不同解折叠状态鸡心脱血红素细胞色素c分子的表面性质

SURFACE HYDROPHOBICITY OF CHICKEN HEART APOCYTOCHROME C WITH DIFFERENT UNFOLDED STATES

脱血红素细胞色素ｃ的构象与其跨膜转运能力是密切相关的。鸡心脱血红素细胞色素ｃ具有较强的自发折叠的能力，在一定条件下可以得到不同解折叠状态的鸡心脱血红素细胞色素ｃ。本文利用疏水层析、与疏水探针１，８—ＡＮＳ的结合以及色氨酸与结合的ＡＮＳ之间的荧光共振能量转移，比较了不同解折叠状态的鸡心脱血红素细胞色素ｃ分子的表面性质。结果表明，部分折叠的鸡心脱血红素细胞色素ｃ分子获得了一种高度动态的结构，形成了动态的疏水核心；同时，它也具有较强的凝集倾向。这些性质与鸡心脱血红素细胞色素ｃ分子较强的自发折叠能力是一致的，为进一步分析鸡心脱血红素细胞色素ｃ分子的构象及其在跨膜转运过程中与脂的相互作用奠定了基础。

The ability of apocytochrome c to move across lipid bilayer is dependent on its folding states. Chicken heart apocytochrome c has relatively stronger tendency to fold spontaneously,and its different unfolded states (C1, C2, C3) could be obtained in vitro. The surface hydrophobicity of chicken heart apocytochrome c with different unfolded states has been compared by hydrophobic chromatography and by assessing their ability to bind a hydrophobic probe, 1,8-ANS. In addition, the fluorescence resonance energy transfer between the tryptophan residue and the bound 1,8-ANS has also been studied. The results showed that the partially folded chicken heart apocytochrome c has a highly dynamic hydrophobic core and also tends to aggregate, which is consistent with its folding tendency. The implications in the import of apocytochrome c into mitochondria and in its interactions with phospholipids have been discussed.