Ion trajectories for mixed-cationic simulations with Na ⁺ and K ⁺ from the previously published dataset ( Saponaro et al., 2021a ). (A–D) Simulations were conducted in 900 mM Na⁺ at −500 mV (A and B) as well as 900 mM mixed Na⁺/K⁺ (1:1) at (C) −500 mV and (D) −700 mV.