Synthesis and characterization of carbohydrate-based phospholipids.
Novel carbohydrate-based phospholipids containing two saturated C(12) (dilauroyl ribo-phosphocholine) (DLRPC), C(14) (dimyristoyl ribo-phosphocholine) (DMRPC), and C(20) (diarachadonyl ribo-phosphocholine) (DARPC) carboxylic acid chains were synthesized. The physical properties of the supramolecular structures formed by these compounds were compared to those formed by their direct glycerol analogues dilauroyl phosphocholine (DLPC), dimyristoyl phosphocholine (DMPC), and diarachadonyl phosphocholine (DAPC). Modulated differential scanning calorimetry (MDSC) and X-ray diffraction data indicated that with chain lengths < or =14 carbons, the carbohydrate backbone increased the thermal stability of the bilayer below the phase-transition temperature (T(m)) as compared to the glycerol-based lipids. With longer chains (C(20)), the bilayer structure was destabilized as compared to glycerol-based lipids. NMR studies of a DMRPC vesicle dispersion reveal split choline headgroup signals and distinct magnetization transfer effects arising from the "inner" and "outer" surfaces of the bilayer vesicle. Modulated differential scanning calorimetry also demonstrated that glycerol- and carbohydrate-based lipids mix, as evidenced by a single intermediate T(m). In addition, carbohydrate-based lipid/cholesterol mixtures exhibited a decrease in enthalpy with an increase in cholesterol concentration. Unlike glycerol phospholipids, carbohydrate lipids were resistant to enzymatic degradation by phospholipase A(2) (PLA(2)).
Hird
Geoffrey S
GS
Department of Chemistry, Paul M. Gross Chemical Laboratory, Duke University, Durham, North Carolina 27708, USA.
McIntosh
Thomas J
TJ
Ribeiro
Anthony A
AA
Grinstaff
Mark W
MW
D002152:Calorimetry, Differential Scanning; D002241:Carbohydrates / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism; D006868:Hydrolysis; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010741:Phospholipases A / Q000737:chemistry / Q000378:metabolism; D010743:Phospholipids / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D013816:Thermodynamics; D014961:X-Ray Diffraction
D002241:Carbohydrates; D008051:Lipid Bilayers; D010743:Phospholipids; D010767:Phosphorylcholine; D002784:Cholesterol; D010741:Phospholipases A