Structure of the cytoskeleton of Spiroplasma melliferum BC3 and its interactions with the cell membrane
Structure of the cytoskeleton of Spiroplasma melliferum BC3 and its interactions with the cell membrane
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DOI：
10.1016/j.jmb.2008.02.020
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发表时间：
2008-05-09
影响因子：
5.6
通讯作者：
Leapman, Richard D.
中科院分区：
文献类型：
--
作者：
Trachtenberg, Shlomo;Dorward, Lori M.;Leapman, Richard D.
意大利螺原体是一种具有动态螺旋对称性的无壁细菌。利用这种原始生命形式的简单性，我们使用了结构（电子断层扫描和冷冻断裂的整个细胞;冷冻电子断层扫描和衍射分析分离的细胞骨架）和蛋白质组学的方法来阐明其最小的基本组织原则。但功能性细胞骨架。从类似的30螺原体蛋白存在于一个高度纯化的细胞骨架部分，我们确定了三个主要的推定结构蛋白：纤维蛋白原，MreB，和延伸因子涂。纤维蛋白组装成一个单一的扁平带，遵循最短的螺旋线下质膜和作为一个线性电机，而MreB是作为一个匹配阵列的膜相关的原纤维平行和相关的电机。我们还确定了一个突出的以前未知的丝状网络，占据了大部分的细胞质，并出现交联的核糖体。丰富的潜在的致突变形成蛋白质延伸因子Tu可能是这个网络的一个组成部分，但断层扫描数据与DNA作为核心成分最一致。这些结果提供了新的信息，最小的组织必要的支持支架和运动功能的最小细胞骨架。(c)2008爱思唯尔有限公司保留所有权利。
Spiroplasma melliferum is a wall-less bacterium with dynamic helical symmetry. Taking advantage of the simplicity of this primitive lifeform, we have used structural (electron tomography and freeze fracture of whole cells; cryoelectron tomography and diffraction analysis of isolated cytoskeletons) and proteomic approaches to elucidate the basic organizing principles of its minimal. yet functional cytoskeleton. From among similar to 30 Spiroplasma proteins present in a highly purified cytoskeletal fraction, we identify three major putative structural proteins: Fib, MreB, and elongation factor Tu. Fib assembles into a single flattened ribbon that follows the shortest helical line just under the plasma membrane and acts as a linear motor, whereas MreB is present as a matching array of membrane-associated fibrils parallel and associated with the motor. We also identify a prominent previously unknown filamentous network that occupies much of the cytoplasm and appears to cross-link the ribosomes. The abundant potentially filament-forming protein elongation factor Tu may be a component of this network, but the tomography data are most consistent with DNA as the core component. The results provide new information on the minimal organization necessary to support the scaffolding and motile functions of a minimal cytoskeleton. (c) 2008 Elsevier Ltd. All rights reserved.