Geometrical effects of phospholipid olefinic bonds on the structure and dynamics of membranes: A molecular dynamics study.
The trans isomers of fatty acids are found in human adipose tissue. These isomers have been linked with deleterious health effects (e.g., coronary artery disease). In this study, we performed molecular dynamics simulations to investigate the structures and dynamic properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) and 1-palmitoyl-2-elaidoyl sn-glycero-3-phosphatidylcholine (PEPC) lipid bilayers. The geometry of the olefinic bond and membrane packing effects significantly influenced the conformations and dynamics of the two C-C single bonds adjacent to the olefinic bond. For the PEPC lipid, the two C-C single bonds adjacent to the olefinic bond adopted mainly nonplanar skew-trans and planar cis-trans motifs; although the cis conformation featured relatively strong steric repulsion, it was stabilized through membrane packing because its planar structure is more suitable for membrane packing. Moreover, membrane packing effects stabilized the planar transition state for conformational conversion to a greater extent than they did with the nonplanar transition state, thereby affecting the dynamics of conformational conversion. The rotational motions of the first neighboring C-C single bonds were much faster than those of typical saturated C-C single bonds; in contrast, the rotational motions of the second neighboring C-C single bonds were significantly slower than those of typical saturated torsion angles. The packing of PEPC lipids is superior to that of POPC lipids, leading to a smaller area per lipid, a higher order parameter and a smaller diffusion coefficient. The distinct properties of POPC and PEPC lipids result in PEPC lipids forming microdomains within a POPC matrix.
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan. Electronic address: hhtsai@cc.ncu.edu.tw.
Hui-Hsu Gavin
HH
Tsai
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan.
Jian-Bin
JB
Lee
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan.
Hung-Sheng
HS
Li
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan.
Tsai-Yi
TY
Hou
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan.
Wen-Yuan
WY
Chu
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan.
Po-Chuan
PC
Shen
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan.
Ying-Yu
YY
Chen
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan.
Chun-Jui
CJ
Tan
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan.
Jia-Cheng
JC
Hu
Department of Chemistry, National Central University, Jhong-Li City, Tao-Yuan County 32001, Taiwan.
Chih-Chiang
CC
Chiu
D000215:Acylation; D004058:Diffusion; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D008051:Lipid Bilayers; D021962:Membrane Microdomains / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D009829:Oleic Acids / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*; D055672:Static Electricity; D013329:Structure-Activity Relationship
C434585:1-palmitoyl-2-elaidoylphosphatidylcholine; D008051:Lipid Bilayers; D009829:Oleic Acids; D010713:Phosphatidylcholines; C028694:1-palmitoyl-2-oleoylphosphatidylcholine; D004134:Dimyristoylphosphatidylcholine
Geometrical effect of olefinic bond; Membrane packing effect; Micro-domain; Trans-phospholipid