Detecting a tag on a channel opening: blockage of the biotinylated channels by streptavidin

C-terminal biotinylated alamethicin and gramicidin A were prepared by a combination of the Fmoc-solid-phase peptide synthesis and the solution method. The ion-channel current of these peptides was dramatically suppressed by the addition of streptavidin, suggesting the potential of this approach for the elucidation of channel protein structure and for the design of artificial sensors and receptors.