A vertebrate myosin-I structure reveals unique insights into myosin mechanochemical tuning.
A vertebrate myosin-I structure reveals unique insights into myosin mechanochemical tuning.
复制标题
脊椎动物肌球蛋白-I 结构揭示了对肌球蛋白机械化学调节的独特见解。
DOI：
10.1073/pnas.1321022111
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发表时间：
2014
影响因子：
11.1
通讯作者：
Ostap,EMichael
中科院分区：
文献类型：
--
作者：
Shuman,Henry;Greenberg,MichaelJ;Zwolak,Adam;Lin,Tianming;Sindelar,CharlesV;Dominguez,Roberto;Ostap,EMichael
肌球蛋白是驱动多种细胞过程的分子马达，例如快速细胞器运输、肌肉收缩和张力敏感锚定。允许这种功能多样性的电机结构适应尚不清楚，部分原因是缺乏高分辨率结构的高度张力敏感肌球蛋白。我们确定了一个2.3的apo-myosin-Ib（Myo1b），这是最张力敏感的肌球蛋白的特点，分辨率结构。我们发现了一个独特的结构元件定位马达的杠杆臂，这个方向导致马达和杠杆臂之间有一个空腔，容纳了一段10个残基的N-末端氨基酸，这是一个肌球蛋白不同的区域。单分子和生物化学分析表明，N末端在稳定后的Power-stroke构象的Myo1b，并在调整的力敏转换率中起着重要的作用。我们建议，这一地区发挥了普遍的作用，在调整肌球蛋白的机械化学性质。
Myosins are molecular motors that power diverse cellular processes, such as rapid organelle transport, muscle contraction, and tension-sensitive anchoring. The structural adaptations in the motor that allow for this functional diversity are not known, due, in part, to the lack of high-resolution structures of highly tension-sensitive myosins. We determined a 2.3-Å resolution structure of apo-myosin-Ib (Myo1b), which is the most tension-sensitive myosin characterized. We identified a striking unique orientation of structural elements that position the motor’s lever arm. This orientation results in a cavity between the motor and lever arm that holds a 10-residue stretch of N-terminal amino acids, a region that is divergent among myosins. Single-molecule and biochemical analyses show that the N terminus plays an important role in stabilizing the post power-stroke conformation of Myo1b and in tuning the rate of the force-sensitive transition. We propose that this region plays a general role in tuning the mechanochemical properties of myosins.