Issue 16, 2014

Fructose controlled ionophoric activity of a cholate–boronic acid

Abstract

Wulff-type boronic acids have been shown to act as ionophores at pH 8.2 by transporting Na+ through phospholipid bilayers. A cholate–boronic acid conjugate was synthesised and shown to be an ionophore, although the hydroxyl-lined face of the cholate moiety did not enhance ion transport. Mechanistic studies suggested a carrier mechanism for Na+ transport. The addition of fructose (>5 mM) strongly inhibited ionophoric activity of the cholate–boronic acid conjugate, mirrored by a strong decrease in the ability of this compound to partition into an organic phase. Modelling of the partitioning and ion transport data, using a fructose/boronic acid binding constant measured at pH 8.2, showed a good correlation with the extent of fructose/boronic acid complexation and suggested high polarity fructose/boronic acid complexes are poor ionophores. The sensitivity of ion transport to fructose implies that boronic acid-based antibiotic ionophores with activity modulated by polysaccharides in the surrounding environment may be accessible.

Graphical abstract: Fructose controlled ionophoric activity of a cholate–boronic acid

Supplementary files

Article information

Article type
Paper
Submitted
21 Jan 2014
Accepted
27 Feb 2014
First published
27 Feb 2014
This article is Open Access
Creative Commons BY license

Org. Biomol. Chem., 2014,12, 2576-2583

Author version available

Fructose controlled ionophoric activity of a cholate–boronic acid

J. R. D. Brown, I. C. Pintre and S. J. Webb, Org. Biomol. Chem., 2014, 12, 2576 DOI: 10.1039/C4OB00165F

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