Phys Rev E Stat Nonlin Soft Matter Phys
Raman Research Institute, Bangalore 560 080, India.
Published: September 2003
We present electron density maps (EDMs) of the ripple phase formed by phosphorylcholine lipids such as dimyristoyl phosphatidylcholine (DMPC), palmitoyl-oleoyl phosphatidylcholine (POPC), dihexadecyl phosphatidylcholine, and dilauroyl phosphatidylcholine (DLPC). With the exception of DLPC, the rippled bilayers have a sawtooth shape in all the systems, with one arm being almost twice as long as the other. For DMPC and POPC bilayers, EDMs have been obtained at different temperatures at a fixed relative humidity, and the overall shape of the ripples and the ratio of the lengths of the two arms are found to be insensitive to temperature. EDMs of all the systems with saturated hydrocarbon chains suggest the existence of a mean chain tilt along the ripple wave vector. In the literature it is generally assumed that the asymmetry of the rippled bilayers (absence of a mirror plane normal to the ripple wave vector) arises from a sawtoothlike height profile. However, in the case of DLPC, the height profile is found to be almost symmetric and the asymmetry results mainly from different bilayer thicknesses in the two arms of the ripple. We also present EDMs of the metastable ripple phase of dipalmitoyl phosphatidylcholine, formed on cooling from the L(alpha) phase.
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http://dx.doi.org/10.1103/PhysRevE.68.031710 | DOI Listing |
Nature
January 2025
Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
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Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland.
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Power Electronics Research Laboratory (PERL), Faculty of Electrical Engineering, Sahand University of Technology, Tabriz, Iran.
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ENET Centre, VSB-Technical University of Ostrava, Ostrava, 708 00, Czech Republic.
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Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria.
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