Studies of Model Ion Channels in Thick Aligned Multilayers of Phospholipids

摘要

A uniformly aligned multilayer sample of membranes containing peptides has one-dimensional structural order in which the bilayers are the unit cells and preserves the orientational order of peptides relative to the plane of membrane. The goal of this contract was to develop methods to extract these structural information, and to use such methods to study the structural bases of the voltage-gating mechanisms in model channels. During the contract period, we have (1) developed methods of preparing uniformly aligned multilayer samples of membranes containing peptides and proteins; (2) developed the method of oriented circular dichroism, by which we can indeed extract the orientational information of helical peptides in membrane; (3) found that our multilayer samples produce high resolution diffraction data, from which we can obtain the one-dimensional electron density profiles of peptides in bilayer membranes, in particular the position of heavy atomic ions. Keywords: Uniformly aligned multilayers of membranes; X-ray diffraction, Oriented circular dichroism; Alamethicin; Gramicidin. (js)