Molecular Anatomy of an Ion Channel Explored Utilizing Fluorescence Spectroscopy

Abstract

Ion channels are transmembrane proteins and represent important cellular components that connect the inside of the cell to its outside in a selective fashion. The linear ion channel peptide gramicidin serves as an excellent prototype for monitoring the organization, dynamics and function of membrane-spanning channels due to a variety of reasons. The fluorescent tryptophan residues in gramicidin channels are crucial for establishing and maintaining the structure and function of the channel in the membrane bilayer. In this review, we have highlighted a variety of representative fluorescence-based approaches to gain molecular insight into gramicidin conformations. Since gramicidin shares common structural features with more complex ion channels, the results from fluorescence-based studies with gramicidin could be relevant for more complex ion channels.