Time-resolved simultaneous small- and wide-angle x-ray diffraction on dipalmitoylphosphatidylcholine by laser temperature-jump
The kinetics of the structural phase transitions of dipalmitoylphosphatidylcholine (DPPC) in excess water have been investigated by simultaneous small- and wide-angle detection in millisecond time-resolved synchrotron x-ray diffraction. The transition from the rippled to liquidcrystalline phase (P′β(mst) - L a ) has been induced by an approx. 5°C temperature-jump within 2 ms using an erbium glass laser. The structural parameters, i.e., the long-range order of the bilayer stacking and the short-range order of the lateral lipid packing have been detected with 5 ms time-resolution. The experiments show that the intensities of both the small- and the wide-range reflections indicative of the P′β(mst)-structure decay in parallel and on the same time-scale as the first- and second- order reflections of the lamellar lattice of the L a -phase grow in intensity. For the ppretransition, we have made the important observation that the rearrangement of the hydrocarbon chains is slower than the initial changes in the long-range lamellar lattice.
Key wordsSmall- and wide-angle x-ray diffraction synchrotron radiation IR-laser T-jump phospholipids phase transitions
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- 3.Cevc G, Marsh D (1987) Phospholipid Bilayers, Physical Principles and Models Wiley, New YorkGoogle Scholar
- 4.Cevc G (1991) Chem Phys Lipids, Special Issue on Phospholipid Phase Transitions (Kinnunen P, Laggner P eds) 57:293–307Google Scholar
- 9.Katsaras J, Yang DSC, Epand R (1992) Biophys J 63:1170–1175Google Scholar
- 11.Laggner P (1986) New Methods in Absorption, Scattering and Diffraction for Applications in Structural Biology (Chance B, Bartunik HD eds) Academic Press London pp 171–182Google Scholar
- 13.Laggner P, Kriechbaum M (1991) Chem Phys Lipids, Special Issue on Phospholipid Phase Transitions (Kinnumen P, Laggner P eds) 57:121–145Google Scholar
- 15.Laggner P, Kriechbaum M, Hermetter A, Paltauf F, Hendrix J, Rapp G (1989) Progr Colloid Polym Sci 79:33–37Google Scholar
- 20.Small DM (1986) Handbook of Lipid Research, Vol IV: The Physical Chemistry of Lipids, from Alkanes to Phospholipids, Plenum Press, New YorkGoogle Scholar
- 22.Tenchov BG, Yao H, Hatta I (1989) Biophys J 56:757Google Scholar
- 23.Tenchov BG (1991) Chem Phys Lipids, Special Issue on Phospholipid Phase Transitions (Kinnunen P, Laggner P eds) 57:165–177Google Scholar
- 24.Yao H, Matuoka S, Tenchov BG, Hatta I (1991) Biophys J 59:252Google Scholar