Department of Molecular Cellbiology, University of Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
Photosynth Res. 1988 Apr;16(1-2):177-86. doi: 10.1007/BF00039492.
Many proteins found in the chloroplast are synthesized in the cytoplasm as precursor molecules containing transit peptides. Proteins targeted to the stroma must pass through the two envelope membranes to reach their destination. Proteins located in the chloroplast lumen also have to be transferred across the thylakoid membrane. That is, lumen proteins must cross three biological membranes in order to reach their final location. Recent evidence shows that the routing of plastocyanin towards the lumen involves two post-translational transport processes mediated by two different regions of the transit peptide and two different processing proteases. It is postulated that the genetic information for the plastocyanin precursor, which already contained a signal peptide, was transferred from the endosymbiont to the nucleus. Then a chloroplast-specific targeting-peptide was added.
叶绿体内许多蛋白质作为含有转运肽的前体分子在细胞质中合成。靶向基质的蛋白质必须穿过两个包膜才能到达目的地。位于类囊体腔中的蛋白质也必须穿过类囊体膜转移。也就是说，腔室蛋白必须穿过三个生物膜才能到达其最终位置。最近的证据表明，质体蓝素向腔室的路由涉及两个由不同的转运肽区域和两种不同的加工蛋白酶介导的翻译后运输过程。据推测，质体蓝素前体的遗传信息，已经包含一个信号肽，从内共生体转移到细胞核。然后添加了一个叶绿体特异性靶向肽。
