| Summary: | 碩士 === 東海大學 === 化學系 === 98 === Overexpression of Id proteins which are negative regulators of DNA transcription results in the invasion and Metastasis of tumors. Ferric nitrilotriacetate (Fe-NTA), a complex of ethylenediaminetetraacetic acid (EDTA) chelated with the iron (Ⅲ) ion, exhibited the effect of degradation of Id1 protein by redox reaction. We designed a series of peptides (peptides DIB1, DIB2, and DIB3) on the basis of the structure of EDTA, synthesized these peptides by solid phase peptide synthesis, and evaluated effects of these peptides on recognition and degradation of Id1 protein by mass spectrometry and cell viability assay. Results of the chelation and degradation experiments showed that peptide DIB1 not only chelated with the iron (Ⅲ) ion and the copper (Ⅱ) ion, but also degraded protein such as bovine serum albumin (BSA). Peptide DIB2 recognized and degraded the Id1 protein. When chelated with the copper (Ⅱ) ion, peptides DIB1 and DIB2 exhibited stronger degradation effect on protein than the effect of those chelated with the iron (Ⅲ) ion. The effect of peptide DIB3 chelated with the iron (Ⅲ) ion on degradation of Id1 protein was lower than the effect of peptide DIB2 which chelated with the iron (Ⅲ) ion at the same concentration. Furthermore, peptide DIB1 was assayed for its in vitro activity in human breast cancer cells MCF-7. Results showed that peptide DIB1 did not exhibit the antiproliferative effect in MCF-7 cancer cells. Taken together, peptide DIB1 had the effect of degradation on protein and peptide DIB2 can degrade Id1 protein specifically. We suggest that the amino acid sequence of peptide DIB1 would not affect the interactions between peptide 3C and Id1 protein, rather, it exhibited stronger degradation effect on Id protein when it was chelated with the copper (Ⅱ) ion.
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