A GTP-driven motor moves proteins across the outer envelope of chloroplasts
A GTP-driven motor moves proteins across the outer envelope of chloroplasts
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GTP 驱动的马达将蛋白质移动穿过叶绿体的外膜
DOI：
10.1073/pnas.0730860100
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发表时间：
2003
影响因子：
11.1
通讯作者：
J. Soll
中科院分区：
文献类型：
--
作者：
E. Schleiff;M. Jelić;J. Soll
蛋白质跨细胞膜的转运是每个细胞的关键机制问题。位于叶绿体外被膜上的前体蛋白转运子负责前体蛋白的识别和跨外被膜的转运。我们已经从单个亚基或通过使用纯化的易位子将易位过程重建到蛋白脂体中。前体蛋白在初始GTP依赖性过程中被Toc34受体识别。然后在GTP依赖性过程中通过Toc75通道发生跨膜平面的易位。相应地，GTP水解的TOC蛋白脂质体是100倍增强的前蛋白的存在下。通过基质加工肽酶将前体形式加工成成熟形式和通过输入蛋白的蛋白酶抗性来证明完全易位。分子伴侣不参与这种易位事件。我们表明，Toc 159在类似缝纫机的机构中充当了GTP驱动的电机。
The translocation of proteins across cellular membranes is a key mechanistic problem for every cell. The preprotein translocon at the chloroplast outer envelope is responsible for precursor protein recognition and translocation across the outer envelope. We have reconstituted the translocation process into proteoliposomes from single subunits or by using the purified translocon. Precursor proteins are recognized by the Toc34 receptor in an initial GTP-dependent process. Translocation across the plane of the membrane then occurs through the Toc75 channel in a GTP-dependent process. Correspondingly, GTP hydrolysis of Toc proteoliposomes is 100-fold enhanced in the presence of preprotein. Complete translocation is demonstrated by processing of the precursor form to the mature form by the stromal processing peptidase and by protease resistance of the imported protein. Molecular chaperones are not involved in this translocation event. We show that Toc159 acts as a GTP-driven motor in a sewing-machine-like mechanism.