Using dual exonucleases to finely distinguish structural adjustment of aptamers for small-molecule detection.

ABSTRACT: The binding of small molecules to their DNA aptamers can modulate their susceptibility to digestion by exonucleases, however, absolute differentiation between digestion and inhibition has never been reported. Here, we show that the digestion of aptamers by T7 exonuclease can be completely inhibited upon binding of small-molecule targets and exploit this finding for the first time to achieve sensitive, label-free small-molecule detection. We use a quinine-binding aptamer to show that target binding entirely halts T7 exonuclease digestion, leaving behind an intact double-stranded product that retains strong target affinity. On the contrary, digestion of nontarget-bound aptamer produces a single-stranded product incapable of target binding. Exonuclease I efficiently eliminates these single-st

SUBMITTER: Wang L 

PROVIDER: S-EPMC9042303 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature