Electric field-induced orientation of L- and DL-phosphatidylcholine bilayers.
Membrane orientation induced by an alternating electric field has been examined for the L-enantiomer and racemic dipalmitoylphosphatidylcholine (DPPC) bilayers. The orientation effect was measured by bending curvature of hairpin-like deformation of the multilamellar cylindrical tubes with varying field-strength, frequency and tube size. It has been observed that both L- and DL-DPPC tubes are similar in the profiles of field-strength dependence and frequency dependence on the curvature deformation, but different in the deformed curvatures. DL-DPPC tubes deform largely as compared with L-DPPC tubes. The square of the deformed curvature of DL-DPPC tubes is larger than that of L-DPPC by about 37% on average. The result indicates that the racemic membrane is responsive to the electric field as compared with the L-enantiomer membrane. This suggests that a hybrid arrangement of head groups of the racemic lipid leads an effective response of the membrane due to the head group orientation.
Mishima
Kiyoshi
K
Department of Physics, College of Arts and Sciences, Showa University, 4562 Kamiyoshida, Yamanashi 4030005, Fujiyoshida, Japan. mishima@cas.showa-u.ac.jp
Tanaka
Shinobu
S
Ogihara
Toshihiko
T
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D004574:Electromagnetic Fields; D008051:Lipid Bilayers / Q000737:chemistry*; D008968:Molecular Conformation; D010713:Phosphatidylcholines / Q000737:chemistry*; D013237:Stereoisomerism
D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D015060:1,2-Dipalmitoylphosphatidylcholine