Light‐Directed Protein Binding of a Biologically Relevant β‐Sheet

Lit-up β attracts α: An azobenzene-ω-amino acid is incorporated as a photoswitch into a β-hairpin motif that mimics the binding site in neuronal NO synthase for α-syntrophin. Light-induced isomerization reversibly converts the stable monomer model peptide from its nonbinding, nonstructured trans form into the β-sheet-forming cis form which shows a remarkable affinity for α-syntrophin.