Document Detail

Solubility of hydrophobic surfactant proteins in organic solvent/water mixtures. Structural studies on SP-B and SP-C in aqueous organic solvents and lipids.
MedLine Citation:
PMID:  8323965     Owner:  NLM     Status:  MEDLINE    
The solubility of hydrophobic pulmonary surfactant proteins in different organic solvents and organic solvent/water combinations has been analyzed. Three organic solvents have been selected: methanol (MetOH), acetonitrile (ACN) and trifluoroethanol (TFE). Porcine SP-B showed very similar calculated secondary structure when dissolved in methanol, 60% ACN or 70% TFE and reconstituted in lysophosphatidylcholine (LPC) micelles or dipalmitoylphosphatidylcholine (DPPC) vesicles, as deduced from circular dichroism studies. SP-B was calculated to possess around 45% of alpha-helix in all these systems. The fluorescence emission spectrum of SP-B has been also characterized in aqueous solvents and lipids. It always showed a splitting of the tryptophan contribution into two components with different emission maxima. SP-C had a very different structure in 80% ACN or 70% TFE. While alpha-helix was the main secondary structure of SP-C in ACN/water mixtures--around 50%--, it had almost exclusively beta-structure when dissolved in 70% TFE. The CD spectrum of SP-C in TFE showed dependence on the protein concentration, suggesting that protein-protein interactions could be important in this beta-conformation. SP-C reconstituted in LPC micelles or DPPC vesicles had a CD spectrum qualitatively similar to that one in aqueous ACN, with a dominant alpha-helical structure. The alpha-helical content of SP-C in micelles of LPC and vesicles of DPPC, 60 and 70%, respectively, was calculated to be higher than the alpha-helical content of the protein dissolved in any aqueous organic solvent.
J Pérez-Gil; A Cruz; C Casals
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1168     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  1993 Jul 
Date Detail:
Created Date:  1993-08-10     Completed Date:  1993-08-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  261-70     Citation Subset:  IM    
Dept Bioquímica y Biología Molecular I, Fac. Ciencias Químicas, Universidad Complutense de Madrid, Spain.
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MeSH Terms
Amino Acid Sequence
Molecular Sequence Data
Proteolipids / chemistry*,  isolation & purification
Pulmonary Surfactants / chemistry*,  isolation & purification
Reg. No./Substance:
0/Acetonitriles; 0/Micelles; 0/Proteolipids; 0/Pulmonary Surfactants; 0/Solvents; 2644-64-6/1,2-Dipalmitoylphosphatidylcholine; 67-56-1/Methanol; 75-05-8/acetonitrile; 75-89-8/Trifluoroethanol; 7732-18-5/Water

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