Evidence for the Formation of Symmetric and Asymmetric DLPC-DAPC Lipid Bilayer Domains

• Main Authors: Markus Ritter, Sabine Schmidt, Martin Jakab, Markus Paulmichl, Robert Henderson
• Format: Article
• Language: English
• Published: Cell Physiol Biochem Press GmbH & Co KG 2013-07-01
• Series: Cellular Physiology and Biochemistry
• Subjects: DLPC; DAPC; Lipid bilayer; Lipid domain; Lipid raft; Atomic force microscopy
• Online Access: http://www.karger.com/Article/FullText/350122

Background/Aims: We investigated if mixtures of the phosphatidylcholine (PC) lipids 1,2-dilauroyl-sn-glycero-3-phosphocholine (C12:0 PC; DLPC) and 1,2-diarachidoyl-sn-glycero-3-phosphocholine (C20:0 PC; DAPC), which differ by eight methylene groups in acyl chain length, lead to the spontaneous formation of distinct lipid rafts and asymmetric bilayers. Methods: The experiments were performed using Atomic Force Microscopy (AFM). Results: We show that DLPC and DAPC mixed at a molar ratio of 1:1 lead to the formation of single, double and triple bilayers with peaks at 6.14 ± 0.11, 13.27 ± 0.17 and 20.54 ± 0.46 nm, respectively (n=750). Within these formations discrete height steps of 0.92 nm can be resolved (n=422). Conclusion: The most frequently observed height steps value of 0.92 nm matches best with the calculated mean lipid hydrophobic thickness difference for asymmetric C12:0 PC and C20:0 PC lipid bilayers of 0.88 nm. This indicates the ability of DLPC and DAPC to form asymmetric lipid bilayers.