- Simon, S.A. and McIntosh, T.J. and Magid, A.D. and Needham, D., Modulation of the interbilayer hydration pressure by the addition of dipoles at the hydrocarbon/water interface,
Biophys. J. (USA), vol. 61 no. 3
pp. 786 - 99 .
(last updated on 2007/04/06)
The effects of the cholesterol analog 5α-cholestan-3β-ol-6-one (6-ketocholestanol) on bilayer structure, bilayer cohesive properties, and interbilayer repulsive pressures have been studied by a combination of X-ray diffraction, pipette aspiration, and dipole potential experiments. It is found that 6-ketocholestanol, which has a similar structure to cholesterol except with a keto moiety at the 6 position of the B ring, has quite different effects than cholesterol on bilayer organization and cohesive properties. Unlike cholesterol, 6-ketocholestanol does not appreciably modify the thickness of liquid-crystalline egg phosphatidylcholine (EPC) bilayers, and causes a much smaller increase in bilayer compressibility modulus than does cholesterol. These data imply that 6-ketocholestanol has both its hydroxyl and keto moieties situated near the water-hydrocarbon interface, thus making its orientation in the bilayer different from cholesterol's
bioelectric potentials;biomechanics;lipid bilayers;molecular biophysics;X-ray diffraction examination of molecular structure;