Electrostatic Interaction between ATP and Lysenin Channels Modulates the Conductance
Abstract
This work focuses on understanding the interactions between lysenin, a pore-forming toxin, and ATP.
We measured the conductance of lysenin channels inserted into a planar, lipid bilayer membrane. The channel conductance before and after the addition of ATP was determined from the slope of current versus voltage plots. Single-channel and buffer-exchange experiments were used to assess reversibility and to study the interaction mechanism.
Our results show ATP blocks current through the channels in a concentration dependent manner and induces a significant shift in the voltage required to close the channels. Single channel current measurements indicate the absence of step-wise changes, which suggests ATP binds electrostatically to lysenin and in doing so partially occludes the channels. This hypothesis is further supported by observed reversibility of ATP binding when employing buffer exchange.
The interaction between ATP and lysenin channels induces a decrease in current and shifts the open probability curve upward. The most probable interaction mechanism is electrostatic binding, which may yield partial occlusion of the channels and affect the voltage-gating energy landscape.
Electrostatic Interaction between ATP and Lysenin Channels Modulates the Conductance
This work focuses on understanding the interactions between lysenin, a pore-forming toxin, and ATP.
We measured the conductance of lysenin channels inserted into a planar, lipid bilayer membrane. The channel conductance before and after the addition of ATP was determined from the slope of current versus voltage plots. Single-channel and buffer-exchange experiments were used to assess reversibility and to study the interaction mechanism.
Our results show ATP blocks current through the channels in a concentration dependent manner and induces a significant shift in the voltage required to close the channels. Single channel current measurements indicate the absence of step-wise changes, which suggests ATP binds electrostatically to lysenin and in doing so partially occludes the channels. This hypothesis is further supported by observed reversibility of ATP binding when employing buffer exchange.
The interaction between ATP and lysenin channels induces a decrease in current and shifts the open probability curve upward. The most probable interaction mechanism is electrostatic binding, which may yield partial occlusion of the channels and affect the voltage-gating energy landscape.