Protein recognition via oligonucleotide-linked small molecules: Utilisation of the hemin-binding aptamer

The development of oligonucleotide-linked small molecules for protein recognition is a worthy undertaking with potential applications in drug discovery and diagnostics. Although the ground work for this novel approach to protein recognition is still being laid, a number of promising systems have recently been developed. Herein, we discuss a selection of these systems focusing on the distinct tactics that can be employed for protein binding. Also reported is a new example that underscores the unique versatility of linking aptamers to protein-binding small molecules. In particular, we discuss the development of a chimeric aptamer that in the 'on' state can bind and signal the presence of a target protein. Furthermore, we demonstrate that the activity of this sensing supramolecule can be switched 'off' on cue.