Photocontrol of Peptide Self-Assembly and Catalytic Activity

Coiled-coil peptides can be designed to self-assemble with high affinity and selectivity, leading to them being widely employed for the de novo design of synthetic biomaterials. Active control of coiled-coil peptide formation allows spatiotemporal control of their binding interactions, a property which has proven useful in synthetic materials and biological applications. Previous studies showed the ability of the hydrophobic core to adapt to different amino acids with different sizes and polarities. In particular, the use of light to reversibly control peptide structure has been investigated because of the high resolution and biocompatibility of this strategy. Previous efforts to reversibly photocontrol coiled-coil peptides relied on intramolecular cyclization to control peptide structure, or the intermolecular connection of two separate coiled coil strands with a photoswitchable linker. The incorporation of photoswitches in the binding interface of coiled coils has not yet been attempted, and provide a more direct route for control over their activity. Therefore the incorporation of photoswitchable azobenzene-based amino acids, which change structure and polarity through cis/trans isomerization, allow for photocontrol over coiled-coil assembly.<br/><br/>In a second example, we incorporated phenylazo-phenylalanine in betasheet formning peptides to obtain photocontrol in the mode of assembly. With the azobenzene units in a trans-form, betasheets were obtained while upon irradiation these were transformed in micellar structures. Introduction of histidines in the peptide design resulted in catalytic active betasheets, which could be reversibly switched upon irradiation of the azobenzen units. Both examples show that the introduction of azobenzene-derived amino acids in peptides yields photocontrol over the assembly and catalytic activity in various supramolecular assemblies.