Quantitative analysis of extension-torsion coupling of actin filaments
Quantitative analysis of extension-torsion coupling of actin filaments
复制标题
肌动蛋白丝伸扭耦合的定量分析
DOI：
10.1016/j.bbrc.2012.02.048
复制
发表时间：
2012
影响因子：
3.1
通讯作者：
Taiji Adachi
中科院分区：
文献类型：
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作者：
Shinji Matsushita;Yasuhiro Inoue;Taiji Adachi
肌动蛋白丝具有由球状肌动蛋白分子组成的双螺旋结构。在许多机械细胞活动中，例如细胞运动、分裂和形状控制，丝的拉伸和扭转动力学的调节与调节肌动蛋白结合蛋白的功能有关。因此，定量评估肌动蛋白丝的延伸-扭转耦合对于更好地了解肌动蛋白丝动力学非常重要。在本研究中，利用分子动力学模拟研究了延伸-扭转耦合。我们在离子溶剂中构建了由 14 个肌动蛋白亚基组成的肌动蛋白丝作为最小功能单元的模型，并分析了肌动蛋白丝的纵向和扭转布朗运动。然后，我们得出了与平衡时延伸和扭转相关的能量预期值，并根据 MD 模拟获得的热波动评估了细丝的延伸-扭转刚度。结果表明，随着分析的采样窗口持续时间的增加，纳秒尺度上评估的伸扭耦合刚度趋于收敛到 7.6×10−11N 的值。这项研究获得的结果将有助于理解机械张力和扭矩下的生物力学事件，涉及细丝的延伸-扭转耦合。
Actin filaments have a double-helix structure consisting of globular actin molecules. In many mechanical cellular activities, such as cell movement, division, and shape control, modulation of the extensional and torsional dynamics of the filament has been linked to regulatory actin-binding protein functions. Therefore, it is important to quantitatively evaluate extension–torsion coupling of filament to better understand the actin filament dynamics. In the present study, the extension–torsion coupling was investigated using molecular dynamics simulations. We constructed a model for the actin filament consisting of 14 actin subunits in an ionic solvent as a minimal functional unit, and analyzed longitudinal and twisting Brownian motions of the filament. We then derived the expected value of energy associated with extension and torsion at equilibrium, and evaluated the extension–torsion stiffness of the filament from the thermal fluctuations obtained from the MD simulations. The results demonstrated that as the analyzed sampling-window duration was increased, the extension–torsion coupling stiffness evaluated on a nanosecond scale tended to converge to a value of 7.6×10−11N. The results obtained from this study will contribute to the understanding of biomechanical events, under mechanical tension and torque, involving extension–torsion coupling of filaments.