Conformational changes of an oriented film of photosensitive proteins observed by polarized ATR infrared spectroscopy

We apply polarized Attenuated Total Reflection Fourier Transform Infrared spectroscopy (ATR-FTIR) to study conformational changes of the prototype photosensitive protein bacteriorhodopsin (BR). The experiments are performed on hundreds-nanometer-thick films of stacked membrane patches embedding BR molecules. Moreover, we report our results on functionalization of silicon surfaces that are preliminary to further experiments involving faced-down silicon substrates on ATR crystal in order to increase the sensitivity down to very thin protein films.