乙醇对细胞色素c和脱辅基细胞色素c的结构转换影响  

Conformational Transition of Cytochrome c and Apocytochrome c Induced by Ethanol

作　　者：龚洁[1] 姚萍[2] 金岚[1] 江明[1] 淳于俐娟[1] 

机构地区：[1]复旦大学高分子科学系,上海200433 [2]复旦大学遗传学研究所,上海200433

出　　处：《复旦学报（自然科学版）》2001年第4期355-359,363,共6页Journal of Fudan University：Natural Science

基　　金：高等学校骨干教师资助计划 ;国家自然科学基金资助项目 (2 0 0 740 0 6 )

摘　　要：用紫外 可见吸收光谱、荧光光谱和圆二色谱对细胞色素c和脱辅基细胞色素c在不同的 φ(乙醇 )溶液中的结构进行了表征 .结果表明 ,乙醇对细胞色素c的α 螺旋二级结构影响很小 ,而对血红素配位的影响十分明显 ,可导致血红素Fe Met80配位键断裂 .另一方面 ,乙醇对脱辅基细胞色素c有明显的结构转换诱导作用 ,在　φ(C2 H5OH) =0 .5 5 (乙醇 /水 )溶液中 ,脱辅基细胞色素c的α 螺旋结构含量可以达到全蛋白的 89% .研究结果表明 :负电荷微环境的诱导对脱辅基细胞色素c的结构转换并不是必要的 ,改变溶剂与脱辅基细胞色素c之间的疏水和氢键相互作用力也可以诱导脱辅基细胞色素cαThe effects of ethanol on the structure of cytochrome c and apocytochrome c in different concentration ethanol/water cosolvent were investigated through tryptophan fluorescence,UV visible absorption and circular dichroism.The result show that the effect of ethanol to the α helix second order structure is not significant ,but is very obvious to the heme coordination ,resulting in cleaving the coordination of the iron atom of the heme with Met80.On the other hand,ethanol has apparent induction effect to the apocytochrome c conformational transition the α helix content of apocytochrome c in 0.55(φ(C 2H 5OH)) solution may reach up to 89% of the holo protein .The results of this study show that the induction of a negative charge micro environ ment is nto necessary for the conformational transition of apocytochrome c ,the changes of hydrophobic and hydrogen bonds interaction between the ethanol water cosolvent and apocytochrome c can induce the formation of α helix of apocytochrome c.

关 键 词：细胞色素C 脱辅基细胞色素c 结构转换 乙醇 蛋白质 诱导作用 折叠机理 

分 类 号：Q516[生物学—生物化学]