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A function of lung surfactant protein SP-B
M L Longo1, A M Bisagno, J A Zasadzinski
1Department of Chemical and Nuclear Engineering, University of California, Santa Barbara 93106.
Science (New York, N.Y.)
|July 23, 1993
Summary
Lung surfactant protein SP-B1-25 stabilizes fatty acid monolayers, preventing collapse during exhalation. This peptide’s charge interaction is key, suggesting poly-cations could aid respiratory distress syndrome treatments.
Area of Science:
- Biochemistry
- Pulmonary Medicine
- Materials Science
Background:
- Lung surfactant maintains low surface tension at the alveolar interface.
- Surfactant must form stable monolayers that resist collapse during expiration.
Purpose of the Study:
- To investigate the role of the SP-B1-25 peptide in stabilizing lung surfactant components.
- To determine the mechanism by which SP-B1-25 enhances palmitic acid (PA) isotherms.
Main Methods:
- Studied the effect of the positively charged SP-B1-25 peptide on palmitic acid (PA) isotherms.
- Compared the effects of a charged SP-B1-25 peptide with an uncharged mutant.
- Analyzed the interaction between the cationic peptide and anionic lipids.
Main Results:
- SP-B1-25 significantly increased the collapse pressure of PA to nearly 70 mN/m.
- This stabilization prevented the "squeeze-out" of fatty acids from dipalmitoylphosphatidylcholine monolayers.
- An uncharged SP-B1-25 mutant showed minimal effect, indicating charge-dependent stabilization.
Conclusions:
- The positive charge of SP-B1-25 is crucial for stabilizing PA, likely through specific charge interactions with lipids.
- The stabilization mechanism is similar to that of poly-cations.
- Simple poly-cations may serve as effective components in artificial surfactants for treating respiratory distress syndrome.