Molecular structures and interactions of pulmonary surfactant components.

摘要: The dominating functional property of pulmonary surfactant is to reduce the surface tension at alveolar air/liquid interface, and thereby prevent lungs from collapsing end expiration. In addition, system exhibits host-defense properties. Insufficient amounts in premature infants causes respiratory distress syndrome, a serious threat which nowadays can be effectively treated by airway instillation preparations. Surfactant mixture many molecular species, mainly phospholipids specific proteins, protein A (SP-A), SP-B, SP-C SP-D. SP-A SP-D are water-soluble belong collectins, family large multimeric proteins structurally exhibit collagenous/lectin hybrid properties functionally Ca2+-dependent carbohydrate binding involved innate host-defence functions. also bind lipids organization phospholipids. SP-B belongs another includes lipid-interacting polypeptides with antibacterial lytic 17.4-kDa homodimer each subunit contains three intrachain disulphides has been proposed contain four amphipathic helices oriented pairwise an antiparallel fashion. SP-A, all have detected gastrointestinal tract. SP-C, contrast, appears unique extreme structural stability exist exclusively lungs. lipopeptide containing covalently linked palmitoyl chains folded into 3.7-nm alpha-helix central 2.3-nm all-aliphatic part, making it perfectly suited interact transmembranous way fluid bilayer composed dipalmitoylglycerophosphocholine, main component surfactant. Homozygous genetic deficiency proSP-B lethal soon after birth associated aberrant processing precursor SP-C. This review focuses on chemical composition, structures interactions surfactant, particular proteins.