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Article
Oligomeric Cholates: Amphiphilic Foldamers with Nanometer-Sized Hydrophilic Cavities
Journal of the American Chemical Society
  • Yan Zhao, Iowa State University
  • Zhenqi Zhong, Iowa State University
Document Type
Article
Disciplines
Publication Version
Published Version
Publication Date
11-1-2005
DOI
10.1021/ja056151p
Abstract

The hydroxyl at the C-3 of cholic acid was converted to an amino group, and the resulting amino-functionalized cholic acid was used as a monomer to prepare amide-linked oligomeric cholates. These cholate oligomers fold into helical structures with nanometer-sized hydrophilic internal cavities in solvent mixtures consisting of mostly nonpolar solvents such as carbon tetrachloride or ethyl acetate/hexane and 2−5% of a polar solvent such as methanol or DMSO. The conformations of the foldamers were studied by UV, fluorescence, fluorescence quenching, and fluorescence resonance energy transfer. The nature of the polar/nonpolar solvents and their miscibility strongly influenced the folding reaction. Folding was cooperative, as evidenced by the sigmoidal curves in solvent denaturation experiments. The folded conformers became more stable with an increase in the chain length. The folding/unfolding equilibrium was highly sensitive toward the amount of polar solvent. One percent variation in the solvent composition could change the folding free energies by 0.5−1.4 kcal/mol.

Comments

Reprinted (adapted) with permission from Journal of the American Chemical Society 127 (2005): 17894, doi:10.1021/ja056151p. Copyright 2005 American Chemical Society.

Copyright Owner
American Chemical Society
Language
en
File Format
application/pdf
Citation Information
Yan Zhao and Zhenqi Zhong. "Oligomeric Cholates: Amphiphilic Foldamers with Nanometer-Sized Hydrophilic Cavities" Journal of the American Chemical Society Vol. 127 Iss. 50 (2005) p. 17894 - 17901
Available at: http://works.bepress.com/yan_zhao/35/