X-ray diffraction from nonuniformly stretched helical molecules.
X-ray diffraction from nonuniformly stretched helical molecules.
复制标题
非均匀拉伸螺旋分子的 X 射线衍射。
DOI：
10.1107/s1600576716003757
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发表时间：
2016
影响因子：
6.1
通讯作者：
Mijailovich,SrboljubM
中科院分区：
文献类型：
--
作者：
Prodanovic,Momcilo;Irving,ThomasC;Mijailovich,SrboljubM
活细胞中的纤维蛋白质暴露于与其他亚细胞结构相互作用的机械力。X射线纤维衍射通常用于评估这些蛋白质的变形和运动，但分析仅限于表现出螺旋对称性的纤维分子系统的理论。然而，这种方法不能充分解释X-射线数据的纤维蛋白质组件的局部应变变化沿着纤维长度由于其分子成分与它们的结合伙伴的相互作用。为了解决这个问题，我们提出了一个理论公式，用来预测单个螺旋分子结构在沿其长度方向非均匀沿着应变时的衍射。这是一个关键的第一步，对复杂的动力学系统建模的多个螺旋结构，使用空间上明确的，多尺度的蒙特卡罗模拟，预测与实验数据进行比较，在一个“向前”的过程中，迭代生成更现实的模型。在这里，不均匀的应变和螺旋长度上产生的衍射图案的幅度和相位的影响进行了定量评估。在收缩肌肉的非均匀变形的双链DNA和肌动蛋白丝的预测衍射图案的例子来证明这种理论方法的可行性。
The fibrous proteins in living cells are exposed to mechanical forces interacting with other subcellular structures. X-ray fiber diffraction is often used to assess deformation and movement of these proteins, but the analysis has been limited to the theory for fibrous molecular systems that exhibit helical symmetry. However, this approach cannot adequately interpret X-ray data from fibrous protein assemblies where the local strain varies along the fiber length owing to interactions of its molecular constituents with their binding partners. To resolve this problem a theoretical formulism has been developed for predicting the diffraction from individual helical molecular structures nonuniformly strained along their lengths. This represents a critical first step towards modeling complex dynamical systems consisting of multiple helical structures using spatially explicit, multi-scale Monte Carlo simulations where predictions are compared with experimental data in a `forward' process to iteratively generate ever more realistic models. Here the effects of nonuniform strains and the helix length on the resulting magnitude and phase of diffraction patterns are quantitatively assessed. Examples of the predicted diffraction patterns of nonuniformly deformed double-stranded DNA and actin filaments in contracting muscle are presented to demonstrate the feasibly of this theoretical approach.