title: Colorimetric split G-quadruplex probes for nucleic acid sensing: improving reconstituted DNAzyme's catalytic efficiency via probe remodeling.
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.
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Nakayama
authors.forename: Herman O
authors.initials: HO
authors.lastname: Sintim
mesh_terms: D052157:Aptamers, Nucleotide / Q000032:analysis / Q000737:chemistry*; D055162:Biocatalysis; D003124:Colorimetry; D021881:DNA, Catalytic / Q000737:chemistry / Q000378:metabolism*; D054856:G-Quadruplexes; D015394:Molecular Structure; D009696:Nucleic Acids / Q000032:analysis* / Q000737:chemistry*
chemical_list: D052157:Aptamers, Nucleotide; D021881:DNA, Catalytic; D009696:Nucleic Acids