Toward Atomistic Resolution Structure of Phosphatidylcholine Headgroup and Glycerol Backbone at Different Ambient Conditions
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- 作者：Alexandru Botan ; Fernando Favela-Rosales ; Patrick F. J. Fuchs ; Matti Javanainen ; Matej Kandu膷 ; Waldemar Kulig ; Antti Lamberg ; Claire Loison ; Alexander Lyubartsev ; Markus S. Miettinen ; Luca Monticelli ; Jukka M盲盲tt盲 ; O. H. Samuli Ollila ; Marius Retegan ; Tomasz R贸g ; Hubert Santuz ; Joona Tynkkynen
- 刊名：Journal of Physical Chemistry B
- 出版年：2015
- 出版时间：December 10, 2015
- 年：2015
- 卷：119
- 期：49
- 页码：15075-15088
- 全文大小：906K
- ISSN：1520-5207
文摘
Phospholipids are essential building blocks of biological membranes. Despite a vast amount of very accurate experimental data, the atomistic resolution structures sampled by the glycerol backbone and choline headgroup in phoshatidylcholine bilayers are not known. Atomistic resolution molecular dynamics simulations have the potential to resolve the structures, and to give an arrestingly intuitive interpretation of the experimental data, but only if the simulations reproduce the data within experimental accuracy. In the present work, we simulated phosphatidylcholine (PC) lipid bilayers with 13 different atomistic models, and compared simulations with NMR experiments in terms of the highly structurally sensitive C鈥揌 bond vector order parameters. Focusing on the glycerol backbone and choline headgroups, we showed that the order parameter comparison can be used to judge the atomistic resolution structural accuracy of the models. Accurate models, in turn, allow molecular dynamics simulations to be used as an interpretation tool that translates these NMR data into a dynamic three-dimensional representation of biomolecules in biologically relevant conditions. In addition to lipid bilayers in fully hydrated conditions, we reviewed previous experimental data for dehydrated bilayers and cholesterol-containing bilayers, and interpreted them with simulations. Although none of the existing models reached experimental accuracy, by critically comparing them we were able to distill relevant chemical information: (1) increase of choline order parameters indicates the P鈥揘 vector tilting more parallel to the membrane, and (2) cholesterol induces only minor changes to the PC (glycerol backbone) structure. This work has been done as a fully open collaboration, using nmrlipids.blogspot.fi as a communication platform; all the scientific contributions were made publicly on this blog. During the open research process, the repository holding our simulation trajectories and files (https://zenodo.org/collection/user-nmrlipids) has become the most extensive publicly available collection of molecular dynamics simulation trajectories of lipid bilayers.