title: Surfactant protein A (SP-A) forms a novel supraquaternary structure in the form of fibers.
abstract: We have found by transmission electron microscopy that bovine surfactant protein A (SP-A) formed extended fibers in the presence of calcium. On phosphatidylcholine or especially dipalmitoylphosphatidylcholine monolayers, SP-A at roughly 0.005 mg/ml formed large numbers of fibers and elaborate fibrous networks. This observation suggested that the weak protein:protein interactions amongst free SP-As could be stabilized by phospholipids. In the presence of glycolipid GM1-ganglioside, SP-A's globular headgroup regions appeared enlarged and only small non-fibrous clusters were observed.
authors.affiliation: Department of Molecular Biology and Genetics, The University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Palaniyar
authors.forename: R A
authors.initials: RA
authors.lastname: Ridsdale
authors.forename: F
authors.initials: F
authors.lastname: Possmayer
authors.forename: G
authors.initials: G
authors.lastname: Harauz
mesh_terms: D000818:Animals; D002417:Cattle; D005677:G(M1) Ganglioside / Q000378:metabolism; D008854:Microscopy, Electron; D011485:Protein Binding; D011487:Protein Conformation; D011510:Proteolipids / Q000737:chemistry* / Q000378:metabolism; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000737:chemistry* / Q000378:metabolism
chemical_list: D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D005677:G(M1) Ganglioside