Conformational photoswitching of a synthetic peptide foldamer bound within a phospholipid bilayer

The dynamic properties of foldamers, synthetic molecules that mimic folded biomolecules, have mainly been explored in free solution. Here we report on the design, synthesis, and conformational behavior of photoresponsive foldamers bound in a phospholipid bilayer akin to a biological membrane phase. These molecules contain a chromophore, which can be switched between two configurations by different wavelengths of light, attached to a helical oligoamide that both promotes membrane insertion and communicates conformational change along its length. Light-induced structural changes in the chromophore are translated into global conformational changes, detected by monitoring the solid state ¹⁹F nuclear magnetic resonance signals of a remote fluorine-containing residue located 1 to 2 nm away. The behavior of the foldamers in the membrane phase is similar to that of analogous compounds in organic solvents.