DIRECT MEASUREMENT OF STIFFNESS OF SINGLE ACTIN-FILAMENTS WITH AND WITHOUT TROPOMYOSIN BY IN-VITRO NANOMANIPULATION
DIRECT MEASUREMENT OF STIFFNESS OF SINGLE ACTIN-FILAMENTS WITH AND WITHOUT TROPOMYOSIN BY IN-VITRO NANOMANIPULATION
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DOI：
10.1073/pnas.91.26.12962
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发表时间：
1994-12-20
影响因子：
11.1
通讯作者：
YANAGIDA, T
中科院分区：
文献类型：
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作者：
KOJIMA, H;ISHIJIMA, A;YANAGIDA, T
为了从分子水平解释肌肉收缩的机制，了解活动肌肉肌节顺应性的分布是至关重要的。在这里，我们直接测量单肌动蛋白丝的刚度与原肌球蛋白，使用最近开发的技术与微针的单肌动蛋白丝的纳米操纵。结果表明，含和不含原肌球蛋白的1 μ m长的肌动蛋白丝的刚度分别为65.3 ± 6.3和43.7 ± 4.6 pN/nm。当考虑到跨桥力沿着肌动蛋白丝的分布时，计算出1 μ m长的细丝在等长收缩过程中的伸长约为0.23%。响应于突然长度变化的力的时间常数为
In order to explain the molecular mechanism of muscle contraction, it is crucial to know the distribution of the sarcomere compliance of active muscle. Here, we directly measure the stiffness of single actin filaments with and without tropomyosin, using a recently developed technique for nanomanipulation of single actin filaments with microneedles. The results show that the stiffness for 1-mu m-long actin filaments with and without tropomyosin is 65.3 +/- 6.3 and 43.7 +/- 4.6 pN/nm, respectively, When the distribution of crossbridge forces along the actin filament is taken into account, the elongation of a 1-mu m-long thin filament during development of isometric contraction is calculated to be approximate to 0.23%. The time constant of force in response to a sudden length change is