It is important to note that structural refinement seemed to rule out the possibility for AzTG-4 to adopt the AzTG-6 binding mode and vice versa: placement of the AzTG-4 photoswitch in the AzTG-6 photoswitch pocket and placement of the AzTG-6 photoswitch in the AzTG-4 photoswitch pocket were discounted by the electron densities, which indicates that the AzTG-4 and AzTG-6 azobenzene moieties do indeed exhibit different binding modes. This can be directly attributed to the 2-carbon difference in their linker length (the only difference existing between the two derivatives); the shorter linker of AzTG-4 prevents its azobenzene group from accessing the phospholipid-binding region situated between the M1, M3, and M4 helices where the terminal group of AzTG-6 (and other O-8 TG derivatives) resides.