Spider toxin SNX-482 is a cysteine-rich peptide that interferes with calcium channel activity by binding to voltage-sensing domains of CaV2.3 subtype. Two general binding mechanisms are present in nature: direct binding from the aqueous phase or through lateral diffusion from the membrane, the so-called reduction in dimensionality mechanism. In this work, via coarse-grained and atomistic molecular dynamics simulations, we have systematically studied the spontaneous partitioning of SNX-482 with membranes of different anionic compositions and explored via diffusional analysis both binding mechanisms. Our simulations revealed a conserved protein patch that inserts within the membrane, a preference for binding towards partially negatively charged membranes, and that electrostatics drives membrane binding. Finally, diffusivity calculations showed that the toxin diffusion along the membrane plane is an order of magnitude slower than the aqueous phase suggesting that the critical factor in determin-ing the SNX-482-CaV2.3 binding mechanism is the affinity between the membrane and SNX-482

The Nanosecond Pulsed Electric Field (nsPEF) or Nano Pulsed Stimulation (NPS) is a cutting-edge technology that applies a series of high-voltage electric field pulses of extremely short duration, typically on the order of nanoseconds, to cells. This technique induces the formation of nanopores and activate ionic channels, thereby altering cellular activity. Recent simulations suggest that nsPEF also triggers a novel phenomenon, Protein-mediated Electroporation, whereby pores are formed through the voltage-sensing domain of ionic channels. In this study, we employed Molecular Dynamics simulations and machine learning techniques to investigate the Voltage Sensing Domain (VSD) of a cardiac channel under nsPEF stimulation. Specifically, we characterized VSD structures that form pores helping for the understanding of the physical chemistry underlying the defibrillation effect of nsPEF. Our analysis involved the clustering of 142 replicas simulated for 50 ns under the nsPEF stimulus. Subsequently, we identified the representative structures of each cluster and calculated the free energy between them. Our results demonstrate that although VSD structures are ubiquitous among ionic channels, they exhibit distinct responses to nsPEF stimuli. These findings have significant implications for the development of novel nsPEF-based therapies for cardiac diseases.