Abstract
The temperature-composition phase diagram of monomyristolein in water was constructed using x-ray diffraction. Low- and wide-angle diffraction patterns were collected from samples of fixed hydration as a function of temperature in the heating direction on x-ray-sensitive film and/or image plates. The phases identified in the system include the lamellar crystalline phase, the lamellar liquid crystalline phase, the fluid isotropic phase, and two inverted cubic phases. Particular attention has been devoted to the issues of phase equilibrium and phase boundary verification. Cubic phase undercooling was examined by adjusting the temperature of several samples in the cubic phase to a value where the lamellar liquid crystalline phase represents equilibrium behavior. Cooling-induced structure and phase changes were monitored continuously over a 30-min period by recording low-angle diffraction patterns from the samples using a streak camera. The cubic-to-lamellar transition rate decreased with increasing sample hydration. Additionally, the transition proceeded more rapidly at an incubation temperature of 25 degrees C compared to that at 0 degrees C. A mechanism is proposed that accounts for the hydration and temperature sensitivity of the phase transition under nonequilibrium conditions.
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- Caffrey M. Kinetics and mechanism of transitions involving the lamellar, cubic, inverted hexagonal, and fluid isotropic phases of hydrated monoacylglycerides monitored by time-resolved X-ray diffraction. Biochemistry. 1987 Oct 6;26(20):6349–6363. doi: 10.1021/bi00394a008. [DOI] [PubMed] [Google Scholar]
- DITTMER J. C., LESTER R. L. A SIMPLE, SPECIFIC SPRAY FOR THE DETECTION OF PHOSPHOLIPIDS ON THIN-LAYER CHROMATOGRAMS. J Lipid Res. 1964 Jan;5:126–127. [PubMed] [Google Scholar]
- Gruner S. M., Tate M. W., Kirk G. L., So P. T., Turner D. C., Keane D. T., Tilcock C. P., Cullis P. R. X-ray diffraction study of the polymorphic behavior of N-methylated dioleoylphosphatidylethanolamine. Biochemistry. 1988 Apr 19;27(8):2853–2866. doi: 10.1021/bi00408a029. [DOI] [PubMed] [Google Scholar]
- Gulik A., Luzzati V., De Rosa M., Gambacorta A. Structure and polymorphism of bipolar isopranyl ether lipids from archaebacteria. J Mol Biol. 1985 Mar 5;182(1):131–149. doi: 10.1016/0022-2836(85)90032-4. [DOI] [PubMed] [Google Scholar]
- Lutton E. S. Phase behavior of aqueous systems of monoglycerides. J Am Oil Chem Soc. 1965 Dec;42(12):1068–1070. doi: 10.1007/BF02636909. [DOI] [PubMed] [Google Scholar]
- Mariani P., Luzzati V., Delacroix H. Cubic phases of lipid-containing systems. Structure analysis and biological implications. J Mol Biol. 1988 Nov 5;204(1):165–189. doi: 10.1016/0022-2836(88)90607-9. [DOI] [PubMed] [Google Scholar]
- Seddon J. M. Structure of the inverted hexagonal (HII) phase, and non-lamellar phase transitions of lipids. Biochim Biophys Acta. 1990 Feb 28;1031(1):1–69. doi: 10.1016/0304-4157(90)90002-t. [DOI] [PubMed] [Google Scholar]
- Shyamsunder E., Gruner S. M., Tate M. W., Turner D. C., So P. T., Tilcock C. P. Observation of inverted cubic phase in hydrated dioleoylphosphatidylethanolamine membranes. Biochemistry. 1988 Apr 5;27(7):2332–2336. doi: 10.1021/bi00407a014. [DOI] [PubMed] [Google Scholar]
- Wack DC, Webb WW. Synchrotron x-ray study of the modulated lamellar phase P beta ' in the lecithin-water system. Phys Rev A Gen Phys. 1989 Sep 1;40(5):2712–2730. doi: 10.1103/physreva.40.2712. [DOI] [PubMed] [Google Scholar]