The 2-carbon difference in length between the AzTG-4 and AzTG-6 linkers was sufficient to restrain the AzTG-4 azobenzene group and limit its occupation to a more superficial cavity within the TM domain (Figure ). In the case of AzTG-2, its short linker would further restrain the azobenzene group, potentially resulting in suboptimal placement within the AzTG-4 azobenzene hydrophobic pocket. For example, with AzTG-4, the photoswitch is situated such that the azobenzene lies between Leu253 and Leu249. With AzTG-2 however, the azobenzene group would shift towards the surface, orienting the distal phenyl group to potentially clash with the two aforementioned sidechains and increasing steric hindrance.