脂质体对细胞色素C结构的稳定作用

采用同步荧光光谱考察细胞色素C(CytC)在脂质体环境中分子内基团微环境的变化,推测分子的空间构象。结果表明:CytC结合到脂质体上引起分子内基团重新组装和排布,氨基酸残基所处的微环境发生明显变化,体现在荧光光谱上,酪氨酸和色氨酸的光活性增强,色氨酸在水溶液中的分子内电荷转移得到抑制,此过程不涉及化学键的断裂。在脂质体环境中,尿素引起的CytC解聚变性效应得到明显抑制,脂质体与尿素在促进CytC分子内氨基酸残基发光上有协同效应。

Structural Stability of Cytochrome C in Egg Phosphatidylcholine Liposomes

The fluorescence spectra of tyrosine and tryptophan residues in cytochrome (Cyt C) were obtained in this paper through controlling △λ in synchronous fluorescence. The changes of spectra in egg phosphatidylcholine(PC) liposomes reflects the micro-environment of groups in Cyt C and the steric conformation. Our experiments showed that the binding of Cyt C to liposomes led to the re-selfassembly among the goups in Cyt C, and luminescence activity of amino acids residues enhanced markedly. The re-selfassembly process was not involved in chemical bond damage. Intramolecular electro transfer related with tryptophan residues was inhibited after binding to liposomes. The existence of liposomes could inhibit the chemical denaturant of Cyt C in urea, but the synergies happened between liposomes and urea in luminescence activity enhancement.