Calcium-mediated regulation of recombinant hybrids of full-length Physarum myosin heavy chain with Physarum/scallop myosin light chains.
Calcium-mediated regulation of recombinant hybrids of full-length Physarum myosin heavy chain with Physarum/scallop myosin light chains.
复制标题
全长绒泡菌肌球蛋白重链与绒泡菌/扇贝肌球蛋白轻链重组杂交体的钙介导调节。
DOI：
10.1093/abbs/gmw031
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
A.
中科院分区：
文献类型：
--
作者：
Zhang;Y.;Kawamichi;H.;Kohama;K.;and Nakamura;A.
Physarummyosin是一种Ca 2+结合蛋白，其活性受到Ca 2+的抑制。本研究以海蓬子和扇贝肌球蛋白轻链（LCs）为材料，构建了海蓬子肌球蛋白重链（Ph·HC）与海蓬子和/或扇贝肌球蛋白LCs的杂交体，研究了Ca ~（2+）对ATP酶和运动活动的调控。结果表明，Ca ~（2+）抑制了带有扇贝调节轻链（ScRLC）和海蓬子必需轻链（PhELC）的海蓬子杂交种肌球蛋白的运动和ATP酶活性，但不能抑制缺乏Ca ~（2+）结合能力的海蓬子杂交种突变体Ph·HC/ScRLC/PhELC-3A的运动和ATP酶活性，表明PhELC在Ca ~（2+）介导的海蓬子杂交种肌球蛋白的调节中起重要作用。Ca ~（2+）对肌球蛋白ATP酶活性的影响顺序为：Ph·HC/PhRLC/PhELC> Ph·HC/ScRLC/PhELC > Ph·HC/ScRLC/ScELC > Ph·HC/ScRLC/ScELC。虽然我们没有观察到Physarumhybrid肌球蛋白Ph·HC/PhRLC/ScELC和Ph·HC/ScRLC/ScELC的运动性，但我们的结果表明，Ca ~（2+）与PhELC的结合可能会改变调节结构域的灵活性，并诱导“闭合”状态，从而可能阻止完全的活动和力的产生。
Physarummyosin is a Ca2+-binding protein and its activity is inhibited by Ca2+. In the present study, to clarify the light chains (LCs) from the different species (Physarumand scallop) and to determine the specific Ca2+-regulated effects, we constructed hybrid myosins with aPhysarummyosin heavy chain (Ph·HC) andPhysarumand/or scallop myosin LCs, and examined Ca2+-mediated regulation of ATPases and motor activities. In these experiments, it was found that Ca2+inhibited motilities and ATPase activities ofPhysarumhybrid myosin with scallop regulatory light chain (ScRLC) andPhysarumessential light chain (PhELC) but could not inhibit those of thePhysarumhybrid myosin mutant Ph·HC/ScRLC/PhELC-3A which lacks Ca2+-binding ability, indicating that PhELC plays a critical role in Ca2+-mediated regulation ofPhysarummyosin. Furthermore, the effects of Ca2+on ATPase activities ofPhysarummyosin constructs are in the following order: Ph·HC/PhRLC/PhELC > Ph·HC/ScRLC/PhELC > Ph·HC/PhRLC/ScELC > Ph·HC/ScRLC/ScELC, suggesting that the presence of PhRLC and PhELC leads to the greatest Ca2+sensitivity ofPhysarummyosin. Although we did not observe the motilities ofPhysarumhybrid myosin Ph·HC/PhRLC/ScELC and Ph·HC/ScRLC/ScELC, our results suggest that Ca2+-binding to the PhELC may alter the flexibility of the regulatory domain and induce a ’closed’ state, which may consequently prevent full activity and force generation.