High resolution studies of lipid bilayers High resolution studies of lipid bilayers Robert M. Suter, Ruitian Zhang, Wenjun Sun, Stephanie Tristram-Nagle, and John F. Nagle Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213 Fluctuations are vital to biological systems. Average structures, which specify the baseline about which fluctuations occur, are also important. We have found, in studying biomembranes, that taking account of fluctuations in the analysis of data can be an important part for correctly determining average structure. Therefore, there are two important reasons to study fluctuations. Each layer contains a bilayer membrane made of a single type of lipid molecule and a water layer which separates successive membranes.
Vesicles are of the order of one micron in diameter.
Biomembranes are usually quite fluid. In the biologically relevant La or fluid phase, the hydrocarbon chains of the lipid molecule are disordered and there is only short range order in the intermolecular packing. One observes the well known broad, liquid-like peak in the wide angle region. Since 2qhh in degrees, these peaks are well separated. The heights of the peaks have been normalized to facilitate comparison of peak shapes.