Surfactant Protein A (SP-A) Forms a Novel Supraquaternary Structure in the Form of Fibers

摘要: 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 large numbers and elaborate fibrous networks. This observation suggested weak protein:protein interactions amongst free SP-As could be stabilized phospholipids. In glycolipid GM1-ganglioside, SP-A's globular headgroup regions appeared enlarged only small non-fibrous clusters were observed.