Dynamics of a Protein Chain Motor Driving Helical Bacteria under Stress.
Dynamics of a Protein Chain Motor Driving Helical Bacteria under Stress.
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压力下驱动螺旋细菌的蛋白链马达动力学
DOI：
10.1016/j.bpj.2018.02.043
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发表时间：
2018
影响因子：
3.4
通讯作者：
Rohrbach A.
中科院分区：
文献类型：
--
作者：
Roth J;Koch M. D;Rohrbach A.
无壁螺旋细菌属Spiroplasma具有独特的推进系统;它不是由螺旋桨状鞭毛驱动，而是由膜结合的细胞质线性马达驱动，该马达由跨越整个细胞长度的相同蛋白质的收缩链组成。通过蛋白质构象变化的协调传播，扭结沿着细胞体成对沿着传播。然而，扭结的启动或延迟及其协调传播的机制仍不清楚。在这里，我们展示了我们如何操纵扭结的起始，它们的传播速度，以及两个扭结之间的时间为一个单一的细胞被困在一个光学线电位。通过干涉三维形状跟踪，我们测量了细胞对各种外部应力情况的变形。我们观察到力的产生对细胞局部配体浓度（可能是ATP）和配体水解的显著依赖性，我们以不同的方式改变了这一点。我们开发了一个机械的，数学模型的基础上克雷默的速率，描述随后的合作和构象转换链的蛋白质。该模型再现了我们的实验观察，并可以解释变形特性，即使当电机驱动到其极限。大自然发明了一套极简主义的机械驱动概念。为了理解甚至重建它们，揭示这种蛋白质链马达的分子机制是至关重要的，这种马达只需要两种成分偶联的蛋白质和配体就可以发挥作用。
The wall-less, helical bacterial genusSpiroplasmahas a unique propulsion system; it is not driven by propeller-like flagella but by a membrane-bound, cytoplasmic, linear motor that consists of a contractile chain of identical proteins spanning the entire cell length. By a coordinated spread of conformational changes of the proteins, kinks propagate in pairs along the cell body. However, the mechanisms for the initiation or delay of kinks and their coordinated spread remain unclear. Here, we show how we manipulate the initiation of kinks, their propagation velocities, and the time between two kinks for a single cell trapped in an optical line potential. By interferometric three-dimensional shape tracking, we measured the cells' deformations in response to various external stress situations. We observed a significant dependency of force generation on the cells' local ligand concentrations (likely ATP) and ligand hydrolysis, which we altered in different ways. We developed a mechanistic, mathematical model based on Kramer's rates, describing the subsequent cooperative and conformational switching of the chain's proteins. The model reproduces our experimental observations and can explain deformation characteristics even when the motor is driven to its extreme. Nature has invented a set of minimalistic mechanical driving concepts. To understand or even rebuild them, it is essential to reveal the molecular mechanisms of such protein chain motors, which need only two components—coupled proteins and ligands—to function.
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影响因子：
3.4
作者：
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通讯作者：
Puglisi, Joseph D.
影响因子：
35
作者：
Koch, Matthias;Rohrbach, Alexander
通讯作者：
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影响因子：
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作者：
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软体的运动性。
影响因子：
3.4
作者：
Wolgemuth,CharlesW;Igoshin,Oleg;Oster,George
通讯作者：
Oster,George
蜜蜂螺原体中的精氨酸/鸟氨酸交换系统
DOI：
--
发表时间：
1995
期刊：
影响因子：
--
作者：
I. Shirazi;M. Tarshis;S. Rottem
通讯作者：
S. Rottem