The FG-FG distance frequencies are plotted as a histogram with three colour coding, representing the relative positions of the functional groups with respect to the pore, as shown in Figure . The orientation of the linker puts the functional group into two distinct positions, either pointing inside, "In" or outside, "Out" of the pore of interest. As the "In-In" pair is of most relevance to a molecule binding inside the pore, we have separated and labelled each distance with different colours.