Order-disorder conformational transitions of the hydrocarbon chains of lipids

The structural diversity of DNA–neutral phospholipids–divalent metal cations aggregates: a small-angle synchrotron X-ray diffraction study

“…The fully hydrated DPPC forms a lamellar phase in the temperature range 20- phase of nonoriented bilayers with lipid acyl chains tilted with respect to bilayer normal (Ranck et al, 1974). At higher temperatures (t ≈ 39 o C) we observe a change in the shape of the peak: it becomes symmetric (Fig.…”

“…1, 39 o C). The symmetric shape of the peak in the WAX region is characteristic of the organization of the acyl chains perpendicular to the surface of the bilayer (gel L β or P β phase) (Ranck et al, 1974). Above 45 o C, the WAX region of the diffractograms shows a wide diffuse scattering typical of liquid-like acyl chains of DPPC molecules ( Fig.…”

The structure of a lipid–water lamellar phase containing two types of lipid monolayers. An X-ray and neutron scattering study

“…More recently, we reinvestigated the structure of this 293 ~/1 273 253 uL~). phase using more sophisticated procedures for determining the signs of the reflections (Ranck et al, 1974); we ended up with two classes of solutions, which appeared as equally satisfactory. The two structures are represented in Fig.…”

“…The proportion of the chains in each of the two conformations and their distribution vary with the nature of the lipid, temperature and water content. Some of the phases involved in the transition are lamellar, others display a twodimensional lattice and contain lipid lamellae distorted by wave-like ripples (Ranck et al, 1974).…”

“…We are concerned here with one phase observed in mitochondrial lipids, which we named L^~ (GulikKrzywicki, Rivas & Luzzati, 1967;Ranck et al, 1974). This phase is observed in a narrow concentration range and at low temperature (see Fig.…”