| Abstrakt: |
Using the planar lipid bilayer technique, the dependence of properties of ion channels formed by syringomycin E on bath ion composition (electrolyte concentration and pH) and on the applied potential was studied. Time courses of the membrane current in field reversal experiments with 1M NaCl, pH 6 in the bathing solution were similar to the time courses observed with a bathing solution of 0.1 M NaCl, pH 2: there was no increase (decrease) of the membrane current at positive (negative) values of the transmembrane potential. However, kinetic curves were different at 0.1 M. NaCl, pH 6 and pH 9. At pH 6 there was an abrupt increase (decrease) of the membrane current over the time at the positive (negative) values of the applied potential. At pH 9 there was a reversed current response. The results indicate that charged groups are likely to be responsible for opening or closing the channel facing the water phase. Based on these data, a model is proposed describing the potential dependent opening and closing of ion channels formed by syringomycin E. |
