ABSTRACT
Infrared (IR) spectroscopy has long been recognized as a potentially useful method to gain information on the structure of molecules of biological interest. This chapter provides the overview of the IR spectroscopy possibilities to determine protein and other membrane components conformation and orientation in membranes. A multilayer assembly is obtained by transferring a monolayer spread at the air-water interface by a cycle of dipping and withdrawal of the supporting plate through the monolayer. When the orientation of various molecular axes is measured with respect to a normal to the plate supporting the membrane by dichroism measurements, it is required that the membranes themselves orient parallel to the supporting plate. Orientation of various chemical bonds or chemical groups can then be determined by studying the polarization of their specific absorption bands. Orientational parameters would be useful at the level of the computation of the association of the membrane molecules in monolayers.
