STRUCTURE AND FUNCTION OF SURFACTANT PROTEIN D

肺泡被一层薄薄的表面活性物质覆盖。 材料，称为肺表面活性物质。这种材料，它是 正常气体交换所必需的，由磷脂和特定的 蛋白质。最具特性的表面活性蛋白包括SP-A和两个 较小的疏水蛋白，SP-B和SP-C。我们最近提纯了一种 大鼠肺胶原表面活性物质相关糖蛋白。这 被命名为SP-D的蛋白质不同于SP-A和前面描述的蛋白质 胶原蛋白。初步实验表明，SP-D具有 在体外具有碳水化合物结合活性，并具有结构性 SP-D与C型(钙依赖)凝集素的同源性。这是我们的 假设碳水化合物结合活性中介相互作用 SP-D与其他组分的表面活性物质，以及碳水化合物介导的 相互作用有助于该蛋白和肺功能的发挥 活体内的表面活性物质。我们提出了以下具体目标： 1.进一步明确SP-D的结构； 2.鉴定其碳水化合物结合活性； 3.确定表面活性剂中SP-D的配体； 4.探讨SP-D对表面活性物质的可能贡献 活动和新陈代谢。 这些研究应该会为我们提供有关 肺泡巨噬细胞的大分子组成、组织和功能 表面活性物质，以及胶原凝集素的结构和功能。

The alveoli of the lung are covered by a thin layer of surface-active material, referred to as pulmonary surfactant. This material, which is essential for normal gas exchange, consists of phospholipids and specific proteins. The best characterized surfactant proteins include SP-A, and two smaller hydrophobic proteins, SP-B and SP-C. We have recently purified a collagenous surfactant-associated glycoprotein from rat lung. This protein, designated SP-D, is different that SP-A and previously described collagenous proteins. Preliminary experiments indicate that SP-D has carbohydrate-binding activity in vitro, and that there is structural homology of SP-D with the C-type (calcium-dependent) lectins. It is our hypothesis that the carbohydrate-binding activity mediates interactions of SP-D with other components of surfactant, and that carbohydrate-mediated interactions contribute to the function of this protein and pulmonary surfactant in vivo. We propose the following specific aims: 1. To further define the structure of SP-D; 2. To characterize its carbohydrate-binding activity; 3. To identify the ligands for SP-D in surfactant; and 4. To explore the possible contributions of SP-D to surfactant activity and metabolism. These studies should contribute important new information relating to the macromolecular composition, organization, and functions of pulmonary surfactant, and to the structure and function of collagenous lectins.