ja306596m_si_002.pdf (24.13 MB)
Mechanism of Ion Transport by Fluorescent Oligoester Channels
journal contribution
posted on 2012-09-26, 00:00 authored by Joanne
M. Moszynski, Thomas M. FylesThe synthesis and membrane activity of a suite of linear
oligoesters
containing a common diphenylacetylene unit core and differing in the
hydroxyl terminus are reported. Active compounds formed high-conductance
channels efficiently in both vesicle and planar bilayers, with one
compound showing a very unusual slow loss of transport activity over
a 20–30 min period. Steady-state and time-resolved fluorescence
studies establish the rapid partition of active compounds to the bilayer
and identify at least three types of membrane-associated species by
their differing fluorescence lifetimes. The change in the distribution
of species is correlated with the slow loss of activity. The results
are interpreted in terms of an aggregate within a single bilayer leaflet
that is nonetheless competent to transport ionic species through the
bilayer. The properties of such structures, revealed by these compounds,
appear to be consistent with commonly observed behaviors of other
synthetic ion channels.