ABSTRACT

Understanding the functional mechanisms of any biological macromolecule requires the atomic resolution characterization of both its three-dimensional structure and the nature of its conformational changes. While the elucidation of both can be performed for many cytosolic macromolecules, difficulties associated with the application of physical methods to biological membranes still limit our understanding of integral membrane proteins. Fourier transform infrared (FT-IR) spectroscopy is one physical method that is readily applicable to membrane systems. The technique provides information on the frequencies of molecular vibrations, which are exquisitely sensitive to local environment and covalent structure. In particular, FT-IR spectra are very sensitive to the subtle structural alterations that occur in individual residues upon protein conformational change.