摘要
Transcription factor SPI is a protcin present in mammalian cells that binds to GC box promoter clements of Gene and selectively activates mRNA synthesis. The gene contains functional recognition sites. It contains three continuous zinc finger motifs, which are believed being mctalloprotein structures that interact with DNA. We synthesized the second zine finger fragment of SP1 (SP1-ZF2) and its mutant (SP1-ZF2 / HT. E20→H. R23→T), we also synthesized the Cys-Cys loop (ZF6) and the His-His loop (ZF5) of SPI and linked the twoloops together using a β-turn structure to obtain a finger mimic analogue (ZF-15) by stepwise solid-phase technique. Atomic absorption studies show that SP 1-ZF2 and SP1-ZF2 / HT bind zinc cquimolarly, but ZF-15 docs not bind Zn anyway. The CD experiments demonstrate a significant change in secondary structure in the prescnce or absence of Zn to SP1-ZF2 and SP1-ZF2/ HT, but there is no change about ZF-15. Gcl-retardation clectrophoresis assays indicate that SP1-ZF2 binds to DNA sequence specifically in the presence of Zn, but SP1-ZF2 / HT docs not bind as SP 1-ZF2 did. We observed that a single zine finger like SP1-ZF2 is able to bind DNA sequence specifically.
Transcription factor SPI is a protcin present in mammalian cells that binds to GC box promoter clements of Gene and selectively activates mRNA synthesis. The gene contains functional recognition sites. It contains three continuous zinc finger motifs, which are believed being mctalloprotein structures that interact with DNA. We synthesized the second zine finger fragment of SP1 (SP1-ZF2) and its mutant (SP1-ZF2 / HT. E20→H. R23→T), we also synthesized the Cys-Cys loop (ZF6) and the His-His loop (ZF5) of SPI and linked the twoloops together using a β-turn structure to obtain a finger mimic analogue (ZF-15) by stepwise solid-phase technique. Atomic absorption studies show that SP 1-ZF2 and SP1-ZF2 / HT bind zinc cquimolarly, but ZF-15 docs not bind Zn anyway. The CD experiments demonstrate a significant change in secondary structure in the prescnce or absence of Zn to SP1-ZF2 and SP1-ZF2/ HT, but there is no change about ZF-15. Gcl-retardation clectrophoresis assays indicate that SP1-ZF2 binds to DNA sequence specifically in the presence of Zn, but SP1-ZF2 / HT docs not bind as SP 1-ZF2 did. We observed that a single zine finger like SP1-ZF2 is able to bind DNA sequence specifically.
