Effects of Lipid Asymmetry and Sphingomyelin Isoforms on Actinoporin Pore Formation Probed by SAXS

This proposal aims to investigate the role of sphingomyelin in regulating the activity of the actinoporin Fav, a pore-forming toxin that binds selectively to sphingomyelin-containing membranes, though the influence of lipid distribution and acyl chain composition on pore formation remains unclear. To address this, we will examine the effect of sphingomyelin asymmetry by preparing synthetic vesicles with controlled leaflet distribution and evaluate how sphingomyelin acyl chain length affects membrane binding, insertion, and pore formation. Structural and dynamical information on lipid organization, protein binding, and conformational changes will be obtained by combining SAXS with biochemical assays and molecular dynamics simulations. Together, these studies will clarify how sphingomyelin distribution and acyl chain length modulate actinoporin function.