Molecular orientation distributions in protein films:: III.: Yeast cytochrome c immobilized on pyridyl disulfide-capped phospholipid bilayers
Molecular orientation distributions in protein films:: III.: Yeast cytochrome c immobilized on pyridyl disulfide-capped phospholipid bilayers
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DOI：
10.1016/s0006-3495(98)74024-x
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发表时间：
1998-02-01
影响因子：
3.4
通讯作者：
Saavedra, SS
中科院分区：
文献类型：
--
作者：
Edmiston, PL;Saavedra, SS
研究了酵母细胞色素 c 的水合单层膜中的分子取向，该膜通过 Cys-102 和从空气-水界面沉积到玻璃基板上的吡啶基二硫化物封端的磷脂双层之间的二硫键固定。使用吸收线性二色性（在平面集成光波导衰减全反射几何结构中测量）和荧光各向异性（在全内反射几何结构中测量）的组合来确定蛋白质膜中血红素基团的取向分布。使用取向分布的高斯模型来恢复平均血红素倾斜角和关于平均值的角度分布，分别为40度和11度。其他实验表明，大部分细胞色素 c 通过二硫键与双层结合，这与蛋白质膜中的高度宏观有序相关。然而，薄膜中的酵母细胞色素 c 分子亚群（约占总数的 30%）似乎被非特异性吸附。发现该亚群的取向分布比特定结合的部分宽得多。
Molecular orientation in a hydrated monolayer film of yeast cytochrome c, immobilized via disulfide bonding between Cys-102 and a pyridyl disulfide-capped phospholipid bilayer deposited from an air-water interface onto glass substrates, was investigated. The orientation distribution of the heme groups in the protein film was determined using a combination of absorption linear dichroism, measured in a planarintegrated optical waveguide-attenuated total reflection geometry-and fluorescence anisotropy, measured in a total internal reflection geometry. A gaussian model for the orientation distribution was used to recover the mean heme tilt angle and angular distribution about the mean, which were 40 and 11 degrees, respectively. Additional experiments showed that a large fraction of the cytochrome c was disulfide bonded to the bilayer, which correlates with the high degree of macroscopic order in the protein film. However, a subpopulation of yeast cytochrome c molecules in the film (similar to 30% of the total) appeared to be nonspecifically adsorbed. The orientation distribution of this subpopulation was found to be much broader than the specifically bound fraction.