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Molecular Field analysis of the actin-myosin interaction.

肌动蛋白-肌球蛋白相互作用的分子场分析。

基本信息

批准号：
09680658
负责人：
YAMADA Takenori
金额：
$ 2.18万
依托单位：
Science University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09680658/
关键词：
Muscle contraction Actin Myosin Sarcomere Molecular field Atomic force microscope (CONTINUE TO NEXT PAGE)Laser tweezer 生物分子モーター原始間力顕微鏡ミオフィブリル筋収縮筋節

项目摘要

Recently a ratchet model has been proposed for the molecular mechanism of actomyosin sliding where unidirectional thermal diffusion of myosin head takes place along asymmetric molecular field of actin filament. The purpose of the present research is to obtain experimental evidence for asymmetric molecular field along myofilaments. Firstly the contractility of single myofibrils was studied under isometric conditions (Yuri et al., 1998), and then during shortenings (submitted). Then the surface molecular field of myofibril was studied by use of an atomic force microscope to obtain transverse elasticity distribution along sarcomere (Yoshikawa et al., 1999). By analysing the longitudinal and transverse elesticities of myofibril, we found the elasticity of single attached cross-bridge has the structural asymmetry (in preparation). To study the molecular field along actin and myosin filaments in detail, trials were made to prepare cantilever with a ZnO wisker and obtain AFM images of actin and myosin filaments by use of this cantilever. Separately, by use of a laser tweezer system, single actin filament was suspended between two immobilized beads, and a bead coated with myosin was made to slide along the actin filament. By analysing the movements of myosin-coated beads along actin filament, the molecular field present between actin and myosin interface was examined. These studies supported the presence of asymmetric molecular field along myofi1aments, which is in accord with the ratchet theory. Further detailed studies of internal structures of the molecular field of myofilaments are required to clearly the molecular mechanism of muscle contraction.

最近提出了一个棘轮模型来解释肌动球蛋白滑动的分子机制，即肌球蛋白头部的单向热扩散沿沿着肌动蛋白丝的不对称分子场发生。本研究的目的是获得肌丝沿着不对称分子场的实验证据。首先，在等长条件下研究单个肌原纤维的收缩性（Yuri等人，1998年），然后在缩短（提交）。然后通过使用原子力显微镜研究肌原纤维的表面分子场以获得沿沿着的横向弹性分布（Yoshikawa等人，1999年）。通过对肌原纤维纵向和横向弹性的分析，发现单附着横桥的弹性具有结构不对称性。为了研究沿着肌动蛋白和肌球蛋白丝的分子场，尝试用氧化锌晶须制备悬臂梁，并利用该悬臂梁获得肌动蛋白和肌球蛋白丝的AFM图像。另外，通过使用激光镊子系统，将单个肌动蛋白丝悬浮在两个固定的珠之间，并且使涂有肌球蛋白的珠沿着肌动蛋白丝滑动。通过分析肌球蛋白包被的小球沿着肌动蛋白丝的运动，研究了肌动蛋白和肌球蛋白界面之间存在的分子场。这些结果支持了肌纤维中存在沿着分布的不对称分子场，这与棘轮理论是雅阁的。对肌丝分子场内部结构的深入研究，有助于阐明肌肉收缩的分子机制。