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G - tetramer small molecules with the fluorescent screening new method

Author: FuLiHui
Tutor: LiBaoXin
School: Shaanxi Normal University
Course: Drug analysis
Keywords: G - tetramer Small molecule ligands Anticancer drug screening Fluorescence analysis SWNTs
CLC: R73-3
Type: Master's thesis
Year: 2011
Downloads: 53
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Abstract

Anticancer drugs play an important role in the treatment of tumors and cancer. Anticancer drug screening is an important part of the anti-cancer drug research. The study shows that the G-tetramer of small molecule ligands is the potential anticancer drugs. G-tetramer as anticancer drug targets for screening small molecules of potential anti-cancer drugs is the focus of current research. This paper establishes two types of filters G-tetramer small molecule ligands fluorescence method. G-tetramer, marking fluorescence method for screening small molecule ligands single-walled carbon nanotubes (SWNTs) have unique physical and chemical properties, and has a strong quenching effect on the fluorescence. The single-stranded DNA can be adsorbed on the surface of SWNTs in, when the fluorescein (FAM)-labeled telomeric DNA (F-gDNA) was mixed with the SWNTs, F-gDNA can be adsorbed to the surface of SWNTs, the fluorescein fluorescence quenching , the fluorescence signal decreases. When the addition of small molecules able to stabilize G-tetramer ligand, the role of the ligand, F-GDNA transition from single-stranded G-tetramer structure, thus falling off from the surface of the SWNTs in the FAM fluorescence signal recovery. Instead of G-tetramer of small molecule ligands not make the F-GDNA structure change, the fluorescence signal of the system will not change significantly. Thus we can Add the change in fluorescence intensity before and after the small molecule ligands to screen small molecule ligands of the G-tetramer. By several different small molecule ligand screening, and combined with the control experiments and circular dichroism spectra of the validation results show that this experiment provides a simple screening potential anticancer drug targets by G-tetramer, effective the new method. Second, non-labeled fluorescent screening G-tetramer small molecule ligands to the G-rich DNA sequence via hydrogen bonding, may be formed under certain conditions, the G-tetramer structure, the center of the G-tetramer formed a hole; heme (hemin) as a small molecule can be fitted in the G-tetramer structure molecular center hole to form a class peroxidase activity of DNAzyme. This G-tetramer body-DNAzyme can H202 efficient catalytic oxidation generates p-hydroxyphenyl acetic acid (HPA, the non-fluorescent substance) are associated two pairs of hydroxyphenylacetic acid (strong reaction of the fluorescent material). Competitive reaction occurs when small molecules join G-tetramer-hemin system (DNAzyme), small molecules with hemin. Small molecule G-tetramer binding capacity higher than that of hemin, the small molecules can be hemin from DNAzyme replaced, while the catalytic activity of hemin is far less than the of DNAzyme. In this way, you can use the fluorescence intensity of the H2O2-HPA system tracer of small molecules with hemin competitive process occurs. Strong G-tetramer ligand may hemin replaced from the G-quadruplex-mers-hemin system down, so that the the H2O2-HPA fluorescence intensity decreases, and for the non-G-tetramer ligand or weak ligand hemin replace out, H2O2-HPA fluorescence intensity of the system is still strong. Accordingly, the change in fluorescence intensity of the H2O2-HPA system, small molecule ligands of G-tetramer simple, sensitive screening. In addition, the combination of the negative and positive control experiments and circular dichroism spectroscopy experiments, the established method was validated.

G - tetramer small molecules with the fluorescent screening new method

Abstract

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