Hydration of DMPC and DPPC at 4°C produces a novel subgel phase with convex–concave bilayer curvatures

Kinetics for the subgel phase formation in DPPC/DOPC mixed bilayers

“…This phenomenon is hardly explained in a simple way considering that DOPC molecules are likely to sterically disturb the ordered lipid packing. One of the possibilities is that the bending elastic energy of the bilayer is reduced more prominently in the SGI phase than in the Lˇ phase by intercalation of flexible fluid domains between highly ordered domains; the convex-concave surface, which the subgel phase is imposed to have due to compensation between the flatness of the surface and the formation of a closed vesicle (Meyer et al, 1998(Meyer et al, , 2000, can be smoothed out if DOPC-rich fluid domains surround the rigid domains in the subgel phase. Further study is needed to clarify the detailed energetics of the phase behavior in the DPPC/DOPC binary system.…”

“…The metastable SGII phase formation involves ordering in lipid hydrocarbon chains (Tenchov et al, 2001) and the subgel phase formation involves a series of structural changes such as reduction of the number of interbilayer water molecules per lipid from 19 in the Lˇ phase to 11 in the subgel phase and two-dimensional crystallization in a single bilayer (Ruocco and Shipley, 1982;McIntosh and Simon, 1993;Nagle et al, 1998). Since the two-dimensional crystallization results in flattening of the bilayer membrane, the bilayer vesicle has a crinkled surface so as to keep the closed vesicular morphology (Singer and Finegold, 1985;Meyer et al, 1998Meyer et al, , 2000.…”

Hybrid QM/MM simulation of the hydration phenomena of dipalmitoylphosphatidylcholine headgroup

“…Some properties of biological membranes can be directly attributed to the characteristics of single phospholipid molecules. Due to their important role, phospholipids are the subject of numerous experimental and computational studies in recent decades [2][3][4][5][6][7][8].…”

Novel Lipid Nanotubes in Dispersions of DMPC

“…[6] Recently, some solitary conical tubelike extensions with screwlike rimsreminiscent of the present nanotubes-were noticed in bulk DMPC preparations which had been hydrated below T m and which exhibited mainly convex±concave bilayer deformations. [7] Here, we found for the first time large quantities of long unilamellar, helically rippled tubular vesicles, when DMPC dispersions were prepared by high pressure homogenization and stored at 13 8C. Due to their unique structure these lipid nanotubes are clearly distinct from any other tubular morphology in the literature, and a mechanism of formation has been proposed for this novel species.…”