A way to overcome these ambiguities and dynamically measure effective pore size is via analysis of pore area explored by translocating particles. Thus, to characterize the pore, we use PoreBlazer to estimate the pore size distribution (PSD) within the atomistic simulation. The pore size is estimated by a geometric approach, where spheres with the largest possible diameter without overlapping the atomic structure of the membrane are identified. The PSD is calculated over the final 200 ns of simulation. The PSDs for the glycerol-solvated and watersolvated gyroid structures are shown in Fig 8 . The pores formed solely by the LLC monomer exist with diameters primarily in the range 0.3 nm to 0.5 nm, but the diameter exists up to 0.75 nm. This range is somewhat low in comparison with the rejection data seen experimentally. Sucrose, which has a hydrodynamic diameter of 0.94 nm, was almost rejected completely with rejection percentage 97 ± 1%. Glucose, which has a hydrodynamic diameter of 0.73 nm, was rejected with rejection percentage 87 ± 4%. Solutes with diameters within the range 0.3 nm to 0.5 nm were partially rejected with rejection percentages less than 50%. However, the spread of the pore size distribution indicates that the pore boundaries are not perfectly uniform, which is consistent with the minimal surface distribution functions. We observe ill-defined pores where the uniform, annular regions are not defined by a split between LLCs and solvent, as indicated by the penetration of head groups into the pore region (see Fig 6). Rather, they are defined as a hydrophobic-hydrophilic cutoff, and accordingly, we report PSDs for both the LLC-solvent split and the hydrophobic-hydrophilic split in Fig 8, with the hydrophilic volume diameter often being as large as 0.8-1.2 nm. We conclude that the true effective pores experienced by solutes during operation are likely between these two extremes. Head groups can impede solutes