Single channel properties of lysenin measured in artificial lipid bilayers and their applications to biomolecule detection.

Single channel currents of lysenin were measured using artificial lipid bilayers formed on a glass micropipette tip. The single channel conductance for KCl, NaCl, CaCl(2), and Trimethylammonium-Cl were 474 ± 87, 537 ± 66, 210 ± 14, and 274 ± 10 pS, respectively, while the permeability ratio P(Na)/P(Cl) was 5.8. By adding poly(deoxy adenine) or poly(L-lysine) to one side of the bilayer, channel currents were influenced when membrane voltages were applied to pass the charged molecules through the channel pores. Current inhibition process was concentration-dependent with applied DNA. As the current fluctuations of α-hemolysin channels is often cited as the detector in a molecular sensor, these results suggest that by monitoring channel current changes, the lysenin channel has possibilities to detect interactions between it and certain biomolecules by its current fluctuations.