Quantifying RNA-peptide interaction by single-quantum dot-based nanosensor: an approach for drug screening.

The sequence-specific RRE RNA-Rev binding is essential for HIV-1 replication and provides a useful in vitro system for real-time evaluating the inhibitory effect of drugs on the RRE-Rev interaction. The rapid and sensitive detection of RRE-Rev interaction in complex biological systems represents a fundamental challenge. Here we report the development of a single-quantum-dot (QD)-based nanosensor for sensitively quantifying Rev peptide-RRE interaction and characterizing the potential inhibitors by virtue of single-molecule detection and QD-based fluorescence resonance energy transfer (FRET). We demonstrate that the stoichiometry of Rev peptide binding to RRE can be accurately determined by using this single-QD-based nanosensor. Importantly, this single-QD-based nanosensor can sensitively quantify the inhibitory efficacy of proflavin on the Rev peptide-RRE binding, even in the presence of substantial levels of interference fluorescence from high-concentration proflavin, which usually prevents the discrimination of FRET signals in ensemble measurements. The application of this nanosensor in the screening of libraries of small-molecule drugs will facilitate the development of new drugs against various diseases, cancers, and HIV.