posted on 2013-11-19, 00:00authored byFeng Li, Yanwen Lin, X. Chris Le
DNA
three-way junctions (DNA TWJs) are important building blocks
to construct DNA architectures and dynamic assemblies. We describe
here a binding-induced DNA TWJ strategy that is able to convert protein
bindings to the formation of DNA TWJ. The binding-induced DNA TWJ
makes use of two DNA motifs each conjugated to an affinity ligand.
The binding of two affinity ligands to the target molecule triggers
assembly of the DNA motifs and initiates the subsequent DNA strand
displacement, resulting in a binding-induced TWJ. Real-time fluorescence
monitoring of the binding-induced TWJ enables detection of the specific
protein targets. A detection limit of 2.8 ng/mL was achieved for prostate-specific
antigen. The binding-induced TWJ approach compares favorably with
the toehold-mediated DNA strand-displacement, the associative (combinative)
toehold-mediated DNA strand-displacement, and the binding-induced
DNA strand-displacement. Importantly, the binding-induced TWJ broadens
the scope of dynamic DNA assemblies and provides a new strategy to
design protein-responsive DNA devices and assemblies.