Atomic-level models of the bacterial carboxysome shell
Atomic-level models of the bacterial carboxysome shell
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DOI：
10.1126/science.1151458
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发表时间：
2008-02-22
期刊：
影响因子：
56.9
通讯作者：
Yeates, Todd O.
中科院分区：
文献类型：
--
作者：
Tanaka, Shiho;Kerfeld, Cheryl A.;Yeates, Todd O.
羧酸体是细菌的一种微室，其功能是作为一个简单的细胞器，通过隔离参与碳固定的酶。羧基体的外壳直径约为800至1400埃，由数千个蛋白质亚基组装而成。先前的研究已经揭示了六聚体羧基壳蛋白的三维结构，它们自组装成分子层，很可能构成多面体壳的各个面。在这里，我们报道了两种以前未知功能的蛋白质CcmL和OrfA（或CsoS4A）的三维结构，它们来自两种已知的羧酸体，分辨率为2.4和2.15埃。这两种蛋白质组装形成五聚体结构，其大小和形状与二十面体壳中顶点的形成一致。将这些五聚体与先前阐明的六聚体结合起来，给出了两个似是而非的羧基体外壳的初步原子模型。
The carboxysome is a bacterial microcompartment that functions as a simple organelle by sequestering enzymes involved in carbon fixation. The carboxysome shell is roughly 800 to 1400 angstroms in diameter and is assembled from several thousand protein subunits. Previous studies have revealed the three- dimensional structures of hexameric carboxysome shell proteins, which self- assemble into molecular layers that most likely constitute the facets of the polyhedral shell. Here, we report the three- dimensional structures of two proteins of previously unknown function, CcmL and OrfA ( or CsoS4A), from the two known classes of carboxysomes, at resolutions of 2.4 and 2.15 angstroms. Both proteins assemble to form pentameric structures whose size and shape are compatible with formation of vertices in an icosahedral shell. Combining these pentamers with the hexamers previously elucidated gives two plausible, preliminary atomic models for the carboxysome shell.