title: Evidence for the formation of symmetric and asymmetric DLPC-DAPC lipid bilayer domains.
abstract: OBJECTIVE
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Institute of Physiology and Pathophysiology, Paracelsus Medical University Salzburg, Salzburg, Austria. markus.ritter@pmu.ac.at
authors.forename: Markus
authors.initials: M
authors.lastname: Ritter
authors.forename: Sabine
authors.initials: S
authors.lastname: Schmidt
authors.forename: Martin
authors.initials: M
authors.lastname: Jakab
authors.forename: Markus
authors.initials: M
authors.lastname: Paulmichl
authors.forename: Robert
authors.initials: R
authors.lastname: Henderson
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D010713:Phosphatidylcholines / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D010713:Phosphatidylcholines; C044819:1,2-diarachidonoyl-glycero-3-phosphocholine; C015153:1,2-dilauroylphosphatidylcholine