Target-dependent nucleic acid adapter

摘要

In accordance with the present invention, there is provided a nucleic acid target-dependent adapter linked to a nucleic acid sequence. The adapter comprises linked together a biosensor having a specific sequence complementary to a target sequence of a substrate, the biosensor improving the specificity of the nucleic acid sequence for the substrate, and a blocker stem sequence complementary to a portion of the nucleic acid sequence. In absence of the target sequence of the substrate, the blocker stem sequence forms an intramolecular stem with the nucleic acid sequence linked thereto, preventing exposition of the sequence of the nucleic acid sequence, thus locking the nucleic acid sequence so linked to the adapter in an inactive conformation, and in presence of the target sequence, the blocker stem sequence dissociating from the nucleic acid sequence, thus exposing the nucleic acid sequence linked to the adapter in an active conformation.

主权项

1. A method for turning on or off an enzymatic activity of a nucleic acid molecule having a catalytic core providing an enzymatic activity adapted to be matched to a substrate comprising a target sequence, said method comprising the steps of attaching to said nucleic acid molecule a nucleic acid target dependent switch adapter having a nucleic acid sequence comprising:
i) a blocker stem sequence complementary to a portion of the catalytic core of said nucleic acid molecule; and ii) a biosensor sequence having a sequence complementary to said target sequence, being spaced from the catalytic core by at least three nucleotides and having an affinity level for the target sequence greater than the affinity level of the blocker stem sequence for the catalytic center,wherein in absence of the target sequence of said substrate, said blocker stem sequence forms an intramolecular stem with the catalytic core of said nucleic acid molecule, preventing folding of the catalytic core of the nucleic acid molecule, thus locking said nucleic acid molecule in an inactive conformation, turning off the enzymatic activity and, in presence of said target sequence of said substrate, said biosensor sequence forming conventional Watson-Crick base pairs with said target sequence and said blocker stem sequence dissociating from the intramolecular stem of the catalytic core, thus permitting folding of the catalytic core of the nucleic acid molecule exposing said nucleic acid molecule in an active conformation, turning on the enzymatic activity.