Photoswitchable 2-Phenyldiazenyl-Purines And Their Influence On Dna Hybridization

Recently, photochromic derivatives of nucleobases have drawn attention for regulating oligonucleotide hybridization with light for photopharmacological applications. The nucleobase moiety provides attractive interaction for hybridization, whereas the photochromic moiety can alter the interaction upon irradiation due to conformational changes. Herein we report the synthesis of 2-phenyldiazenyl-substituted 2'-deoxyadenosine (dA(Azo)) and 2'-deoxyguanosine (dG(Azo)) and investigate their influence in a DNA context by UV/Vis absorption, fluorescence and CD spectroscopies. For comparison, the literature-known azobenzeneC-nucleosideDNAzowas used as a reference system. It could be shown that photochromic purines improve overall hybridization affinity compared to azobenzeneC-nucleosides. In particular, 2'-deoxyadenosine analogue dA(Azo)increases melting temperatures by 7.5 degrees C in the favoredtrans state with 86 % of the switching efficiency of the reference system.