Protein import into cyanelles and complex chloroplasts
Protein import into cyanelles and complex chloroplasts
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蛋白质输入蓝藻和复杂叶绿体
DOI：
--
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发表时间：
1998
影响因子：
5.1
通讯作者：
W. Löffelhardt
中科院分区：
文献类型：
--
作者：
S. Schwartzbach;T. Osafune;W. Löffelhardt
高等植物的绿藻和红藻叶绿体被双层膜包围。青囊菌质体（cyanelle）在两个包膜之间保留了原核细胞壁。眼虫和甲藻的复杂叶绿体被三层膜包围，而绿蛛植物、隐藻、褐藻、硅藻和其他有色植物的复杂叶绿体被四层膜包围。蓝藻包膜的肽聚糖层和复杂叶绿体的附加膜为叶绿体蛋白输入提供了屏障，而这在较简单的双膜叶绿体包膜中是不存在的。前序列结构分析和体外输入实验表明，蛋白质直接从细胞质穿过两个包膜膜和肽聚糖层输入到蓝藻中。然而，蛋白质输入复杂叶绿体的过程却有着根本的不同。对前序列结构和体外导入微粒体膜的分析表明，转位到内质网是蛋白质导入由三层或四层膜包围的复杂叶绿体的第一步。体内脉冲追踪实验和免疫电子显微镜表明，在眼虫中，蛋白质在穿过三个叶绿体膜之前先从内质网转运到高尔基体。超微结构研究和四个包膜最外层核糖体的存在表明，蛋白质输入到 4 个膜结合的复合叶绿体中是直接从 ER 样的最外层膜进入叶绿体。输入机制的根本区别，翻译后直接叶绿体输入或叶绿体输入之前共翻译易位到内质网，似乎反映了不同叶绿体类型的进化起源。具有双膜包膜的叶绿体被认为是通过真核宿主和光合原核生物之间的初级内共生关联进化而来，而复杂叶绿体被认为是通过异养或可能光养真核宿主和光合真核生物之间的次级内共生关联进化而来。
Higher-plant, green and red algal chloroplasts are surrounded by a double membrane envelope. The glaucocystophyte plastid (cyanelle) has retained a prokaryotic cell wall between the two envelope membranes. The complex chloroplasts of Euglena and dinoflagellates are surrounded by three membranes while the complex chloroplasts of chlorarachniophytes, cryptomonads, brown algae, diatoms and other chromophytes, are surrounded by 4 membranes. The peptidoglycan layer of the cyanelle envelope and the additional membranes of complex chloroplasts provide barriers to chloroplast protein import not present in the simpler double membrane chloroplast envelope. Analysis of presequence structure and in vitro import experiments indicate that proteins are imported directly from the cytoplasm across the two envelope membranes and peptidoglycan layer into cyanelles. Protein import into complex chloroplasts is however fundamentally different. Analysis of presequence structure and in vitro import into microsomal membranes has shown that translocation into the ER is the first step for protein import into complex chloroplasts enclosed by three or four membranes. In vivo pulse chase experiments and immunoelectronmicroscopy have shown that in Euglena, proteins are transported from the ER to the Golgi apparatus prior to import across the three chloroplast membranes. Ultrastructural studies and the presence of ribosomes on the outermost of the four envelope membranes suggests protein import into 4 membrane-bounded complex chloroplasts is directly from the ER like outermost membrane into the chloroplast. The fundamental difference in import mechanisms, post-translational direct chloroplast import or co-translational translocation into the ER prior to chloroplast import, appears to reflect the evolutionary origin of the different chloroplast types. Chloroplasts with a two-membrane envelope are thought to have evolved through the primary endosymbiotic association between a eukaryotic host and a photosynthetic prokaryote while complex chloroplasts are believed to have evolved through a secondary endosymbiotic association between a heterotrophic or possibly phototrophic eukaryotic host and a photosynthetic eukaryote.
细小眼虫叶绿体翻译起始因子 3 的 cDNA 克隆的分离和表征。
DOI：
--
发表时间：
1994
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Lin,Q;Ma,L;Burkhart,W;Spremulli,LL
通讯作者：
Spremulli,LL
光系统 II 的眼虫捕光叶绿素 a/b 结合蛋白的极大且缓慢加工的前体。
DOI：
10.1073/pnas.85.14.5117
发表时间：
1988
影响因子：
11.1
作者：
Rikin,A;Schwartzbach,SD
通讯作者：
Schwartzbach,SD