Minimal Model of Intrinsic Chirality to Study the Folding Behavior of Helical Polymers
Minimal Model of Intrinsic Chirality to Study the Folding Behavior of Helical Polymers
复制标题
DOI：
10.1021/ma500720t
复制
发表时间：
2014-09-09
期刊：
影响因子：
5.5
通讯作者：
Terentjev, Eugene M.
中科院分区：
文献类型：
--
作者：
Boehm, Christian R.;Terentjev, Eugene M.
我们描述了一个最小模型的固有手性聚合物链，并表征其在不同温度下的平衡和瞬态行为，并通过布朗动力学模拟的有效溶剂环境。与以前的研究相比，我们的模型透明地包括固有曲率和扭转作为残余固有（分子）手性的量度，以建立一个定义的手性，同时允许观察高温膨胀的无规线圈和密集的螺旋或球状状态之间的转换在低温下。在一般或良好的溶剂中，观察到折叠螺旋向无规卷曲的直接变性。在贫溶剂中，这一过程通过在低-中温范围内采用凝聚球而叠加。在这些条件下，我们发现，螺旋链代表亚稳态分离的结晶有利的致密球的能量障碍。最后，通过结合结构转变的观察与热容量的热力学异常的证据，我们认为螺旋球转变代表了一个不连续的相变过程。
We describe a minimal model of an intrinsically chiral polymer chain, and characterize its equilibrium and transient behavior at different temperatures, and in effective solvent environments by means of Brownian dynamics simulation. By contrast to previous studies, our model transparently includes intrinsic curvature and torsion as a measure of residue-inherent (molecular) chirality to establish a defined handedness, while allowing the observation of a transformation between a high-temperature expanded random coil and a dense helical or globular state at low temperatures. In fair or good solvents, a straightforward denaturation of a folded helix toward a random coil is observed. In poor solvent, this process is superimposed by adoption of a condensed globule in the low-medium temperature range. Under these conditions, we find that helical chains represent metastable states separated from the thermodynamically favored dense globule by an energy barrier. Finally, by combining the observations of structural transformations with the evidence of thermodynamic anomaly in the heat capacity, we suggest that the helixglobule transformation represents a discontinuous phase transition-like process.