Sialic acid of lung surfactant apoprotein, SP 28-36, is not required for the Ca2+-mediated interactions between surfactant lipids and SP 28-36.
We examined whether removal of sialic acid from the lung surfactant apoprotein (SP 28-36) affected certain properties of reassembled surfactant lipid-SP 28-36 complexes. SP 28-36 was treated with neuraminidase and then added to liposomes made from extracted surfactant lipids. We found that in the presence of Ca2+ the asialoprotein was as effective as the native SP 28-36 in binding to surfactant lipids, causing aggregation and promoting rapid surface film formation.
D001059:Apoproteins / Q000378:metabolism*; D001665:Binding Sites; D002118:Calcium / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D050356:Lipid Metabolism; D008081:Liposomes / Q000378:metabolism; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase; D011485:Protein Binding; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism*
D001059:Apoproteins; D008081:Liposomes; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D012794:Sialic Acids; C046616:pulmonary surfactant apoprotein; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid; D002118:Calcium