Maximum limit to the number of myosin II motors participating in processive sliding of actin
Maximum limit to the number of myosin II motors participating in processive sliding of actin
复制标题
参与肌动蛋白进行性滑动的肌球蛋白 II 马达数量的最大限制
作者：
K. Rastogi;Mohammed Shabeel Puliyakodan;V. Pandey;S. Nath;R. Elangovan
在这项工作中，我们分析了肌动蛋白丝在各种重肌球蛋白（HMM）密度和ATP浓度IVMA的进行性滑动和断裂。我们观察到，随着ATP溶液的加入，肌动蛋白丝随机断裂，然后我们确定断裂后存活的肌动蛋白丝的平均长度和速度。在恒定的ATP浓度下，平均细丝长度随HMM密度的增加而减小，在恒定的HMM密度下，平均细丝长度随ATP浓度的增加而增加。利用HMM分子的密度和肌动蛋白的长度，我们估计了每个肌动蛋白丝上参与肌动蛋白进行性滑动的HMM分子的数量（N）。N仅为ATP浓度的函数：88 ± 24和54 ± 22个HMM分子（平均值± S.D.）分别在2mM和0.1mM ATP下。只有当N处于HMM分子数的最小下限（Nmin）和最大上限（Nmax）范围内时，才观察到肌动蛋白丝的过程性滑动。当N-Nmax时，纤维最终断裂，不能继续进行滑动。< Nmin the actin filament diffused away from the surface and processivity was lost and when N >我们假设这个最大上限是由于强结合肌球蛋白头的数量增加而产生的。
In this work, we analysed processive sliding and breakage of actin filaments at various heavy meromyosin (HMM) densities and ATP concentrations in IVMA. We observed that with addition of ATP solution, the actin filaments fragmented stochastically; we then determined mean length and velocity of surviving actin filaments post breakage. Average filament length decreased with increase in HMM density at constant ATP and increased with increase in ATP concentration at constant HMM density. Using density of HMM molecules and length of actin, we estimated the number of HMM molecules per actin filament (N) that participate in processive sliding of actin. N is solely a function of ATP concentration: 88 ± 24 and 54 ± 22 HMM molecules (mean ± S.D.) at 2 mM and 0.1 mM ATP respectively. Processive sliding of actin filament was observed only when N lay within a minimum lower limit (Nmin) and a maximum upper limit (Nmax) to the number of HMM molecules. When N < Nmin the actin filament diffused away from the surface and processivity was lost and when N > Nmax the filament underwent breakage eventually and could not sustain processive sliding. We postulate this maximum upper limit arises due to increased number of strongly bound myosin heads.
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平滑肌肌球蛋白和骨骼肌肌球蛋白在体外零负荷下均表现出低占空比。
DOI：
--
发表时间：
1993
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Harris,DE;Warshaw,DM
通讯作者：
Warshaw,DM
DOI：
--
发表时间：
2012
期刊：
--
影响因子：
--
作者：
S. Walcott;D. Warshaw;E. Debold
通讯作者：
S. Walcott;D. Warshaw;E. Debold
影响因子：
4.8
作者：
Amrute-Nayak, Mamta;Antognozzi, Massimo;Brenner, Bernhard
通讯作者：
Brenner, Bernhard
DOI：
10.1073/pnas.83.17.6272
发表时间：
1986-09-01
影响因子：
11.1
作者：
KRON, SJ;SPUDICH, JA
通讯作者：
SPUDICH, JA