An Effective Docking-Guided Strategy for Rational Tailoring of Fluorescent Aptamer Switches of Dimethylindole Red Analogue

The light-up aptamer-dimethylindole red (DIR) complexes have been applied in biochemistry analysis as promising signal transduction tools. However, the unfavorable repulsions between DIR and the long-sequence aptamer switch hinder the complex’s further development, and it is urgent to engineer a feasible and efficient strategy for synchronously and rationally adjusting the DIR chemical structure and the DIR aptamer performance. Herein, we communicate a versatile docking-guided rational tailoring strategy to effectively upgrade a DNA aptamer which specifically turns on the fluorescence of a synthesized amino-functionalized DIR analogue (NH₂-DIR). After optimizing with three-level tailoring strategies including molecule docking-guided tailoring, coarse tailoring, and fine tailoring, the NH₂-DIR aptamer switch with higher binding affinity and specificity, considerable fluorescence-activation ability, and 40% shortened length was obtained. Integrating the experimental and docking results, the binding mechanism between NH₂-DIR and the tailored aptamer was deciphered via three types of interactions.