Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang 310024, China.
Westlake Laboratory of Life Sciences and Biomedicine, 18 Shilongshan Road, Hangzhou, Zhejiang 310024, China.
J Phys Chem B. 2021 Jan 14;125(1):393-405. doi: 10.1021/acs.jpcb.0c08556. Epub 2020 Dec 29.
Methylguanidinium is an important molecular ion, which also serves as the model compound for the arginine side chain. We studied the structure and dynamics of the methylguanidium ion at the air/water interface by molecular dynamics simulations employing the Drude polarizable force field. We found out that methylguanidinium accumulated at the interface, with a majority adopting tilted conformations. We also demonstrated that methylguanidinium and guanidinium ions had different preference toward the air/water interface. Detailed analysis of induced dipole moments showed how ions adjusted their charge distribution at the interface and revealed how the anisotropy in molecular polarizability impacted the orientation of molecular ions. Our results illustrate the importance of explicitly including the electronic polarization effects in modeling interfacial properties.
甲基胍鎓是一种重要的分子离子，也是精氨酸侧链的模型化合物。我们通过采用 Drude 极化力场的分子动力学模拟研究了甲基胍鎓离子在气/水界面的结构和动力学。我们发现甲基胍鎓离子在界面上聚集，大多数采用倾斜构象。我们还证明了甲基胍鎓离子和胍鎓离子对气/水界面的偏好不同。诱导偶极矩的详细分析表明了离子如何在界面上调整其电荷分布，并揭示了分子极化率的各向异性如何影响分子离子的取向。我们的结果说明了在建模界面性质时明确包含电子极化效应的重要性。
