Colorimetric split G-quadruplex probes for nucleic acid sensing: improving reconstituted DNAzyme's catalytic efficiency via probe remodeling

J Am Chem Soc. 2009 Jul 29;131(29):10320-33. doi: 10.1021/ja902951b.

Abstract

Split G-rich DNA probes can assemble into active peroxidase-mimicking DNAzymes in the presence of bioanalytes such as DNA, thereby providing a simple and cheap means to detect analytes in biological samples. A comprehensive study designed to reveal the salient probe architectural features and reaction conditions that facilitate facile reconstitution into enzymatically proficient enzymes unveiled these important findings: (a) The loops that connect the G3-tracts in a G-quadruplex structure can be replaced with a stem-loop or loop-stem-loop motif without destabilizing the resulting quadruplex structure; endowing the split G-rich probes with regions of limited complementarity leads to more proficient reconstituted enzymes. (b) The addition of hemin to antiparallel G-quadruplex DNAzymes lead to a blue shift in the CD spectra of the G-quadruplex DNAzymes. (c) The architectures of the DNA motifs that lie adjacent to the G-quadruplex structure influence both the stability and the enzymatic proficiency of the reconstituted enzymes. (d) The nature of the monovalent cation that is present in excess is a key determinant of the turnover number of the G-quadruplex DNAzyme; decomposition of G-quadruplex DNAzymes is slower in buffers that contain ammonium ions than those that contain sodium or potassium ions. These findings are important for the design of bioassays that use peroxidase-mimicking G-quadruplexes as detection labels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aptamers, Nucleotide / analysis
  • Aptamers, Nucleotide / chemistry*
  • Biocatalysis
  • Colorimetry
  • DNA, Catalytic / chemistry
  • DNA, Catalytic / metabolism*
  • G-Quadruplexes*
  • Molecular Structure
  • Nucleic Acids / analysis*
  • Nucleic Acids / chemistry*

Substances

  • Aptamers, Nucleotide
  • DNA, Catalytic
  • Nucleic Acids