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Extensions of the worm-like-chain model to tethered active filaments under tension
bioRxiv - Biophysics Pub Date : 2020-07-26 , DOI: 10.1101/2020.07.26.222273
Xinyu Liao , Prashant K. Purohit , Arvind Gopinath

Intracellular elastic filaments such as microtubules are subject to thermal Brownian noise and active noise generated by molecular motors that convert chemical energy into mechanical work. Similarly, polymers in living fluids such as bacterial suspensions and swarms suffer bending deformations as they interact with single bacteria or with cell clusters. Often these filaments perform mechanical functions and interact with their networked environment through cross-links, or have other similar constraints placed on them. Here we examine the mechanical properties - under tension - of such constrained active filaments under canonical boundary conditions motivated by experiments. Fluctuations in the filament shape are a consequence of two types of random forces - thermal Brownian forces, and activity derived forces with specified time and space correlation functions. We derive force-extension relationships and expressions for the mean square deflections for tethered filaments under various boundary conditions including hinged and clamped constraints. The expressions for hinged-hinged boundary conditions are reminiscent of the worm-like-chain model and feature effective bending moduli and mode-dependent non-thermodynamic effective temperatures controlled by the imposed force and by the activity. Our results provide methods to estimate the activity by measurements of the force- extension relation of the filaments or their mean-square deflections which can be routinely performed using optical traps, tethered particle experiments, or other single molecule techniques.

中文翻译:

蠕虫状链模型在张力作用下扩展为束缚的活性细丝

诸如微管之类的细胞内弹性细丝会受到热布朗噪声和分子电动机产生的主动噪声的影响,而分子电动机会将化学能转化为机械功。同样,活液中的聚合物(例如细菌悬浮液和菌群)在与单个细菌或细胞簇相互作用时会发生弯曲变形。通常,这些细丝执行机械功能并通过交联与其网络环境相互作用,或对其施加其他类似约束。在这里,我们研究了在受实验激励的规范边界条件下,这种受约束的活性细丝在拉伸状态下的机械性能。长丝形状的波动是两种随机力的结果-热布朗力,具有指定时间和空间相关函数的活动派生力。我们推导了在各种边界条件(包括铰接和夹紧约束)下,束缚细丝的力-伸长关系和均方挠度的表达式。铰接铰接边界条件的表达式使人联想到蠕虫状链模型,并具有有效的弯曲模量和受施加的力和活动控制的依赖于模式的非热力学有效温度。我们的结果提供了通过测量细丝的力-延伸关系或其均方偏差来估算活性的方法,这些方法可以使用光阱,束缚粒子实验或其他单分子技术常规进行。我们推导了在各种边界条件(包括铰接和夹紧约束)下,束缚细丝的力-伸长关系和均方挠度的表达式。铰接铰接边界条件的表达式使人联想到蠕虫状链模型,并具有有效的弯曲模量和受施加的力和活动控制的依赖于模式的非热力学有效温度。我们的结果提供了通过测量细丝的力-延伸关系或其均方偏差来估算活性的方法,这些方法可以使用光阱,束缚粒子实验或其他单分子技术常规进行。我们推导了在各种边界条件(包括铰接和夹紧约束)下,束缚细丝的力-伸长关系和均方挠度的表达式。铰接铰接边界条件的表达式使人联想到蠕虫状链模型,并具有有效的弯曲模量和受施加的力和活动控制的依赖于模式的非热力学有效温度。我们的结果提供了通过测量细丝的力-延伸关系或其均方偏差来估算活性的方法,这些方法可以使用光阱,束缚粒子实验或其他单分子技术常规进行。铰接铰接边界条件的表达式使人联想到蠕虫状链模型,并具有有效的弯曲模量和受施加的力和活动控制的依赖于模式的非热力学有效温度。我们的结果提供了通过测量细丝的力-延伸关系或其均方偏差来估算活性的方法,这些方法可以使用光阱,束缚粒子实验或其他单分子技术常规进行。铰接铰接边界条件的表达式使人联想到蠕虫状链模型,并且具有有效的弯曲模量和受施加的力和活动控制的依赖于模式的非热力学有效温度。我们的结果提供了通过测量细丝的力-延伸关系或其均方偏差来估算活性的方法,这些方法可以使用光阱,束缚粒子实验或其他单分子技术常规进行。
更新日期:2020-07-27
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