Facile Conversion of Aptamers into Sensors Using a 2′-Ribose-Linked Fluorophore

摘要

Nucleic acids can be efficiently selected in vitro to bind diverse small and macromolecular ligands,1 and new methods are being developed with the potential for accelerating the in vitro selection process. To use an in vitro selected nucleic acid, termed an aptamer, as a sensor, the ligand-binding event must be detectable via a useful signal. Approaches for creating ligand-sensitive signaling aptamers include (ⅰ) post-selection modification of an aptamer and (ⅱ) direct selection for a fluorescence-detectable conformational change. Neither approach allows an existing aptamer with useful ligand-binding properties to be directly converted to a signaling device. Ideally, fluorescence-detected signaling aptamers should (ⅰ) function without the use of other reagents or oligonucleotide partners, (ⅱ) be easy to synthesize and, preferably, contain a single fluorescent modification, (ⅲ) report ligand binding using only steady-state measurements, (ⅳ) function directly in realistic biological environments, and (ⅴ) be identifiable via a design strategy that does not require significant pre-existing knowledge about the underlying nucleic acid structure.