Membrane properties of amacrocyclic tetraether bisphosphatidylcholine lipid: Effect of a single membrane-spanning polymethylene cross-linkage between two head groups of ditetradecylphosphatidylcholine membrane.

Affiliation

Tsuchida N(1), Takagi T(2), Takahashi H(3), Yoshihara T(1), Tobita S(1), Sonoyama M(4).
Author information:
(1)Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan.
(2)Cellular and Molecular Biotechnology Research Institute, AIST, Tsukuba, Ibaraki 305-8565, Japan. Electronic address: [Email]
(3)Division of Pure and Applied Science, Faculty of Science and Technology, Gunma University, Maebashi, Gunma 371-8510, Japan. Electronic address: [Email]
(4)Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan; Gunma University Initiative for Advanced Research
(GIAR), Gunma University, Kiryu, Gunma 376-8515, Japan; Gunma University Center for Food Science and Wellness
(GUCFW), Gunma University, Kiryu, Gunma 376-8515, Japan. Electronic address: [Email]

Abstract

The plasma membranes of archaea are abundant in macrocyclic tetraether lipids that contain a single or double long transmembrane hydrocarbon chains connecting the two glycerol backbones at both ends. In this study, a novel amacrocyclic bisphosphatidylcholine lipid bearing a single membrane-spanning octacosamethylene chain, 1,1'-O-octacosamethylene-2,2'-di-O-tetradecyl-bis-(sn-glycero)-3,3'-diphosphocholine (AC-(di-O-C14PC)2), was synthesized to elucidate effects of the interlayer cross-linkage on membrane properties based on comparison with its corresponding diether phosphatidylcholine, 1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (DTPC), that forms bilayer membrane. Several physicochemical techniques demonstrated that while AC-(di-O-C14PC)2 monolayer, which adopts a particularly high-ordered structure in the gel phase, shows remarkably high thermotropic transition temperature compared to DTPC bilayer, the fluidity of both phospholipids above the transition temperature is comparable. Nonetheless, the fluorescent dye leakage from inside the AC-(di-O-C14PC)2 vesicles in the fluid phase is highly suppressed. The origin of the membrane properties characteristic of AC-(di-O-C14PC)2 monolayer is discussed in terms of the single long transmembrane hydrophobic linkage and the diffusional motion of the lipid molecules.