Fluorescence reporting of G-quadruplex structures and modulating their DNAzyme activity using polyethylenimine–pyrene conjugate

Four-stranded G-quadruplex structure is one of the most important non-canonical secondary structures of DNA formed by guanine (G)-rich sequences. G-rich DNA sequences are known to occur in the human genome, especially in the telomere 3′ end and in oncogene promoters such as c-MYC and c-KIT. In this context, we designed pyrene-conjugated polyethylenimine (PEI–Py) as a fluorescence reporter for the recognition and detection of G-quadruplex structures of G-rich deoxyoligonucleotides and human telomere and gene promoter sequences, under ambient conditions. PEI–Py exhibited prominent pyrene excimer emission in the presence of G-quadruplex structures of G-rich deoxyoligonucleotides and biologically relevant DNA sequences. PEI–Py further displayed the modulation of DNAzyme activity of various G-quadruplex structures in the presence of hemin and hydrogen peroxide.

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