Detection of phase separation in fluid phosphatidylserine/phosphatidylcholine mixtures

A. K. Hinderliter, J. Huang, G. W. Feigenson

Research output: Contribution to journalArticlepeer-review

56 Scopus citations

Abstract

The nonideal mixing of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine, (16:0, 18:1)PS, and 1,2-didodecenoyl-sn-glycero-3-phosphocholine, (12:1, 12:1)PC, in fluid lamellar model membranes was studied by measuring binding of aqueous Ca2+ ions and by x-ray diffraction. A region of two-phase coexistence was found by invariance of the aqueous concentration and by the appearance of two sets of lamellar spacings. The phases were identified as fluid from the diffuse x-ray diffraction in the wide-angle region. The width of the two-phase coexistence region was greater at higher ionic strength. In 800 mM KCl, the phase boundaries were at PS mole fraction 0.5 and 0.8. In 100 mM KCl, the phase boundaries were at PS mole fraction 0.52 and 0.62. Monte Carlo simulations of the lateral distributions of these PS/PC mixtures show pronounced clustering of the lipids.

Original languageEnglish
Pages (from-to)1906-1911
Number of pages6
JournalBiophysical Journal
Volume67
Issue number5
DOIs
StatePublished - 1994

Fingerprint Dive into the research topics of 'Detection of phase separation in fluid phosphatidylserine/phosphatidylcholine mixtures'. Together they form a unique fingerprint.

Cite this