Friction measurement between protein-protein by surface forces apparatus

通过表面力装置测量蛋白质-蛋白质之间的摩擦力

基本信息

批准号：
11650157
负责人：
SUDA Hitoshi
金额：
$ 1.66万
依托单位：
TOKAI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

This study was planned to measure friction between protein and protein by using a surface forces apparatus. To perform the plan, proteins have to be arranged monolayer-like on a substrate. As samples of proteins, actin from rabbit skeletal muscle and recombinant myosin subfragment-1 from Dictyosterium were used. These are selected under a background of the possibility that friction occurs in muscle contraction, which is supported by the author's friction theory. Actin molecules were chemically fixed and arranged on the maleimide groups formed on the silica thin film that was made by an ECR sputtering instrument. The adsorption process and the density were measured precisely by using a quartz crystal microbalance. On the other hand, the developed novel in vitro motility assay showed that sliding speed increases exponentially with increasing the applied force. This result suggests that sliding speed is controlled by the adhesion force between actin and myosin as well as activity of ATP hydrolysis. The author presented, here, a possibility that a balance force with the sliding force is a frictional force that is always produced by rubbing two contact bodies. Such friction is well known as Amontons-Coulomb's law or adhesion theory. If the interface of actin and myosin behaves solid-like in the sliding movement, friction occurs naturally even in solution. In this study, rupture dynamics was shown to play a role of their mediation. The dissociation kinetics of weak noncovalent bonds under external forces was first developed by Bell using a phenomenological model for the dissociation rate. Rupture dynamics of molecular adhesion bonds has been investigated on the basis of Brownian dynamics by independently two groups of Evans and Schulten. In the present work, Bell's expression was saved because it was established in various biological specimens. The load-velocity relation was derived through the knowledge of rupture dynamics or non-equilibrium thermodynamics.

该研究计划通过使用表面力设备来测量蛋白质和蛋白质之间的摩擦。为了执行该计划，必须将蛋白质排列在基板上。作为蛋白质的样品，使用了兔骨骼肌的肌动蛋白和dictyosterium的重组肌球蛋白亚纹状1。这些是在肌肉收缩中发生摩擦发生的可能性的背景下选择的，肌肉收缩是由作者的摩擦理论支持的。肌动蛋白分子是化学固定的，并在由ECR溅射仪器制造的二氧化硅薄膜上形成的马来酰亚胺基上排列。通过使用石英晶体微平衡精确测量吸附过程和密度。另一方面，发达的小说体外运动测定法表明，滑动速度随着施加力的增加而指数增加。该结果表明，滑动速度受肌动蛋白和肌球蛋白之间的粘附力以及ATP水解的活性控制。作者在这里提出的是，滑动力的平衡力是一种摩擦力，总是通过摩擦两个接触物体产生的摩擦力。这种摩擦被称为Amontons-Coulomb的定律或粘附理论。如果肌动蛋白和肌球蛋白的界面在滑动运动中的表现类似固体，则摩擦也自然地发生在溶液中。在这项研究中，破裂动态被证明起着其调解的作用。贝尔首先使用现象学模型为解离速率开发了弱非共价键的解离动力学。独立的两组埃文斯和舒尔滕研究了分子粘附键的破裂动力学。在目前的工作中，贝尔的表达之所以保存，是因为它是在各种生物标本中建立的。通过对破裂动力学或非平衡热力学的知识得出了负载速度关系。