Dynamic modulation of the regulatory domain of myosin heads by pH, ionic strength, and RLC phosphorylation in synthetic myosin filaments.
Dynamic modulation of the regulatory domain of myosin heads by pH, ionic strength, and RLC phosphorylation in synthetic myosin filaments.
复制标题
通过合成肌球蛋白丝中的 pH、离子强度和 RLC 磷酸化动态调节肌球蛋白头的调节域。
DOI：
10.1021/bi982553g
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Fajer,PG
中科院分区：
文献类型：
--
作者：
Adhikari,BB;Somerset,J;Stull,JT;Fajer,PG
肌球蛋白头部相对于肌丝骨架的位置被认为是pH、离子强度（μ）和调节轻链（RLC）磷酸化程度的函数[哈灵顿（1979）美国国家科学院院刊（Proc. Natl. Chem. Acad. Sci. U.S.A. 76，5066 - 5070]。本研究的目的是检查肌球蛋白头部（调节域）的近端部分的动态，伴随着头部处置的变化。用茚二酮自旋标记物在Cys 177处标记必需轻链，然后将标记的蛋白质交换成肌球蛋白。饱和转移电子顺磁共振研究重组，合成肌球蛋白丝的标记结构域的流动性。我们已经发现，释放的头从肌球蛋白丝表面的静电荷的减少是伴随着2倍的增加，在流动性的监管结构域。RLC通过肌球蛋白轻链激酶的磷酸化导致运动的较小的1.5倍增加，确立了通过电子显微镜观察到的头部紊乱[Levine等人（1996）Biophys. J. 71，898 - 907]是由于头部的移动性增加。这一结果间接支持了这一假设，即RLC磷酸化的增强力的影响产生的头从丝表面的释放和转向肌动蛋白的头部。
The position of the myosin head with respect to the filament backbone is thought to be a function of pH, ionic strength (μ) and the extent of regulatory light chain (RLC) phosphorylation [Harrington (1979)Proc. Natl. Acad. Sci. U.S.A. 76, 5066−5070]. The object of this study is to examine the dynamics of the proximal part of the myosin head (regulatory domain) which accompany the changes in head disposition. The essential light chain was labeled at Cys177 with the indanedione spin-label followed by the exchange of the labeled proteins into myosin. The mobility of the labeled domain was investigated with saturation transfer electron paramagnetic resonance in reconstituted, synthetic myosin filaments. We have found that the release of the heads from the myosin filament surface by reduction of electrostatic charge is accompanied by a 2-fold increase in the mobility of the regulatory domain. Phosphorylation of the RLC by myosin light chain kinase resulted in a smaller 1.5-fold increase of motion, establishing that the head disordering observed by electron microscopy [Levine et al. (1996)Biophys. J. 71, 898−907] is due to increased mobility of the heads. This result indirectly supports the hypothesis that the RLC phosphorylation effect on potentiation of force arises from a release of heads from the filament surface and a shift of the heads toward actin.
影响因子：
64.8
作者：
M. Geeves;K. Holmes;M. Geeves
通讯作者：
M. Geeves