PULMONARY SURFACTANT PROTEINS SP-B AND SP-C IN SPREAD MONOLAYERS AT THE AIR-WATER-INTERFACE .1. MONOLAYERS OF PULMONARY SURFACTANT PROTEIN SP-B AND PHOSPHOLIPIDS

被引:96
|
作者
TANEVA, S
KEOUGH, KMW
机构
[1] MEM UNIV NEWFOUNDLAND,DEPT BIOCHEM,ST JOHNS A1B 3X9,NF,CANADA
[2] MEM UNIV NEWFOUNDLAND,DISCIPLINE PEDIAT,ST JOHNS A1B 3X9,NF,CANADA
基金
英国医学研究理事会;
关键词
D O I
10.1016/S0006-3495(94)80895-1
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
The effects of pulmonary surfactant protein SP-B on the properties of monolayers of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG), and a mixture of DPPC:DPPG (7:3, mol:mol) were studied using spread films at the air-water interface. The addition of SP-B to the phospholipid monolayers gave positive deviations from additivity of the mean areas in the films. At low protein concentrations (less than 45% amino acid residues which corresponds to 0.5 mol% or 10 weight% SP-B) monolayers of SP-B/DPPC, SP-B/DPPG and SP-B/(DPPC:DPPG) collapsed at surface pressures of about 70 mN.m(-1), comparable to those of the lipids alone. At higher concentrations of SP-B in the protein-lipid monolayers, kink points appeared in the isotherms at about 40-45 mN.m(-1), implying possible exclusion of material from the films, hence, changes in the original monolayer compositions. Calculated analyses of the monolayer compositions as a function of surface pressure indicated that nearly pure SP-B, associated with small amounts of phospholipid (2-3 lipid molecules per SP-B dimer), was lost from SP-B/DPPC, SP-B/DPPG, and SP-B/(DPPC:DPPG) films at surface pressures higher than 40-45 mN.m(-1). The results are consistent with a low effectiveness of SP-B in removing saturated phospholipids, DPPC or DPPG, from the spread SP-B/phospholipid films.
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页码:1137 / 1148
页数:12
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