Direct visualization of asymmetric behavior in supported lipid bilayers at the gel-fluid phase transition

Z. Vivian Feng, Tighe A. Spurlin, Andrew A. Gewirth

Research output: Contribution to journalArticlepeer-review

Abstract

We utilize in situ, temperature-dependent atomic force microscopy to examine the gel-fluid phase transition behavior in supported phospholipid bilayers constructed from 1,2-dimyristoyl-sn-glycero-3-phosphocholine, 1,2-dipentadecanoyl-sn-glycero-3-phosphocholine, and 1,2-dipalmitoyl-sn-glycero- 3-phosphocholine. The primary gel-fluid phase transition at Tm occurs through development of anisotropic cracks in the gel phase, which develop into the fluid phase. At ∼5°C above Tm, atomic force microscopy studies reveal the presence of a secondary phase transition in all three bilayers studied. The secondary phase transition occurs as a consequence of decoupling between the two leaflets of the bilayer due to enhanced stabilization of the lower leaflet with either the support or the water entrained between the support and the bilayer. Addition of the transmembrane protein gramicidin A or construction of a highly defected gel phase results in elimination of this decoupling and removal of the secondary phase transition.

Original languageEnglish (US)
Pages (from-to)2154-2164
Number of pages11
JournalBiophysical journal
Volume88
Issue number3
DOIs
StatePublished - Mar 2005

ASJC Scopus subject areas

  • Biophysics

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