Fig. 3: Characterization of open-pore current rectification using a wide library of aerolysin mutants.

a, Left: sketches of aerolysin wt and mutant E258Q showing the deletion of a charged residue; positive charges are drawn in blue and negative charges are drawn in pink. Right: ion radial probability distributions (blue for K⁺, red for Cl⁻) measured on the MD simulations of aerolysin wt and mutant K238A–K242A at −200 mV. b, Open-pore IV curves of several mutants of aerolysin showcasing the different degrees of rectification tuned by the lumen charge (1 M KCl, 10 mM phosphate pH 6.2, 1 Hz). c, Left: schematic representation of mutant E258Q in the rectification model. The deletion of E258 that is negatively charged is represented as the addition of a fixed positive charge in the pore’s energy landscape, leading to ion accumulation downstream of the fixed charge. E, electric field. Right: rectification factor β as a function of the sign and position of the charge deleted after mutation. Solid curve: theoretical model (Supplementary equation (2)).