Quantitative Detection of G-Quadruplex DNA in Live Cells Based on Photon Counts and Complex Structure Discrimination |
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Authors: | Liu-Yi Liu Dr. Wenting Liu Dr. Kang-Nan Wang Bo-Chen Zhu Xiao-Yu Xia Prof. Dr. Liang-Nian Ji Prof. Dr. Zong-Wan Mao |
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Affiliation: | MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275 P. R. China |
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Abstract: | G-quadruplex DNA show structural polymorphism, leading to challenges in the use of selective recognition probes for the accurate detection of G-quadruplexes in vivo. Herein, we present a tripodal cationic fluorescent probe, NBTE , which showed distinguishable fluorescence lifetime responses between G-quadruplexes and other DNA topologies, and fluorescence quantum yield (Φf) enhancement upon G-quadruplex binding. We determined two NBTE -G-quadruplex complex structures with high Φf values by NMR spectroscopy. The structures indicated NBTE interacted with G-quadruplexes using three arms through π–π stacking, differing from that with duplex DNA using two arms, which rationalized the higher Φf values and lifetime response of NBTE upon G-quadruplex binding. Based on photon counts of FLIM, we detected the percentage of G-quadruplex DNA in live cells with NBTE and found G-quadruplex DNA content in cancer cells is 4-fold that in normal cells, suggesting the potential applications of this probe in cancer cell detection. |
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Keywords: | fluorescence lifetime imaging microscopy fluorescent probes G-quadruplexes photon counts structure elucidation |
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