神经元尼古丁受体通道域中的突变将离子选择性从阴离子转换为阴离子
J L Galzi1, A Devillers-Thiéry, N Hussy
1Unité de Recherche Associée au Centre National de la Recherche Scientifique D1284, Institut Pasteur, Paris, France.
Nature
|October 8, 1992
概括
通过改变MII段,局部定向突变转化了由乙胆引入的阴离子通道变成离子通道. 蛋白质几何学,特别是未充电的残留物,对于确定这些受体中的离子选择性至关重要.
科学领域:
- 神经科学是一个神经科学.
- 分子生物学分子生物学
- 生物物理学的生物物理.
背景情况:
- 尼古丁酸乙胆受体 (nAChRs) 是阴离子选择性离子通道.
- 甘氨酸和氨酸 (GABA) 受体是阳离子选择性的离子通道.
- MII 部分是离子通道选择性的关键决定因素.
研究的目的:
- 调查MII部分在确定离子选择性的作用.
- 为了将阴离子选择性通道转换为阴离子选择性通道.
- 为了确定影响离子通道功能的关键氨基酸残留物.
主要方法:
- 局部定向突变发生被用来引入突变到阿尔法7尼古丁受体的MII段.
- 来自甘氨酸和GABAA受体的氨基酸被纳入了MII部分.
- 进行了突变受体的功能性表征.
主要成果:
- 从甘氨酸或GABAA受体引入三种氨基酸到α7尼古丁受体的MII段,将其转化为阴离子选择性通道.
- 一个关键的突变涉及在MII的氨基末端插入一个未充电的残留物.
- 这种突变突显了蛋白质对离子选择性的几何约束的重要性.
结论:
- 在决定离子选择性方面,MII部分起着至关重要的作用.
- 蛋白质结构和几何结构对于调节通过道的离子流是必不可少的.
- 乙胆引入的离子通道可以通过特定突变来改变它们的离子选择性.
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Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
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