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 language | English (US) |
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Pages (from-to) | 3977-3986 |
Number of pages | 10 |
Journal | Biophysical Journal |
Volume | 96 |
Issue number | 10 |
DOIs | |
State | Published - 2009 |
Funding
This work is supported by the National Science Foundation under grant Nos. DMR 0803956 (to M.S.), EE-0503943 (to I.S.), and CBET-0828046 (to I.S.), and the National Institutes of Health grant No. NIH CA112427 (to I.S.).
ASJC Scopus subject areas
- Biophysics