TY - JOUR
T1 - Direct evidence of induction of interdigitated gel structure in large unilamellar vesicles of dipalmitoylphosphatidylcholine by ethanol
T2 - studies by excimer method and high-resolution electron cryomicroscopy
AU - Yamazaki, M.
AU - Miyazu, M.
AU - Asano, T.
AU - Yuba, A.
AU - Kume, N.
N1 - Funding Information:
We thank Dr. Y. Fujiyoshi of Protein Engineering Research Institute for valuable advice, Prof. H. Yamagishi of Kyoto University for constant en- couragement, and Prof. H. Hashizume of Shizuoka University for use of a Hitachi F3000 spectrofluorimeter. We thank N. Takahashi of Kyoto Uni- versity for technical assistance. This work was partly supported by Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan (to M. Y.) and the Research Promotion Grants for Young scientists from Shizuoka University (to M. Y.).
PY - 1994
Y1 - 1994
N2 - Interaction of large unilamellar vesicle (LUV) of dipalmitoylphosphatidylcholine (DPPC) with ethanol was investigated by the excimer method developed by Yamazaki et al. (Yamazaki, M., M. Miyazu, and T. Asano. 1992. Biochim. Biophys. Acta. 1106:94–98) and the high-resolution electron cryomicroscope with a new cryostage (top-entry superfluid stage) (HiRECM) developed by Fujiyoshi, Y. et al. (Fujiyoshi, Y., T. Mizusaki, K. Morikawa, H. Aoki, H. Kihara, and Y. Harada. 1991. Ultramicroscopy. 38:241–251). The excimer method is based on the fact that the ratio of excimer to monomer fluorescence intensity (E/M) of pyrene PC is lowered in the membrane in the interdigitated gel structure (L beta I), because structural restriction of L beta I structure largely decreases collisions of pyrene rings of the pyrene PCs in the membrane. E/M of pyrene PC in DPPC LUV decreased largely at high concentrations of ethanol, which indicated the induction of L beta I structures in DPPC LUV. Frozen-hydrated DPPC LUVs in a vitreous ice were observed at 4K with HiRECM, and these images were characterized by a pair of concentric circles. The membrane thickness of DPPC LUV which was estimated from the distance between the two concentric lines decreased largely at high concentration of ethanol. The mean value of membrane thickness of the LUV in the absence of ethanol was 3.8 nm, while at 15% (w/v) ethanol was 3.0 nm. These values were almost same as those obtained from the electron density profile of DPPC MLV by the x-ray diffraction analysis in each structures, L beta' and L beta I structures, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
AB - Interaction of large unilamellar vesicle (LUV) of dipalmitoylphosphatidylcholine (DPPC) with ethanol was investigated by the excimer method developed by Yamazaki et al. (Yamazaki, M., M. Miyazu, and T. Asano. 1992. Biochim. Biophys. Acta. 1106:94–98) and the high-resolution electron cryomicroscope with a new cryostage (top-entry superfluid stage) (HiRECM) developed by Fujiyoshi, Y. et al. (Fujiyoshi, Y., T. Mizusaki, K. Morikawa, H. Aoki, H. Kihara, and Y. Harada. 1991. Ultramicroscopy. 38:241–251). The excimer method is based on the fact that the ratio of excimer to monomer fluorescence intensity (E/M) of pyrene PC is lowered in the membrane in the interdigitated gel structure (L beta I), because structural restriction of L beta I structure largely decreases collisions of pyrene rings of the pyrene PCs in the membrane. E/M of pyrene PC in DPPC LUV decreased largely at high concentrations of ethanol, which indicated the induction of L beta I structures in DPPC LUV. Frozen-hydrated DPPC LUVs in a vitreous ice were observed at 4K with HiRECM, and these images were characterized by a pair of concentric circles. The membrane thickness of DPPC LUV which was estimated from the distance between the two concentric lines decreased largely at high concentration of ethanol. The mean value of membrane thickness of the LUV in the absence of ethanol was 3.8 nm, while at 15% (w/v) ethanol was 3.0 nm. These values were almost same as those obtained from the electron density profile of DPPC MLV by the x-ray diffraction analysis in each structures, L beta' and L beta I structures, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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U2 - 10.1016/S0006-3495(94)80848-3
DO - 10.1016/S0006-3495(94)80848-3
M3 - Article
C2 - 8011904
AN - SCOPUS:0028324639
SN - 0006-3495
VL - 66
SP - 729
EP - 733
JO - Biophysical Journal
JF - Biophysical Journal
IS - 3
ER -