来自Lactobacillus brevis的叶酸能量合因子载体的晶体结构
Ke Xu1, Minhua Zhang, Qin Zhao
1National Key Laboratory of Plant Molecular Genetics, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
Nature
|April 16, 2013
概括
能量合因子 (ECF) 输送器,这是一个独特的ATP绑定磁带进口器类别,具有结构性特征. 这项研究揭示了组织,并提出了一种运输机制,涉及叶酸ECF载体的结构变化.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 分子运输分子的运输.
背景情况:
- ATP结合盒 (ABC) 运输体是大型蛋白质超级家族,参与由ATP水解驱动的跨膜运输.
- 能量合因子 (ECF) 运输体代表了ABC进口体的独特类别,具有独特的组织和功能性质,缺乏周等离子体溶液结合蛋白.
- 之前的结构研究确定了ECF传送器组件中的基质结合点,但没有阐明整体组织或传输机制.
研究的目的:
- 为了确定来自Lactobacillus brevis的完整的叶酸ECF载体的结构.
- 阐明分子组织,并为ECF传送器提出一个运输机制.
主要方法:
- 采用X射线结晶学来确定完整的叶酸ECF载体的结构.
- 该结构的分辨率为3 Å.
- 传送器被捕获在一个向内面的,无核酸的形状.
主要成果:
- 该结构揭示了四个ECF输送元件的组织:EcfT,EcfA,EcfA',以及基底结合蛋白Folt.
- EcfT采用L形,绑定Folt,并通过合螺旋连接到EcfA和EcfA',其中包含保存的XRX图案,对能量合至关重要.
- 观察到载体处于无核酸,向内转向的状态,这表明运输模型涉及到FOLT的实质性构造变化.
结论:
- 这项研究首次展示了完整的ECF传送器的结构,揭示了其分子架构.
- 提出了ECF传送机制的模型,突出了EcfT合螺旋体的作用和基板运输中的结构变化.
- 这种结构洞察力有助于我们更好地理解一种独特的膜传送器类.
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