Deringer Volker L, Englert Ulli, Dronskowski Richard
Institute of Inorganic Chemistry and ‡Jülich-Aachen Research Alliance (JARA-HPC), RWTH Aachen University , Landoltweg 1, 52056 Aachen, Germany.
Biomacromolecules. 2016 Mar 14;17(3):996-1003. doi: 10.1021/acs.biomac.5b01653. Epub 2016 Feb 11.
Chitin is an abundant biopolymer that stabilizes the exoskeleton of insects and gives structure to plants. Its macroscopic properties go back to an intricate network of hydrogen bonds that connect the polymer strands, and these intermolecular links have been under ongoing study. Here, we use atomistic simulations to explore hydrogen bonding in the most abundant form, α-chitin. The crystal structure exhibits disorder, and so discrete models are systematically derived as suitable approximants to the macroscopic material. These models then allow us to perform dispersion-corrected density-functional theory (DFT-D) simulations on the three-dimensional crystal network and on lower-dimensional fragments. Thereby, we rationalize the nature of hydrogen bonding and the role of crystallographic disorder for the stability of α-chitin, and complement previous, larger-scale molecular-dynamics (MD) simulations as well as recent fiber-diffraction experiments. Our results provide new, atomic-level insight into one of Nature's most abundant building materials, and the techniques and concepts are likely transferable to other biopolymers.
几丁质是一种丰富的生物聚合物，它稳定昆虫的外骨骼并赋予植物结构。其宏观性质可追溯到连接聚合物链的复杂氢键网络，并且这些分子间连接一直在研究中。在这里，我们使用原子模拟来探索最丰富形式的α-几丁质中的氢键。晶体结构表现出无序性，因此离散模型被系统地推导为宏观材料的合适近似物。这些模型然后使我们能够在三维晶体网络和低维片段上进行色散校正密度泛函理论（DFT-D）模拟。由此，我们阐明了氢键的本质以及晶体学无序对α-几丁质稳定性的作用，并补充了先前的大规模分子动力学（MD）模拟以及最近的纤维衍射实验。我们的结果为自然界中最丰富的建筑材料之一提供了新的原子水平见解，并且这些技术和概念可能可转移到其他生物聚合物。
