Design And Synthesis Of C₂H₂ Type Zinc Finger Peptide

Genetic problems has plagued human for a long time. It is an important issue. The genetic transmission and transcription of organisms is worthy of studying and understanding for human.The research about gene regulation factor- zinc finger protein was started from1983. In that year, the first human zinc finger protein RNA polymerase transcriptional regulation factor- TF Ⅲ A was found. Zinc finger proteins are defined as a superfamily with typical zinc finger domain that involved in many aspects of plants growth and development.The zinc finger proteins are mostly exist in animals and plants. They play a very important role in gene regulation, suppression and activation. So the research about zinc finger protein,has very important value to better understand the gene expression and gene therapy.This paper designed two series(A, B), including of nine peptides, by mutanting the specific binding sites- 1, + 2, + 3, + 6 amino acid residues on the α-helix of zinc finger domain. Using FMOC solid phase synthesis, Wang resin as the carrier, HOBT/HBTU/DIEA as coupling reagents, a certain proportion of trifluoroacetic acid/methyl phenyl sulfide/ethanedithiol/water/ phenol as cutting reagent, we synthesized the zinc finger peptide.Crude peptides were isolated and purified by reverse phase high performance liquid chromatography(RP-HPLC), and haracterized by mass spectrometry. The purity of peptide is high.The research about coordination of zinc ions was investigated by using circular dichroism spectrum. The interaction between zinc finger peptide and DNA was investigated by using fluorescence spectroscopy. The results of circular dichroism(CD) spectroscopy showed that the typical secondary structure, α-helix and β-folding had been formed in the zinc finger peptide, with the addition of zinc ions, and suggested that the zinc ions has coordinated to the formnation of zinc finger domain. The results of fluorescence spectroscopy showed that : the fluorescence intensity of the zinc finger peptide weakened gradually with the increasing of the DNA concentration. It proved the interaction between DNA and zinc finger peptide belonged to static quenching,through drawing fluorescence quenching curve. And theinteraction between DNA and ZF-8 was the weakest, the ZF-6 was the strongest. Thus,aromatic amino acid residues will weaken the interaction between DNA and zinc finger peptide, and the introduction of arginine in the zinc finger peptide can significantly improve the ability of the combination of zinc finger and DNA.