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Nanoscopic analysis of the molecular field for the actinmyosin sliding.

肌动球蛋白滑动分子场的纳米分析。

基本信息

批准号：
07458175
负责人：
YAMADA Takenori
金额：
$ 0.83万
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 (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Recently a retchet model has been proposed for the molecular mechanism of the actomyosin sliding. This model assumes an asymmetric molecular field along actin filament over which a unidirectional thermal diffusion of myosin head takes place. The purpose of the present study is to experimentally detect possible asymmetirc molecular field along myofilaments. The experiments were made on single myofibrils, the contractile unit of skeletal muscle. The molecular field was detected by sliding microbeads on the surface of myofibrils. If an asymmetic molecular field exists on myofilaments, the microbeads may slide with reversed characteristics on the opposite sides of Z-line. Thus we prepared single myofibrils from rabbit skeletal muscle and studied their contractilities. We also developed a laser tweezer system to manupulate microbeads under optical microscope. When microbeads were approached to the surface of myofibrils attached on the surface of glass slide, they firmly adhered with each other and could not make slide by the laser tweezer. So we decided to introduce an atomic force microscope which can study the molecular field with much stronger drawing force. When the tip of cantilever of the atomic force microscope was scanned along the surface of myofibrils, the deflection signal of the cantilever was non-symmetric along the opposite sides of Z-line. Considering the myofilament polarily relative to Z-line, this finding suggests that the molecular field along the myofilament is asymmetric in accord with the ratchet theory. We plan to investigate the internal structure of the molecular field of myofilaments in future.

最近，一个retchet模型已被提出的肌动球蛋白滑动的分子机制。该模型假设肌球蛋白头在沿着肌动蛋白丝的不对称分子场上发生单向热扩散。本研究的目的是从实验上探测肌丝沿着可能存在的非对称分子场。实验是在骨骼肌的收缩单位--单个肌原纤维上进行的。通过在肌原纤维表面滑动微珠来检测分子场。如果肌丝上存在不对称的分子场，则微珠可以在Z线的相对两侧以相反的特性滑动。因此，我们从兔骨骼肌中制备了单个肌原纤维，并研究了它们的收缩性。我们还开发了一个激光镊子系统，在光学显微镜下操纵微珠。当微珠靠近附着在载玻片表面的肌原纤维表面时，它们彼此牢固地粘附，并且不能被激光镊子制成载玻片。所以我们决定引进一种原子力显微镜，它可以用更强的引力来研究分子场。当原子力显微镜的悬臂梁尖端沿肌原纤维表面沿着扫描时，悬臂梁的偏转信号沿Z线的相对两侧沿着是非对称的。考虑到肌丝相对于Z线的极性，这一发现表明，分子场沿着肌丝是不对称的，符合棘轮理论的雅阁。我们计划在未来研究肌丝分子场的内部结构。