Design And Application Fluorescent Probes On Targeting G-Quadruplexes

G-quadruplex,a non-canonical secondary nucleic acid structure,is formed by guanine-rich genomic sequences through Hoogsteen hydrogen bonding.And it widely exists in the promoter region of proto-oncogene and human telomere DNA.Because of the special structure of G-quadruplex,it has potential biological value in regulating telomere length in vivo.Therefore,design and development of G-quadruplex fluorescent probes,especially for G-quadruplex detection probes in living cells,are still of great significance for biomedical applications.And the design and research of the targeted Gquadruplex fluorescent probe mainly includes the following three parts:A novel cyanine dye probe SCY-3,which specifically recognizes G-quadruplex,was designed and synthesized.It is characterized by UV-visible spectroscopy and fluorescence spectroscopy to specifically interact with DNA G-quadruplex,and has little effect with other DNA structures and other biomolecules.In addition,Job Plot and fluorescence quenching experiments were used to demonstrate that SCY-3 binds 1:1 to the 5' end of the G-quadruplex in a terminal packing manner.The cyanine dye SCY-3 is capable of specifically recognizing G-quadruplex and is able to enter cells to monitor lysosomal autophagy in real time.SCY-3 can specifically recognize mitochondrial G-quadruplexes that undergo endocytosis into lysosomes after autophagy,and the fluorescence of SCY-3 gradually increases with autophagy.The cyanine dye MTC can specifically recognize the G-quadruplex,adopts the Gquadruplex structure formed by the oligonucleotide as a template,and uses cysteine as a promoter to regulate the aggregation state of the MTC supramolecules.A multi-channel cysteine detection probe was designed based on changes in its absorption,chirality and fluorescence intensity during MTC conversion.Figure 65;Table 8;Reference 145...