MULTIPLE PATHWAYS FOR PROTEIN-TRANSPORT INTO OR ACROSS THE THYLAKOID MEMBRANE
MULTIPLE PATHWAYS FOR PROTEIN-TRANSPORT INTO OR ACROSS THE THYLAKOID MEMBRANE
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DOI：
10.1002/j.1460-2075.1993.tb06094.x
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发表时间：
1993-11-01
期刊：
影响因子：
11.4
通讯作者：
YUAN, JG
中科院分区：
文献类型：
--
作者：
CLINE, K;HENRY, R;YUAN, JG
许多类囊体蛋白质是在细胞质中合成的，它们必须穿过两层叶绿体被膜和类囊体膜才能到达它们的功能位置。为了研究这些蛋白的定位途径，我们在大肠杆菌中过量表达前体蛋白，并将其用于竞争研究。竞争进行输入到叶绿体和运输到或跨越孤立的类囊体。我们还开发了一种新的在organello方法，其中竞争类囊体运输发生在完整的叶绿体。进口的所有前体进入叶绿体同样受到抑制的饱和浓度的前体的OE23蛋白。相反，类囊体运输的竞争揭示了三个不同的前体特异性组。腔驻留蛋白OE23和OE17构成一组，腔蛋白质体蓝素和OE33构成第二组，膜蛋白LHCP构成第三组。由竞争确定的特异性与先前确定的蛋白质特定的类囊体运输的能量需求相关。两者合计，这些结果表明，类囊体前体蛋白进口到叶绿体上的一个共同的进口设备，于是他们进入一个特定的类囊体运输途径。
Many thylakoid proteins are cytosolically synthesized and have to cross the two chloroplast envelope membranes as well as the thylakoid membrane en route to their functional locations. In order to investigate the localization pathways of these proteins, we over-expressed precursor proteins in Escherichia coli and used them in competition studies. Competition was conducted for import into the chloroplast and for transport into or across isolated thylakoids. We also developed a novel in organello method whereby competition for thylakoid transport occurred within intact chloroplasts. Import of all precursors into chloroplasts was similarly inhibited by saturating concentrations of the precursor to the OE23 protein. In contrast, competition for thylakoid transport revealed three distinct precursor specificity groups. Lumen-resident proteins OE23 and OE17 constitute one group, lumenal proteins plastocyanin and OE33 a second, and the membrane protein LHCP a third. The specificity determined by competition correlates with previously determined protein-specific energy requirements for thylakoid transport. Taken together, these results suggest that thylakoid precursor proteins are imported into chloroplasts on a common import apparatus, whereupon they enter one of several precursor-specific thylakoid transport pathways.