title: Effects of micelle properties on the conformation of oligocholates and importance of rigidity of foldamers.
abstract: The conformation of a cholate hexamer with a clicked tether in between two tricholate units and pyrene groups at the chain ends was studied by fluorescence spectroscopy. In contrast to the parent cholate hexamer that folded in all micelles investigated, the folding of the clicked hexamer was highly dependent on the type of surfactant used to solubilize the compound. The clicked oligocholate folded in the Brij 35 micelle, possibly due to the latter's small size and strong internal hydrophobicity. The oligocholate formed intermolecular aggregates in SDS solutions below the CMC of the surfactant. The aggregates were dissociated by the SDS micelles but the individual oligocholate stayed unfolded. In Triton X-100 and sodium cholate solutions, the aggregated, unfolded, and folded oligocholates coexisted and gradual unfolding occurred with an increasing concentration of the surfactant. The conformation of the clicked oligocholate was sensitive to the nonideal mixing of ionic/nonionic micelles and to the unconventional aggregation of sodium cholate.
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, United States.
authors.forename: Shiyong
authors.initials: S
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D020355:Cholates / Q000737:chemistry*; D008823:Micelles; D008968:Molecular Conformation; D011721:Pyrenes / Q000737:chemistry*; D020358:Sodium Cholate / Q000737:chemistry*; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D020355:Cholates; D008823:Micelles; D011721:Pyrenes; D012996:Solutions; D013501:Surface-Active Agents; C030984:pyrene; D020358:Sodium Cholate