利用体外力-运动分析系统研究ATP诱导的肌动蛋白-肌球蛋白滑动的单一距离。

Unitary distance of ATP-induced actin-myosin sliding studied with an in vitro force-movement assay system.

作者信息

Oiwa K, Kawakami T, Sugi H

机构信息

Department of Physiology, School of Medicine, Teikyo University, Tokyo, Japan.

出版信息

Adv Exp Med Biol. 1993;332:313-9. doi: 10.1007/978-1-4615-2872-2_30.

DOI:10.1007/978-1-4615-2872-2_30

PMID:8109345

Abstract

We studied the unitary distance of ATP-induced actin-myosin sliding using an in vitro force-movement assay system consisting of a myosin-coated glass microneedle and well organized actin filament arrays (actin cables) in the internodal cell of an alga Nitellopsis obtusa. The number of myosin heads interacting with actin cables was reduced to about 100, as judged from the isometric force of about 100 pN attained in the presence of 2 mM ATP. When the amount of iontophoretically applied ATP was reduced by decreasing the amount of charge passed through the ATP electrode from 80 to 2 nC, the distance of the ATP-induced actin-myosin sliding decreased almost linearly from about 100 to about 10 nm, no detectable sliding being observed with further reduction of charge through the electrode. The sliding distances with small amounts of ATP (7-16 nC) distributed around integral multiples of 10 nm, suggesting the unitary distance of actin-myosin sliding of about 10 nm.

摘要

我们使用一种体外力-运动检测系统，研究了ATP诱导的肌动蛋白-肌球蛋白滑动的单位距离。该系统由涂有肌球蛋白的玻璃微针和藻类钝节拟丽藻节间细胞中排列良好的肌动蛋白丝阵列（肌动蛋白束）组成。根据在2 mM ATP存在下达到的约100 pN的等长力判断，与肌动蛋白束相互作用的肌球蛋白头部数量减少到约100个。当通过将通过ATP电极的电荷量从80 nC减少到2 nC来减少离子电渗施加的ATP量时，ATP诱导的肌动蛋白-肌球蛋白滑动距离从约100 nm几乎线性下降到约10 nm，随着通过电极的电荷量进一步减少，未观察到可检测到的滑动。少量ATP（7-16 nC）时的滑动距离分布在10 nm的整数倍附近，表明肌动蛋白-肌球蛋白滑动的单位距离约为10 nm。