Photoswitchable Unsymmetrical Ligand for DNA Hetero‐Mismatches

Photoswitchable DNA‐binding ligands should be useful for controlling diverse biological functions involving DNA and reversible assembly of DNA‐based nanostructures. In work directed towards the development of photoswitchable ligands with various sequence specificities, we have elaborated an efficient synthesis of photoswitchable unsymmetrical ligands possessing pairs of different base recognition elements. A novel photoswitchable ligand incorporating an acylated aminonaphthyridine and an azaquinolone as its base recognition elements can bind to the CAG/CAG sequence in response to light stimuli.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) We have established an efficient synthetic route for photoswitchable DNA‐binding ligands incorporating two different base‐recognition elements. A novel photoswitchable DNA‐binding ligand, NCAA (naphthyridine‐carbamate‐azaquinolone‐functionalized azobenzene), recognizes DNA duplexes containing a CAG/CAG sequence, and the binding is reversibly controlled by external light stimuli.