Effects of gramicidin-A on the adsorption of phospholipids to the air-water interface

Samares C. Biswas, Shankar B. Rananavare, Stephen (Steve) Hall

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Prior studies suggest that the hydrophobic surfactant proteins, SP-B and SP-C, promote adsorption of the lipids in pulmonary surfactant to an air-water interface by stabilizing a negatively curved rate-limiting structure that is intermediate between bilayer vesicles and the surface film. This model predicts that other peptides capable of stabilizing negative curvature should also promote lipid adsorption. Previous reports have shown that under appropriate conditions, gramicidin-A (GrA) induces dioleoyl phosphatidylcholine (DOPC), but not dimyristoyl phosphatidylcholine (DMPC), to form the negatively curved hexagonal-II (HII) phase. The studies reported here determined if GrA would produce the same effects on adsorption of DMPC and DOPC that the hydrophobic surfactant proteins have on the surfactant lipids. Small angle X-ray scattering and 31P-nuclear magnetic resonance confirmed that at the particular conditions used to study adsorption, GrA induced DOPC to form the HII phase, but DMPC remained lamellar. Measurements of surface tension showed that GrA in vesicles produced a general increase in the rate of adsorption for both phospholipids. When restricted to the interface, however, in preexisting films, GrA with DOPC, but not with DMPC, replicated the ability of the surfactant proteins to promote adsorption of vesicles containing only the lipids. The correlation between the structural and functional effects of GrA with the two phospholipids, and the similar effects on adsorption of GrA with DOPC and the hydrophobic surfactant proteins with the surfactant lipids fit with the model in which SP-B and SP-C facilitate adsorption by stabilizing a rate-limiting intermediate with negative curvature.

Original languageEnglish (US)
Pages (from-to)41-49
Number of pages9
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1717
Issue number1
DOIs
StatePublished - Nov 10 2005

Fingerprint

Gramicidin
Adsorption
Phospholipids
Air
Surface-Active Agents
Water
Phosphatidylcholines
Lipids
Pulmonary Surfactant-Associated Protein B
Pulmonary Surfactants
Proteins
Surface Tension
X ray scattering
Surface tension
Magnetic Resonance Spectroscopy
Nuclear magnetic resonance
X-Rays
1,2-oleoylphosphatidylcholine
Peptides

Keywords

  • P nuclear magnetic resonance
  • Gramicidin
  • Hydrophobic surfactant protein
  • Lipid polymorphism
  • Pulmonary surfactant
  • Small angle x-ray scattering

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Biophysics

Cite this

Effects of gramicidin-A on the adsorption of phospholipids to the air-water interface. / Biswas, Samares C.; Rananavare, Shankar B.; Hall, Stephen (Steve).

In: Biochimica et Biophysica Acta - Biomembranes, Vol. 1717, No. 1, 10.11.2005, p. 41-49.

Research output: Contribution to journalArticle

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