Role of head group structure in the phase behavior of amino phospholipids. 2. Lamellar and nonlamellar phases of unsaturated phosphatidylethanolamine analogues.

摘要: Three types of analogues unsaturated phosphatidylethanolamines (PE) have been prepared: phosphatidyl-omega-amino-1-alkanols, N-alkyl-PE's, and C2-alkyl-PE's, with alkyl substitution carbon-2 the ethanolamine head group. The physical properties dioleoyl, dielaidoyl, 1-palmitoyl-2-oleoyl phospholipids these groups examined by calorimetry, 31P NMR, freeze-fracture electron microscopy, X-ray diffraction. N-Alkylation PE, or moiety 3-amino-1-propanol 4-amino-1-butanol, decreases transition temperature hydrated gel phase (Tc) considerably increases lamellar to hexagonal II (TH). pattern effects for various PE suggests that group size hydrophobicity as well hydrogen bonding are important determinants behavior lipids. C2-Alkylated exhibit several rather surprising properties, notably ready formation a quasi-crystalline "high-melting" solid even di-cis-unsaturated species substantially lower TH values than observed parent species. compounds "hydration forces" can be more considerations lipid "dynamic shape" in predicting relative stabilities vs. nonlamellar phases at least some zwitterionic phospholipids.