ASYMMETRICAL LIPID CHARGE CHANGES THE SUBCONDUCTING STATE OF THE POTASSIUM CHANNEL FROM SARCOPLASMIC-RETICULUM

The K+ channel of sarcoplasmic reticulum was incorporated into planar lipid bilayers having various net surface charges. The conductance of both the main-state and substate increased with the increase in negative charges of the membrane and vice verse. The change in the conductance of the substate was larger than that of the main-state. The K+ channel reconstituted into asymmetrical planar lipid bilayers revealed that the effect on the substate was derived from only one half (trans) of the bilayer. The substate of the K+ channel may assume a conformation in which part of the channel located at the trans side is susceptible to some changes induced by the trans surface charge. (C) 1994 Academic Press, Inc.