A Tunable, Particle-Based Model for the Diverse Conformations Exhibited by Chiral Homopolymers
A Tunable, Particle-Based Model for the Diverse Conformations Exhibited by Chiral Homopolymers
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针对手性均聚物表现出的多种构象的可调谐、基于粒子的模型
DOI：
10.1021/acs.macromol.2c00613
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发表时间：
2022
期刊：
影响因子：
5.5
通讯作者：
Padmanabhan, Poornima
中科院分区：
文献类型：
--
作者：
Buchanan, Natalie;Provenzano, Joules;Padmanabhan, Poornima
能够分层自组装的手性嵌段共聚物还可以表现出手性转移——单体或构象尺度的手性转移到自组装。先前的研究主要集中在实验和理论方法上，这些方法无法完全解耦手性传递的热力学起源，因此需要开发基于粒子的模型来量化链内、链间和熵的贡献。考虑到这一目标，在这项工作中，我们开发了手性均聚物的参数化粗粒度模型，并广泛表征了所得构象。具体来说，角势和二面角势能、角设定点和二面角设定点中的能量参数系统地变化，以产生从随机卷曲到近乎理想的螺旋的各种构象。测量平均螺旋度、螺距、持续长度和端到端距离，并获得模型参数和所得构象之间的相关性。使用基于类肽的手性聚合物模型的可用实验数据，我们取消了产生实验中报告的类似螺距和持久长度比所需的参数。实验匹配的链的构象似乎有些柔性，表现出一些螺旋转弯。我们的模型用途广泛，可用于对手性嵌段共聚物甚至序列特异性多肽进行分子动力学模拟，以研究它们的自组装并获得热力学见解。
Chiral block copolymers capable of hierarchical self-assembly can also exhibit chirality transfer─the transfer of chirality at the monomer or conformational scale to the self-assembly. Prior studies focused on experimental and theoretical methods that are unable to fully decouple the thermodynamic origins of chirality transfer and necessitate the development of particle-based models that can be used to quantify intrachain, interchain, and entropic contributions. With this goal in mind, in this work, we developed a parametrized coarse-grained model of a chiral homopolymer and extensively characterized the resulting conformations. Specifically, the energetic parameter in the angular and dihedral potentials, the angular set point, and the dihedral set point are systematically varied to produce a wide range of conformations from a random coil to a nearly ideal helix. The average helicity, pitch, persistence length, and end-to-end distance are measured, and correlations between the model parameters and resulting conformations are obtained. Using available experimental data on model polypeptoid-based chiral polymers, we back out the required parameters that produce similar pitch and persistence length ratios reported in the experiments. The conformations for the experimentally matched chains appear to be somewhat flexible, exhibiting some helical turns. Our model is versatile and can be used to perform molecular dynamics simulations of chiral block copolymers and even sequence-specific polypeptides to study their self-assembly and to gain thermodynamic insights.
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影响因子：
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作者：
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发表时间：
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影响因子：
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