单肌动球蛋白运动力的力学测量
Mechanical measurements of single actomyosin motor force.
作者信息
Miyata H, Yoshikawa H, Hakozaki H, Suzuki N, Furuno T, Ikegami A, Kinosita K, Nishizaka T, Ishiwata S
机构信息
Department of Physics, Faculty of Science and Technology, Keio University, Yokohama, Japan.
出版信息
Biophys J. 1995 Apr;68(4 Suppl):286S-289S; discussion 289S-290S.
To elucidate the mechanism of force generation by actomyosin motor, a measuring system was constructed, in which an in vitro motility assay was combined with an optical trapping technique. An actin filament of several micron long was attached to a gelsolin-coated polystyrene bead, and was allowed to interact with a small number (approximately 1/1 micron actin filament) of rabbit skeletal heavy meromyosin (an active subfragment of myosin) molecules bound to a nitrocellulose-coated coverglass. The bead position was determined at 33-ms intervals. We measured the force generation event at relatively low (100-400 nM) ATP concentration so that the occurrence of individual force generation events could be detected with our time resolution. The actin-bound bead held in the optical trap moved in a stepwise manner in the direction of the actin filament only in the presence of ATP. At the trap strength of 0.3 pN/nm, the maximum size of the step was 11 nm, and the maximum force associated with the movement was 3.3 pN.
为阐明肌动球蛋白马达产生力的机制，构建了一个测量系统，该系统将体外运动分析与光镊技术相结合。将数微米长的肌动蛋白丝附着在凝溶胶蛋白包被的聚苯乙烯珠上，并使其与少量（约每1微米肌动蛋白丝1个）结合在硝酸纤维素包被的盖玻片上的兔骨骼肌重酶解肌球蛋白（肌球蛋白的活性亚片段）分子相互作用。以33毫秒的间隔确定珠子的位置。我们在相对较低（100 - 400 nM）的ATP浓度下测量力产生事件，以便能够以我们的时间分辨率检测到单个力产生事件。仅在ATP存在的情况下，被光镊捕获的与肌动蛋白结合的珠子沿肌动蛋白丝的方向以步进方式移动。在0.3 pN/nm的捕获强度下，步长的最大值为11 nm，与运动相关的最大力为3.3 pN。
Zotero 插件