中国物理B ›› 2017, Vol. 26 ›› Issue (4): 48701-048701.doi: 10.1088/1674-1056/26/4/048701

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

Combined effects of headgroup charge and tail unsaturation of lipids on lateral organization and diffusion of lipids in model biomembranes

Xiao-Jie Chen(陈晓洁), Qing Liang(梁清)   

  1. Center for Statistical and Theoretical Condensed Matter Physics and Department of Physics, Zhejiang Normal University, Jinhua 321004, China
  • 收稿日期:2016-10-16 修回日期:2016-12-10 出版日期:2017-04-05 发布日期:2017-04-05
  • 通讯作者: Qing Liang E-mail:qliang@zjnu.edu.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant No. 11674287) and China Scholarship Council.

Combined effects of headgroup charge and tail unsaturation of lipids on lateral organization and diffusion of lipids in model biomembranes

Xiao-Jie Chen(陈晓洁), Qing Liang(梁清)   

  1. Center for Statistical and Theoretical Condensed Matter Physics and Department of Physics, Zhejiang Normal University, Jinhua 321004, China
  • Received:2016-10-16 Revised:2016-12-10 Online:2017-04-05 Published:2017-04-05
  • Contact: Qing Liang E-mail:qliang@zjnu.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant No. 11674287) and China Scholarship Council.

摘要:

Lateral organization and dynamics of lipids in plasma membranes are crucial for several cellular processes such as signal transduction across the membrane and still remain elusive. In this paper, using coarse-grained molecular dynamics simulation, we theoretically study the combined effects of headgroup charge and tail unsaturation of lipids on the lateral organization and diffusion of lipids in ternary lipid bilayers. In neutral ternary lipid bilayers composed of saturated lipids, unsaturated lipids, and cholesterols, under the conditions of given temperature and components, the main factor for the phase separation is the unsaturation of unsaturated lipids and the bilayers can be separated into liquid-ordered domains enriched in saturated lipids and cholesterols and liquid-disordered domains enriched in unsaturated lipids. Once the headgroup charge is introduced, the electrostatic repulsion between the negatively charged lipid headgroups will increase the distance between the charged lipids. We find that the lateral organization and diffusion of the lipids in the (partially) charged ternary lipid bilayers are determined by the competition between the headgroup charge and the unsaturation of the unsaturated lipids. In the bilayers containing unsaturated lipids with lower unsaturation, the headgroup charge plays a crucial role in the lateral organization and diffusion of lipids. The headgroup charge may make the lipid domains unstable and even can suppress phase separation of the lipids in some systems. However, in the bilayers containing highly unsaturated lipids, the lateral organization and diffusion of lipids are mainly dominated by the unsaturation of the unsaturated lipids. This work may provide some theoretical insights into understanding the formation of nanosized domains and lateral diffusion of lipids in plasma membranes.

关键词: biomembrane, phase separation, molecular dynamics simulation, coarse grain

Abstract:

Lateral organization and dynamics of lipids in plasma membranes are crucial for several cellular processes such as signal transduction across the membrane and still remain elusive. In this paper, using coarse-grained molecular dynamics simulation, we theoretically study the combined effects of headgroup charge and tail unsaturation of lipids on the lateral organization and diffusion of lipids in ternary lipid bilayers. In neutral ternary lipid bilayers composed of saturated lipids, unsaturated lipids, and cholesterols, under the conditions of given temperature and components, the main factor for the phase separation is the unsaturation of unsaturated lipids and the bilayers can be separated into liquid-ordered domains enriched in saturated lipids and cholesterols and liquid-disordered domains enriched in unsaturated lipids. Once the headgroup charge is introduced, the electrostatic repulsion between the negatively charged lipid headgroups will increase the distance between the charged lipids. We find that the lateral organization and diffusion of the lipids in the (partially) charged ternary lipid bilayers are determined by the competition between the headgroup charge and the unsaturation of the unsaturated lipids. In the bilayers containing unsaturated lipids with lower unsaturation, the headgroup charge plays a crucial role in the lateral organization and diffusion of lipids. The headgroup charge may make the lipid domains unstable and even can suppress phase separation of the lipids in some systems. However, in the bilayers containing highly unsaturated lipids, the lateral organization and diffusion of lipids are mainly dominated by the unsaturation of the unsaturated lipids. This work may provide some theoretical insights into understanding the formation of nanosized domains and lateral diffusion of lipids in plasma membranes.

Key words: biomembrane, phase separation, molecular dynamics simulation, coarse grain

中图分类号:  (Membranes, bilayers, and vesicles)

  • 87.16.D-
87.15.A- (Theory, modeling, and computer simulation) 87.14.Cc (Lipids) 81.16.Dn (Self-assembly)