MOLECULAR DESIGN OF PHOTO-MODULATED ION C HANNELS BASED ON GRAMICIDIN-A AND THEIR ELECTROCHEMICAL PROPERTIES

A new photoisomeriozable analogue of gramicidin A (photo-GA) was synth esized by covalent coupling of two gramicidin A monomers with 4,4'-bis (succinylglycylamidyl)azobenzen. The conductance of the bilayer lipid membrane (BLM) was studied in the presence of the photo-GA. Irradiatio ns of dark- or light-adapted BLM containing photo-GA induced transitio ns between the stationary levels of integral membrane currents so that dark current (I(d)), UV-photocurrent (I(uv)) and visible light photoc urrent (I(vis)) were observed (I(d) < I(vis) < I(uv)). The single chan nel conductivity was 2.4 +/- 0.2 pS in 100 mM KCl at room temperature. It has been concluded that the electrochemical characteristics of lig ht-sensitive channels can be modulated by structural changes in the ph otolinker mojety, which provides new prospects in designing photobiose nsors suitable for recording, storage and processing optical informati on.