Issue 26, 2012

Hydrogen bond-assisted macrocyclic oligocholate transporters in lipid membranes

Abstract

Three macrocyclic oligocholates containing a carboxyl group, a guanidinium ion, and a Cbz-protected amine, respectively, were studied as membrane transporters for hydrophilic molecules. To permeate glucose across lipid bilayers, the macrocycles stacked over one another to form a transmembrane nanopore, driven by a strong tendency of the water molecules in the internal cavities of the amphiphilic macrocycles to aggregate in a nonpolar environment. To transport larger guests such as carboxyfluorescein (CF), the macrocycles acted as carriers to shuttle the guest across the membrane. Hydrogen-bonds between the side chains of the macrocycles strongly affected the transport properties. Surprisingly, the carboxyl group turned out to be far more effective at assisting the aggregation of the oligocholate macrocycles in the membrane than the much stronger carboxylate–guanidinium salt bridge, likely due to competition from the phosphate groups of the lipids for the guanidinium.

Graphical abstract: Hydrogen bond-assisted macrocyclic oligocholate transporters in lipid membranes

Supplementary files

Article information

Article type
Paper
Submitted
10 Feb 2012
Accepted
30 Apr 2012
First published
01 May 2012

Org. Biomol. Chem., 2012,10, 5077-5083

Hydrogen bond-assisted macrocyclic oligocholate transporters in lipid membranes

L. Widanapathirana, X. Li and Y. Zhao, Org. Biomol. Chem., 2012, 10, 5077 DOI: 10.1039/C2OB25301A

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