Stability and liquid-liquid phase separation in mixed saturated lipid bilayers

Gabriel S. Longo, M. Schick, I. Szleifer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The phase stability of a fluid lipid bilayer composed of a mixture of DC18PC, (DSPC), and a shorter DCns PC, with ns from 8 to 17, has been studied using a self-consistent field theory that explicitly includes molecular details and configurational properties of the lipid molecules. Phase separation between two liquid phases was found when there was a sufficient mismatch between the hydrophobic thicknesses of the two bilayers composed entirely of one component or the other. This occurs when ns ≤ 12 and there is a sufficient concentration of the shorter lipid. The mixture separates into a thin bilayer depleted of DSPC and a thick bilayer enriched in DSPC. Even when there is no phase separation, as in the cases when there is either insufficient concentration of a sufficiently short lipid or any concentration of a lipid with ns > 12, we observe that the effect of the shorter lipid is to increase the susceptibility of the system to fluctuations in the concentration. This is of interest, given that a common motif for the anchoring of proteins to the plasma membrane is via a myristoyl chain, that is, one with 14 carbons.

Original languageEnglish (US)
Pages (from-to)3977-3986
Number of pages10
JournalBiophysical Journal
Volume96
Issue number10
DOIs
StatePublished - 2009

ASJC Scopus subject areas

  • Biophysics

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