How sequence directs bending in tropomyosin and other two-stranded alpha-helical coiled coils
How sequence directs bending in tropomyosin and other two-stranded alpha-helical coiled coils
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DOI：
10.1002/pro.415
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发表时间：
2010-07-01
期刊：
影响因子：
8
通讯作者：
Brown, Jerry H.
中科院分区：
文献类型：
--
作者：
Brown, Jerry H.
已经进行了晶体结构中双链α-螺旋卷曲螺旋的弯曲方向的定量分析，以帮助确定卷曲螺旋的氨基酸序列如何影响其形状和功能。卷曲螺旋的轴向交错的变化，发生在原肌球蛋白中的核心丙氨酸簇或肌球蛋白棒中的核心庞大残基簇的边界处，导致局部二聚体平面内的弯曲。结果还表明，卷曲螺旋的核心中的大间隙，这是小核心残基附近的大核心残基或未分支的核心残基附近的典型分支的核心残基，与弯曲的本地二聚体平面。在独立晶体环境中确定的原肌球蛋白结构的比较为序列指导卷曲螺旋弯曲的概念提供了进一步的证据，但晶体环境至少与确定弯曲幅度的序列一样重要。因此，原肌球蛋白似乎包括更多的方向限制铰链样关节，而不是方向可变的万向关节，这有助于解释和预测其结合F-肌动蛋白的几何和动态性质。
A quantitative analysis of the direction of bending of two-stranded alpha-helical coiled coils in crystal structures has been carried out to help determine how the amino acid sequence of the coiled coil influences its shape and function. Change in the axial staggering of the coiled coil, occurring at the boundaries of either clusters of core alanines in tropomyosin or of clusters of core bulky residues in the myosin rod, causes bending within the plane of the local dimer. The results also reveal that large gaps in the core of the coiled coil, which are seen for small core residues near large core residues or for unbranched core residues near canonical branched core residues, are correlated with bending out of the local dimeric plane. Comparison of tropomyosin structures determined in independent crystal environments provides further evidence for the concept that sequence directs the bending of the coiled coil, but that crystal environment is at least as important as sequence for determining the magnitude of bending. Tropomyosin thus appears to consist of more directionally restrained hinge-like joints rather than directionally variable universal joints, which helps account for and predicts the geometric and dynamic nature of its binding to F-actin.