Mathematical analysis of pore-topore distances in Q I phases Our distance-based analysis strongly suggests that the gyroid is the most likely space group since the normal distances within its nodal approximation are in closest agreement to the expected pore-to-pore distance. Figure shows the consistency of membrane properties with different Q I phase unit cells. The normal distances within the gyroid require the monomers to pack into bilayers that are 3.9 nm to 5 nm thick. The expected pore-to-pore distance from experiment and bilayer simulations is within this range. The Schwarz diamond would require the monomers to pack into bilayers that are 3 nm to 4.2 nm thick. The restricted volume would force unfavorable interdigitation. Furthermore, both the Schwarz diamond and the primitive space groups show large peaks near 8 nm. Attempting to pack a single bilayer with this thickness would likely introduce unstable voids within the bilayer. The small peaks in the gyroid distribution near 8 nm are artifacts of the approximation process of minimal surfaces as distorted bilayers. As the algorithm follows normal vectors of highly curved surfaces, it occasionally misses the first pore-to-pore distance and locates the nearest minimal surface approximately two layers away. On the whole, the evidence clearly supports the gyroid as the geometry most consistent with LLC bilayer thickness and with experiment, and we prioritize simulating the gyroid phase for the remainder of this study.