Polymer-induced perylene probe excimer formation and selective sensing of DNA methyltransferase activity through the monomer-excimer transition.
A new label-free strategy for sensitive fluorometric biosensing based on perylene probe monomer-excimer transition has been developed. A negatively charged perylene probe (compound 1) was used. Compound 1 shows strong monomer fluorescence in an aqueous buffer solution. A cationic polymer could induce aggregation of compound 1 through noncovalent interactions. Compound 1 monomer emission was quenched, and meanwhile strong excimer emission was observed. Upon addition of a single-stranded DNA (an anionic polymer), strong electrostatic attractive interactions between the cationic polymer and the DNA weakened the binding of aggregates of compound 1 to the polycation. Compound 1 monomers were released, and excimer-monomer emission transition was detected. This observation formed the basis for DNA methyltransferase (MTase) activity detection. When the 3'-OH terminus of a duplex DNA was removed, the DNA strands could not be elongated by terminal deoxynucleotidyl transferase (TdT), and little restoration of compound 1 monomer emission was detected. However, in the presence of MTase and endonuclease, the DNA could be specifically methylated and then cleaved into single-stranded fragments. The DNA fragments contained newly generated 3'-OH termini, which could be elongated by TdT. An excimer-monomer transition signal could then be detected. Simple, sensitive, selective, and inexpensive sensing of DNA methylation was therefore established.
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, People's Republic of China.
Yan
Y
Wang
Jian
J
Chen
Yang
Y
Chen
Wenying
W
Li
Cong
C
Yu
D015254:DNA Modification Methylases / Q000737:chemistry*; D015335:Molecular Probes / Q000737:chemistry*; D010569:Perylene / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
D015335:Molecular Probes; D011108:Polymers; D010569:Perylene; D015254:DNA Modification Methylases