25] Fourier transform infrared studies of an active proton transport pump

Abstract

Publisher Summary This chapter describes the recent progress in the field of infrared spectroscopy, which has made it possible to probe small changes occurring in biomembranes. Fourier transform infrared (FTIR) spectroscopy that provides significantly increased spectral sensitivity and resolution as compared to conventional scanning infrared systems has facilitated the detection of vibrations arising from single groups in a complex macromolecular system. In addition, the use of powerful computers has led to the introduction of improved methods for data analysis, such as Fourier self-deconvolution. The chapter illustrates some of the through which FTIR spectroscopy can be used to probe specific membrane components involved in active proton transport. In regard to proton transport through biomembranes, FTIR spectroscopy provides a means of detecting the groups that are directly involved in proton transport and energy transduction. The chapter focuses on bacteriorhodopsin (bR), the light-driven proton pump found in the purple membrane of Halobacteria halobium . FTIR measurements have led to identification of specific protein and chromophore groups that participate in different steps of the bR photocycle.