SELECTIVITY CHANGES IN SITE-DIRECTED MUTANTS OF THE VDAC ION CHANNEL - STRUCTURAL IMPLICATIONS
SELECTIVITY CHANGES IN SITE-DIRECTED MUTANTS OF THE VDAC ION CHANNEL - STRUCTURAL IMPLICATIONS
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DOI：
10.1126/science.1690454
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发表时间：
1990-03-09
期刊：
影响因子：
56.9
通讯作者：
FORTE, M
中科院分区：
文献类型：
--
作者：
BLACHLYDYSON, E;PENG, SZ;FORTE, M
对编码酵母线粒体外膜通道VDAC的基因进行定点诱变，以将29个位置的氨基酸改变为电荷不同于野生型序列的残基。然后在酵母中表达突变基因，并在分离突变通道并将其插入磷脂双层后评估单个和多个氨基酸变化的生理后果。在分子长度分布的14个位点观察到选择性变化。这些位点很可能定义了水孔内衬的蛋白质壁的位置，因此也定义了跨膜片段的位置。这些结果已被用于开发通道开放状态的模型，其中每个多肽贡献12 β。链和一个α。螺旋以形成水性跨膜途径。
The gene encoding the yeast mitochondrial outer membrane channel VDAC was subjected to site-directed mutagenesis to change amino acids at 29 positions to residues differing in charge from the wild-type sequence. The mutant genes were then expressed in yeast, and the physiological consequences of single and multiple amino acid changes were assessed after isolation and insertion of mutant channels into phospholipid bilayers. Selectivity changes were observed at 14 sites distributed throughout the length of the molecule. These sites are likely to define the position of the protein walls lining the aqueous pore and hence, the transmembrane segments. These results have been used to develop a model of the open state of the channel in which each polypeptide contributes 12 .beta. strands and one .alpha. helix to form the aqueous transmembrane pathway.