Hatori Kuniyuki, Matsui Masahiro, Omote Yoichiro
Department of Bio-System Engineering, Yamagata University, Jyonan, Yonezawa, Japan.
Biosystems. 2009 Apr;96(1):14-8. doi: 10.1016/j.biosystems.2008.11.003. Epub 2008 Nov 18.
An actin filament sliding on myosin molecules exhibits fluctuating or staggered movements as responding to changes in the ATP concentration. We previously observed that fluctuations in the sliding velocity enhanced in a manner being independent of the magnitude of the velocity. The present study focused upon a single actin filament bound to a glass surface through avidin-biotin bonding to examine those fluctuations inherent to the filament in the presence of heavy meromyosin. The auto-correlation analysis revealed that the relaxation time of fluctuations in the filamental displacement obtains its maximum value at about 100microM of the ATP concentration in the ambient, while the magnitude of the fluctuations gradually increased with an increase of the concentration. Furthermore, the measurement of the fluorescence intensity from the markers fixed on the filament demonstrated an enhancement of the negative correlation between the measured peak intensity and the spatial spreading of its intensity over the range of 0-200microM of the ATP concentration, as indicating both development and mitigation of local distortions occurring within the filament.
肌动蛋白丝在肌球蛋白分子上滑动时，会随着ATP浓度的变化呈现出波动或交错运动。我们之前观察到，滑动速度的波动增强，且这种增强方式与速度大小无关。本研究聚焦于通过抗生物素蛋白-生物素键合固定在玻璃表面的单根肌动蛋白丝，以研究在存在重酶解肌球蛋白的情况下该丝自身固有的那些波动。自相关分析表明，在环境中ATP浓度约为100微摩尔时，丝状位移波动的弛豫时间达到最大值，而波动幅度则随着浓度的增加而逐渐增大。此外，对固定在丝上的标记物的荧光强度测量表明，在0至200微摩尔的ATP浓度范围内，测量到的峰值强度与其强度的空间扩展之间的负相关性增强，这表明丝内发生的局部变形既有发展也有缓解。
