Quantum Chemical Study of Carbohydrate鈥揚hospholipid Interactions
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- 作者：R. Parthasarathi ; Jianhui Tian ; Antonio Redondo ; S. Gnanakaran
- 刊名：Journal of Physical Chemistry A
- 出版年：2011
- 出版时间：November 17, 2011
- 年：2011
- 卷：115
- 期：45
- 页码：12826-12840
- 全文大小：1322K
- 年卷期：v.115,no.45(November 17, 2011)
- ISSN：1520-5215
文摘
Carbohydrates on host membranes are fundamental to many important biological processes. Here, we seek a basic understanding of the nature of the interactions between carbohydrates and phospholipids to dissect their roles in molecular recognition. A hybrid quantum mechanics/quantum mechanics (QM/QM) scheme with two different levels of treatment was used to explore the conformations and energetics of carbohydrate鈥損hospholipid complexes. We investigate the interactions of two phospholipids (POPC and DOPC) with mannose using density functional theory. Carbohydrate鈥損hospholipid interactions are probed with respect to competing interactions with water. Our hybrid QM/QM approach demonstrates that mannose interactions with phospholipids can result in alterations in charge distributions and conformations of phospholipids. The results clearly reveal the interplay between conventional and nonconventional hydrogen bonding; moreover, nonpolar interactions are shown to be crucial in the recognition and further stabilization of carbohydrate鈥損hospholipid complexes. The influence of the acyl chain on phospholipid headgroup orientation is clearly evident in our investigation. The significance of the conventional OH路路路O and nonconventional CH路路路O and CH路路路C interactions in the stabilization of the intermolecular complexes is deduced from the molecular electron density topology using Bader鈥檚 atoms-in-molecules theory. Finally, we have compared the QM energies with molecular mechanics energies for the same interactions to aid in the refinement of the all-atom lipid鈥揷arbohydrate force fields.