Modifying dipalmitoylphosphatidylcholine monolayers by n-hexadecanol and dipalmitoylglycerol.
The monolayer structure of pure dipalmitoylphosphatidylcholine (DPPC) and equimolar mixtures of DPPC/n-hexadecanol (C(16)OH) and DPPC/dipalmitoylglycerol (DPG) are studied by the film balance technique and grazing incidence X-ray diffraction measurements. At 20 degrees C, the binary systems exhibit complete miscibility. In contrast to pure DPPC monolayers, a condensing effect is observed in the presence of both non-phospholipid additives; but the phase transition behavior differs. The tilt angle of the hydrocarbon chains in the DPPC/C(16)OH mixture is significantly smaller than in pure DPPC monolayers. The tilt of the chains is even further reduced in the mixed monolayer of DPPC/DPG. A comparison of the three systems reveals distinct structural features such as phase state, chain tilt, and molecular area over a wide range of surface pressures. Therefore, these monolayers provide a highly suitable model to investigate the influence of structural parameters on biological processes occurring at the membrane surface, e.g. enzymatic reactions and adsorption events.
Wagner
Kerstin
K
Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany. wagner@mpikg.mpg.de
Brezesinski
Gerald
G
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D004075:Diglycerides / Q000737:chemistry*; D005233:Fatty Alcohols / Q000737:chemistry*; D008567:Membranes, Artificial; D008968:Molecular Conformation; D013500:Surface Tension; D014961:X-Ray Diffraction
D004075:Diglycerides; D005233:Fatty Alcohols; D008567:Membranes, Artificial; D015060:1,2-Dipalmitoylphosphatidylcholine; C005071:dipalmitin; C005031:cetyl alcohol