Hudek Magdalena, Kubiak-Ossowska Karina, Johnston Karen, Ferro Valerie A, Mulheran Paul A
Department of Chemical and Process Engineering, University of Strathclyde, 75 Montrose Street, GlasgowG1 1XJ, Scotland.
ARCHIE-WeSt, Department of Physics, University of Strathclyde, 107 Rottenrow East, GlasgowG4 0NG, Scotland.
ACS Omega. 2023 Jan 10;8(3):3470-3477. doi: 10.1021/acsomega.2c07495. eCollection 2023 Jan 24.
Understanding the binding of chitosan oligomers to the surface of a chitin nanocrystal is important for improving the enzymatic deacetylation of chitin and for the design of chitin/chitosan composite films. Here, we study the binding of several chito-oligomers to the (100) surface of an α-chitin crystal using molecular dynamics (MD), steered MD, and umbrella sampling. The convergence of the free energy was carefully considered and yielded a binding energies of -12.5 and -2 kcal mol for 6-monomer-long chitin and uncharged chitosan oligomers, respectively. We also found that the results for the umbrella sampling were consistent with the force profile from the steered MD and with classical MD simulations of the adsorption process. Our results give insight into the molecular-scale interactions, which can be helpful for the design of new chitin composite films. Furthermore, the free energy curves we present can be used to validate coarse-grained models for chitin and chitosan, which are necessary to study the self-assembly of chitin crystals due to the long time scale of the process.
了解壳聚糖低聚物与几丁质纳米晶体表面的结合情况，对于改善几丁质的酶促脱乙酰作用以及几丁质/壳聚糖复合膜的设计至关重要。在此，我们使用分子动力学（MD）、引导分子动力学和伞形采样研究了几种壳寡聚物与α-几丁质晶体（100）表面的结合。仔细考虑了自由能的收敛情况，对于6个单体长的几丁质和不带电荷的壳聚糖低聚物，得到的结合能分别为-12.5和-2千卡/摩尔。我们还发现，伞形采样的结果与引导分子动力学的力分布以及吸附过程的经典分子动力学模拟结果一致。我们的结果深入揭示了分子尺度的相互作用，这有助于新型几丁质复合膜的设计。此外，我们给出的自由能曲线可用于验证几丁质和壳聚糖的粗粒度模型，由于该过程的时间尺度较长，这些模型对于研究几丁质晶体的自组装是必要的。
