H. Binder, K. Gawrisch
Nov 13, 2001
Citations
2
Influential Citations
107
Citations
Quality indicators
Journal
Journal of Physical Chemistry B
Abstract
We conducted infrared linear dichroism and X-ray measurements to characterize membranes of sn-1 chain perdeuterated, polyunsaturated 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (18:0−22:6ω3 PC, SDPC-d35) and of monounsaturated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (16:0−18:1 PC, POPC-d31) as a function of hydration and temperature. Our novel approach is to use IR order parameters of C−H and C−D vibrations of both sn-1 and sn-2 chains for a separate estimation of the mean length and effective cross sectional area of the saturated and unsaturated chains in the bilayers. In the gel phase, the thickness of the hydrophobic core of SDPC bilayers exceeded the thickness of POPC bilayers, because the polyunsaturated chains adopted an extended conformation. However, in the fluid phase, the hydrophobic thickness of SDPC membranes, with the longer 18:0 and 22:6 acyl chains, was almost equal to the thickness of the 16:0−18:1 chains in POPC membranes. The isothermal compressibility modulus of th...