RNA aptamers that reversibly bind to photoresponsive peptide.

Modulation of biological network constituted by diverse interactions among biologically active molecules has provided innovative biotechnologies. Here, we report RNA aptamers that bind to photoresponsive peptide (KRAzR; Lys-Arg-Azobenzene-Arg) containing azobenzene chromophore, which can change its geometrical structure by phohtoirradiation. Aptamers were identified by 10 cycles of in vitro selection procedure from DNA library containing 70 nt random region. Surface plasmon resonance (SPR) analysis demonstrated that interactions between aptamers and KRAzR were fully controlled by appropriate photoirradiation. Upon irradiation of 360 nm light over the KRAzR-immobilized surface, the binding of each aptamer to the surface was significantly decreased. Subsequent photoirradiation of the same surface with 430 nm light restored the aptamer binding ability of the surface. We also observed that direct photoirradiation of aptamer-peptide complex on a gold surface actively promoted dissociation of the complex.