title: Lipid polymorphism.
abstract: The phase behavior of phospholipids may be monitored using 31P or 2H NMR techniques, which provide information concerning the motional properties of the lipid ensemble, which may then be correlated with structure. The lamellar/nonlamellar phase preferences of many lipids, either synthetic or naturally derived, may be controlled by factors such as variation in temperature, hydration, or of greater physiological relevance, pH, ionic strength, the presence of divalent cations such as calcium, or the presence of lipid soluble agents as anesthetics and alcohols. The ability of short-chain alcohols to stabilize a bilayer structure for egg PE may be rationalized in terms of the packing of lipids whose dynamic shapes are complementary, as illustrated in Figure 11. On the basis, short-chain alcohols would partition preferentially at the membrane/water interface and would thereby stabilize a lamellar structure. Larger-chain alcohols may partition deeper into the hydrophobic acyl chain region in order to minimize hydrocarbon/water contact and so may perturb the acyl chain packing, increasing the effective swept volume of the chains and so promoting hexagonal HII phase formation.
mesh_terms: D000779:Anesthetics, Local; D000431:Ethanol; D005614:Freeze Fracturing; D008055:Lipids; D008081:Liposomes; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008854:Microscopy, Electron; D008968:Molecular Conformation; D010743:Phospholipids; D013329:Structure-Activity Relationship
chemical_list: D000779:Anesthetics, Local; D008055:Lipids; D008081:Liposomes; D008823:Micelles; D010743:Phospholipids; D000431:Ethanol