MOLECULAR DESIGN OF THE VOLTAGE-DEPENDENT, ANION-SELECTIVE CHANNEL IN THE MITOCHONDRIAL OUTER-MEMBRANE
MOLECULAR DESIGN OF THE VOLTAGE-DEPENDENT, ANION-SELECTIVE CHANNEL IN THE MITOCHONDRIAL OUTER-MEMBRANE
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DOI：
10.1006/jsbi.1995.1004
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发表时间：
1995-01-01
影响因子：
3
通讯作者：
MANNELLA, CA
中科院分区：
文献类型：
--
作者：
GUO, XW;SMITH, PR;MANNELLA, CA
线粒体外膜含有大量的通道蛋白VDAC拷贝，这被认为是极性分子和离子通过该膜的主要渗透途径。利用低剂量电子显微镜获得了该通道二维晶体的图像。（通过用磷脂酶A(2)处理真菌线粒体的外膜而产生）嵌入玻璃体冰或氨基葡萄糖。通过旋转相关分析确定了一种阵列单元格中通道的角取向。该蛋白的氨基末端片段（根据圆二色性，在非极性溶剂和洗涤剂溶液中形成α -螺旋）的位置已通过标记阵列确定，该阵列由针对残基1-20的抗体制备而成。通过傅里叶重建方法对嵌入在葡萄糖中的倾斜晶体的投影得到通道的三维结构，然后对单元胞中的三个非对称相关通道进行平均。本研究结果表明，VDAC的管腔壁具有一些不规则特征（高度不均匀，凹槽），并且在这种晶体状态下，氨基端段从管腔延伸。(C) 1995学术出版社，Inc。
The mitochondrial outer membrane contains numerous copies of a channel protein, VDAC, that is thought to be the main permeability pathway through this membrane for polar molecules and ions. Low-dose electron microscopy has been used to obtain images of two-dimensional crystals of this channel. (produced by treating outer membranes from fungal mitochondria with phospholipase A(2)) embedded in vitreous ice or aurothioglucose. The angular orientation of the channels in the unit cell of one type of array has been determined by rotational correlation analysis. The location of the amino-terminal segment of the protein (which, according to circular dichroism, forms an alpha-helix in nonpolar solvents and detergent solutions) has been determined by labeling arrays with Fab prepared from antibodies directed against residues 1-20. The three-dimensional structure of the channel has been obtained by applying Fourier reconstruction methods to projections of tilted crystals embedded in aurothioglucose, followed by averaging of the three non-symmetry-related channels in the unit cell. The results of this study indicate that the wall of VDAC's lumen has several irregular features (uneven height, grooves) and that the aminoterminal segment extends away from the lumen in this crystalline state. (C) 1995 Academic Press, Inc.