Honda H, Kikuchi K, Hatori K, Imai E, Shimada K, Matsuno K
Department of BioEngineering, Nagaoka University of Technology, Nagaoka, 940-2188 Japan.
J Biol Phys. 2002 Sep;28(3):359-65. doi: 10.1023/A:1020304420132.
An actin filament sliding on myosin moleculesdemonstrates both longitudinal distortions and transversal fluctuationswith the linear dimension far exceeding the diameter of an actinmonomer. Local swaying of a single actin filament was identified byreading speckled fluorescent markers attached on the filament. Theaccuracy of reading each speckled marker was about 10.4 nm (r.m.s.).Longitudinal distortions of an actin filament at a low ATP concentrationof 20 μM were as much as 0.5 μm for the average filament lengthof 5.4 μm. The magnitude of transversal fluctuations was as much as60 nm, that was independent of the filament length. Both longitudinaldistortions and transversal fluctuations are suggested to play a pivotalrole for facilitating a smooth sliding movement of an actin filament.
肌动蛋白丝在肌球蛋白分子上滑动时，表现出纵向扭曲和横向波动，其线性尺寸远超过肌动蛋白单体的直径。通过读取附着在肌动蛋白丝上的斑点荧光标记物，识别出单根肌动蛋白丝的局部摆动。读取每个斑点标记物的精度约为10.4纳米（均方根）。在20μM的低ATP浓度下，对于平均长度为5.4μm的肌动蛋白丝，其纵向扭曲高达0.5μm。横向波动的幅度高达60纳米，且与丝的长度无关。纵向扭曲和横向波动都被认为在促进肌动蛋白丝的平滑滑动运动中起着关键作用。
