) at 298.15 K by means of isothermal titration microcalorimetry. The thermodynamic parameters obtained, together with the ROESY spectra of interactions between beta-CD dimers and bile salts, consistently suggest that the length, flexibility, and structure of spacers linking the two beta-CD cavities not only determine the binding modes but also significantly alter the molecular selectivity of beta-CD dimers.
authors.affiliation: Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, People's Republic of China. yuliu@public.tpt.tj.cn
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.forename: Lu
authors.initials: L
authors.lastname: Yu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Fan
authors.forename: Fei
authors.initials: F
authors.lastname: Ding
mesh_terms: D002151:Calorimetry; D019281:Dimerization; D009682:Magnetic Resonance Spectroscopy; D013816:Thermodynamics; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D047392:beta-Cyclodextrins; C031215:betadex