利用离心显微镜的力-运动检测系统揭示的ATP依赖的肌动蛋白-肌球蛋白滑动的动力学特性。
Kinetic properties of the ATP-dependent actin-myosin sliding as revealed by the force-movement assay system with a centrifuge microscope.
作者信息
Chaen S, Oiwa K, Kobayashi T, Gross T, Kamitsubo E, Shimmen 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;332:351-9; discussion 360. doi: 10.1007/978-1-4615-2872-2_34.
To study the kinetic properties of the ATP-dependent actin-myosin sliding responsible for muscle contraction, we developed an in vitro force-movement assay system, in which centrifugal forces were applied to myosin-coated polystyrene beads sliding along actin cables of giant algal cells in the presence of ATP. Under constant centrifugal forces directed opposite to the bead movement ("positive" loads), the beads moved with constant velocities. The steady-state force-velocity (P-V) curve thus obtained was double-hyperbolic in shape, being analogous to the P-V curve of single muscle fibers. Under constant centrifugal forces in the direction of the bead movement ("negative" loads), on the other hand, the beads also moved with constant velocities. Unexpectedly, the velocity of bead movement did not increase with increasing negative loads, but decreased markedly (by 20-60%). We also studied the effect of centrifugal forces at right angles with actin cables on the bead movement.
为了研究负责肌肉收缩的ATP依赖性肌动蛋白-肌球蛋白滑动的动力学特性，我们开发了一种体外力-运动测定系统，在该系统中，在ATP存在的情况下，将离心力施加于沿着巨型藻类细胞的肌动蛋白丝滑动的包被有肌球蛋白的聚苯乙烯珠上。在与珠运动方向相反的恒定离心力（“正”负荷）作用下，珠以恒定速度移动。由此获得的稳态力-速度（P-V）曲线呈双双曲线形状，类似于单根肌纤维的P-V曲线。另一方面，在与珠运动方向相同的恒定离心力（“负”负荷）作用下，珠也以恒定速度移动。出乎意料的是，珠的运动速度并未随着负负荷的增加而增加，而是显著降低（降低了20%-60%）。我们还研究了与肌动蛋白丝成直角的离心力对珠运动的影响。
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