Toc12, a novel subunit of the intermembrane space preprotein translocon of chloroplasts
Toc12, a novel subunit of the intermembrane space preprotein translocon of chloroplasts
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DOI：
10.1091/mbc.e04-05-0405
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发表时间：
2004-11-01
影响因子：
3.3
通讯作者：
Schleiff, E
中科院分区：
文献类型：
--
作者：
Becker, T;Hritz, J;Schleiff, E
蛋白质跨膜转运对于每个细胞的生物发生是必不可少的，并且通过蛋白质复合物实现。我们分析了从叶绿体的膜间隙的易位复合物，并确定了一个12 kDa的蛋白质与TOC机械。Toc 12是一种外膜蛋白，其可溶性结构域暴露于膜间隙中。Toc 12含有一个J结构域，并刺激DnaK的ATP酶活性。的构象稳定性和刺激热休克蛋白70的能力是依赖于一个二硫桥环区域内的J-结构域，这表明氧化还原调节激活的伴侣。Toc 12与Toc 64和Tic 22相关。它的J结构域将外膜上的Hsp 70募集到膜间隙的易位子上，并促进其与前蛋白的相互作用。
Translocation of proteins across membranes is essential for the biogenesis of each cell and is achieved by proteinaceous complexes. We analyzed the translocation complex of the intermembrane space from chloroplasts and identified a 12-kDa protein associated with the Toc machinery. Toc12 is an outer envelope protein exposing a soluble domain into the intermembrane space. Toc12 contains a J-domain and stimulates the ATPase activity of DnaK. The conformational stability and the ability to stimulate Hsp70 are dependent on a disulfide bridge within the loop region of the J-domain, suggesting a redox-regulated activation of the chaperone. Toc12 is associated with Toc64 and Tic22. Its J-domain recruits the Hsp70 of outer envelope membrane to the intermembrane space translocon and facilitates its interaction to the preprotein.