Synthesis Of Analog-BRC2 And Interaction Of Analog-BRC2 With Peptide P53(171-192)

The formation of cancer involves changes in multiple genes and their products, these changes lead to the cell hyperplasia is out of control and causes the cancer. This is one of the reasons why overcoming cancer is difficult. Breast cancer susceptibility gene 2(BRCA2) is an important tumor suppressor gene, which is involved in DNA damage repair, cell cycle regulation and transcriptional regulation and other functions. The p53 protein is a master regulatory protein involved in cellular processes, if p53 protein want to exercise its functions, it need to BRCA2 and its products to its regulation. Therefore, the study of the interaction between BRCA2 and p53, for a better understanding of the pathogenesis of breast cancer and its subsequent treatment has a very important value.In this thesis, the repeated motif BRC2 in BRCA2 was selected and the p53(171-192) was selected as the target peptide. 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 target peptide p53(171-192) and a series of classes BRC2 peptide. Crude peptides isolated and purified by reverse phase high performance liquid chromatography(RP-HPLC), and characterized by mass spectrometry. The results obtained showed that synthesis product was the desired target peptide chain, and their purity reached more than 90%.The interaction between p53(171-192) and analog-BRC2 peptides had been investigated by using circular dichroism spectrum and fluorescence spectroscopy. The circular dichroism spectroscopy results showed that: with the steady increased the concentration of analog-BRC2, the strength of circular dichroism absorption peaks have changed, and the wavelength position appeared red shift or blue shift. The change caused by analog-BRC2-1 peptide was bigger than the change caused by other analog-BRC2 peptides. This phenomenon may be due to glutamine(Gln) in BRC2 replaced by hydrophobic proline(Pro) in analog-BRC2-1, resulting in a strong structure change of p53(171-192). From the results of fluorescence spectroscopy we could be drawn: with the target peptide p53(171-192) concentration increasing, the fluorescence intensity of analog-BRC2 peptides decreased. This phenomenon may be due to based on the aromatic amino acids phenylalanine(Phe) replaced hydrophobic proline(Pro), so that π-π stacking interactions weaken. Therefore, the degree of quenching analog-BRC2-2 weaker than the degree of analog-BRC2-1. Combined results of the two spectroscopy studies, we could realized that there have interactions between the analog-BRC2 peptides and p53(171-192).