Biogenic regions of cyanobacterial thylakoids form contact sites with the plasma membrane
Biogenic regions of cyanobacterial thylakoids form contact sites with the plasma membrane
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DOI：
10.1038/s41477-019-0399-7
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发表时间：
2019-04-01
期刊：
影响因子：
18
通讯作者：
Engel, Benjamin D.
中科院分区：
文献类型：
--
作者：
Rast, Anna;Schaffer, Miroslava;Engel, Benjamin D.
在类囊体膜的生物发生过程中，光合机制在时间和空间上是如何安排的，目前还知之甚少。使用原位冷冻电子断层扫描成像的三维结构的蓝藻集胞藻，我们观察到，多个类囊体的尖端合并，形成一个子结构称为“会聚膜”。这种高曲率膜在离散位点与质膜紧密接触。我们生成了7OS核糖体和阵列形成藻胆体的subtomograph平均值，然后将这些结构映射到天然膜结构上，分别作为蛋白质合成和光合作用的标记。这种分子定位确定了两个不同的生物区的类囊体网络：类囊体面临的细胞的细胞质内部与两个标记复合物，和收敛膜，由核糖体，但不是藻胆体装饰。我们建议，收敛膜执行一个专门的生物功能，耦合类囊体蛋白的合成与质膜和周质空间的辅因子的整合。
Little is known about how the photosynthetic machinery is arranged in time and space during the biogenesis of thylakoid membranes. Using in situ cryo-electron tomography to image the three-dimensional architecture of the cyanobacterium Synechocystis, we observed that the tips of multiple thylakoids merge to form a substructure called the 'convergence membrane'. This high-curvature membrane comes into close contact with the plasma membrane at discrete sites. We generated subtomogram averages of 7OS ribosomes and array-forming phycobilisomes, then mapped these structures onto the native membrane architecture as markers for protein synthesis and photosynthesis, respectively. This molecular localization identified two distinct biogenic regions in the thylakoid network: thylakoids facing the cytosolic interior of the cell that were associated with both marker complexes, and convergence membranes that were decorated by ribosomes but not phycobilisomes. We propose that the convergence membranes perform a specialized biogenic function, coupling the synthesis of thylakoid proteins with the integration of cofactors from the plasma membrane and the periplasmic space.