Bifunctional colorimetric oligonucleotide probe based on a G-quadruplex DNAzyme molecular beacon

Anal Chem. 2011 Dec 1;83(23):8871-6. doi: 10.1021/ac2006763. Epub 2011 Nov 3.

Abstract

A label-free bifunctional colorimetric oligonucleotide probe for DNA and protein detection has been developed on the basis of a novel catalytic molecular beacon consisting of two hairpin structures and a split G-quadruplex DNAzyme in the middle. The two loops of this molecular beacon consist of thrombin aptamer sequence and the complementary sequence of target DNA, which are utilized to sense single-stranded DNA and thrombin. The G-quadruplex DNAzyme can effectively catalyze the H(2)O(2)-mediated oxidation of 3,3',5,5'-tetramethylbenzidine sulfate to generate colorimetric signal. Upon addition of the target, the DNA or protein combines with one loop of the hairpin structures, and meanwhile drives the middle G-quadruplex DNAzyme to dissociate. This results in a decrease of catalytic activity, enabling the separate analysis of DNA and thrombin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Benzidines / chemistry
  • Catalysis
  • Colorimetry*
  • DNA, Catalytic / chemistry*
  • DNA, Catalytic / metabolism
  • DNA, Single-Stranded / analysis
  • G-Quadruplexes*
  • Hydrogen Peroxide / chemistry
  • Inverted Repeat Sequences
  • Oligonucleotide Probes / chemistry*
  • Oxidation-Reduction
  • Thrombin / analysis

Substances

  • Benzidines
  • DNA, Catalytic
  • DNA, Single-Stranded
  • Oligonucleotide Probes
  • 3,3',5,5'-tetramethylbenzidine
  • Hydrogen Peroxide
  • Thrombin