PMID: 9548588Apr 21, 1998Paper

Interaction of pulmonary surfactant protein A with dipalmitoylphosphatidylcholine and cholesterol at the air/water interface.

Journal of Lipid Research
S H Yu, F Possmayer

Abstract

Interaction of pulmonary surfactant protein A (SP-A) with pure and binary mixed dipalmitoylphosphatidylcholine (DPPC) and cholesterol (3.5 wt%) at the air/saline, 1.5 mM CaCl2 interface was investigated using a rhomboid surface balance at 37 degrees C. Surface tension-area isotherms were measured to access the surface active properties of the monolayers. The organization of DPPC and cholesterol in DPPC and DPPC/cholesterol mixed monolayers with or without SP-A at equilibrium surface tension (approximately 23 mN/N) was revealed by autoradiographs of Langmuir-Blodgett (L-B) films deposited from [14C]DPPC or [14C]cholesterol-labeled monolayers. The results showed that SP-A can interact with the polar head groups of DPPC monolayers and aggregate DPPC molecules. SP-A decreased the surface area reduction required for DPPC monolayers to achieve near zero surface tension from 30 to 25% of the area at equilibrium. SP-A also reduced the collapse surface tension of pure cholesterol from 27 to 23 mN/m. DPPC and cholesterol formed homogeneous mixed monolayers when both were dissolved in the spreading solvent prior to spreading, while separate cholesterol-rich domains appeared when DPPC and cholesterol were spread successively. Cholesterol r...Continue Reading

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.