Two-Ball Structure of the Flagellar Hook-Length Control Protein FliK as Revealed by High-Speed Atomic Force Microscopy
Two-Ball Structure of the Flagellar Hook-Length Control Protein FliK as Revealed by High-Speed Atomic Force Microscopy
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DOI：
10.1016/j.jmb.2014.11.007
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发表时间：
2015-01-30
影响因子：
5.6
通讯作者：
Aizawa, Shin-Ichi
中科院分区：
文献类型：
--
作者：
Kodera, Noriyuki;Uchida, Kaoru;Aizawa, Shin-Ichi
细菌鞭毛钩是一种短而独特的弯曲管，将基体与细丝连接起来。鼠伤寒沙门氏菌中的可溶性蛋白 FliK 将钩长度平均控制在 55 nm。 FliK 负责测量钩长度的 N 端片段被认为本质上是无序的。在这里，我们通过高速原子力显微镜显示，溶液中的 FliK 分子呈现出由柔性绳连接的两个球的形状；较大的球对应于 N 末端区域，较小的球对应于 C 末端区域。 N 端结构域稳定，但 C 端结构域形状波动。基于 FliK 的这些和其他特征，我们提出，生长钩尖端 N 端片段的折叠在确定钩的最小长度方面起着重要作用。 (C) 2014 年作者。由爱思唯尔有限公司出版
The bacterial flagellar hook is a short and uniquely curved tube that connects the basal body to the filament. Hook length is controlled at 55 nm on average by a soluble protein FliK in Salmonella enterica serovar Typhimurium. The N-terminal segment of FliK responsible for measuring the hook length is considered to be intrinsically disordered. Here, we show by high-speed atomic force microscopy that a FliK molecule in solution takes on a shape of two balls linked by a flexible string; the larger ball corresponds to the N-terminal region and the smaller one corresponds to the C-terminal region. The N-terminal domain is stable but the C-terminal domain fluctuates in shape. Based on these and other features of FliK, we propose that the folding of the N-terminal segment at the tip of the growing hook plays a major role in determining the minimal length of the hook. (C) 2014 The Authors. Published by Elsevier Ltd.