A model for the hysteresis observed in gating of lysenin channels

- Lysenin channels exhibit both dynamic and static hysteresis elements.
- Static hysteresis arises from the collection of free charge on a polarized BLM.
- Experimental data supports model as a shift in I-V curve.
- Temperature dependent hysteresis also supports mechanism suggested by model.

The pore-forming toxin lysenin self-inserts to form conductance channels in natural and artificial lipid membranes containing sphingomyelin. The inserted channels exhibit voltage regulation and hysteresis of the macroscopic current during the application of positive periodic voltage stimuli. We explored the bi-stable behavior of lysenin channels and present a theoretical approach for the mechanism of the hysteresis to explain its static and dynamic components. This investigation develops a model to incorporate the role of charge accumulation on the bilayer lipid membrane in influencing the channel conduction state. Our model is supported by experimental results and also provides insight into the temperature dependence of lysenin channel hysteresis. Through this work we gain perspective into the mechanism of how the response of a channel protein is determined by previous stimuli.