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Article
Effects of Amphiphile Topology on the Aggregation of Oligocholates in Lipid Membranes: Macrocyclic versus Linear Amphiphiles
Langmuir
  • Lakmini Sandachaya Widanapathirana, Iowa State University
  • Yan Zhao, Iowa State University
Document Type
Article
Disciplines
Publication Version
Published Version
Publication Date
5-1-2012
DOI
10.1021/la301090t
Abstract
A macrocyclic and a linear trimer of a facially amphiphilic cholate building block were labeled with a fluorescent dansyl group. The environmentally sensitive fluorophore enabled the aggregation of the two oligocholates in lipid membranes to be studied by fluorescence spectroscopy. Concentration-dependent emission wavelength and intensity revealed a higher concentration of water for the cyclic compound. Both compounds were shown by the red-edge excitation shift (REES) to be located near the membrane/water interface at low concentrations, but the cyclic trimer was better able to migrate into the hydrophobic core of the membrane than the linear trimer. Fluorescent quenching by a water-soluble (NaI) and a lipid-soluble (TEMPO) quencher indicated that the cyclic trimer penetrated into the hydrophobic region of the membrane more readily than the linear trimer, which preferred to stay close to the membrane surface. The fluorescent data corroborated with the previous leakage assays that suggested the stacking of the macrocyclic cholate trimer into transmembrane nanopores, driven by the strong associative interactions of water molecules inside the macrocycles in a nonpolar environment.
Comments

Reprinted (adapted) with permission from Langmuir 28 (2012): 8165, doi:10.1021/la301090t. Copyright 2012 American Chemical Society.

Copyright Owner
American Chemical Society
Language
en
File Format
application/pdf
Citation Information
Lakmini Sandachaya Widanapathirana and Yan Zhao. "Effects of Amphiphile Topology on the Aggregation of Oligocholates in Lipid Membranes: Macrocyclic versus Linear Amphiphiles" Langmuir Vol. 28 Iss. 21 (2012) p. 8165 - 8173
Available at: http://works.bepress.com/yan_zhao/25/