LIPID AND PROTEIN EFFECTS ON MONOLAYER STABILITY

出生时缺乏表面活性剂，通常是由于早产， 新生儿呼吸窘迫综合征（NRDS）的病因。 肺表面活性物质失活，可能是由于与血液相互作用 血清或蛋白质，可能参与成人的发育 呼吸窘迫综合征（ARDS）。物理和/或 肺表面活性物质的化学性质通常伴随着吸烟的损害， 其它疾病这些疾病的严重发病率和死亡率 必须考虑表面活性剂在正常和患病肺中的作用， 明白 我们将研究三个一般假设：（1）特定的相互作用 SP-B和肺表面活性剂常见的脂肪酸之间的相互作用导致 稳定的单分子层，抗塌陷。然而，目前尚不清楚是否 存在蛋白质以将脂肪酸保留在单层中，或反之亦然。 亦然不饱和脂肪酸之间不存在类似的相互作用。 磷脂酰甘油和SP-B，这表明PG是“挤出” 在压缩。(2)这些特定的蛋白质-脂肪酸相互作用可以是 被溶液中的简单聚合物gegenions模仿或被 与其他带电蛋白质如纤维蛋白原或 白蛋白，或脂质，如溶血磷脂酰胆碱， 从疾病引起的肺环境的变化;和（3）详细的 分子水平上的结构-功能关系 天然肺表面活性剂的成分是必要的，开始合理的 设计纯合成的肺表面活性剂来解决这些假设， 我们将（1）确定天然肺表面活性剂的相行为， 它的组成部分使用朗缪尔槽。特别是，我们将尝试 为了了解肺表面活性物质特异性蛋白与 表面活性剂脂质，其导致增强的坍塌压力和降低的 张力;（2）构建能够可视化的布鲁斯特角显微镜 在空气-水界面和单分子层上的单分子层坍塌 转移到固体物质;（3）完成偏振的显影 荧光显微镜（PFM），用于观察单层中的相分离 并定位荧光标记的SP-B蛋白和肽;（4）检测 坍塌的单层转移到固体基板与电子和 原子力显微镜单层工作将使用一个模型进行扩展 该系统的崩溃是服从分子分辨率分析，通过 支撑单分子膜的AFM;（5）将我们的实验工作与 力和模型脂质之间的相互作用的理论模型， 在分子水平上的脂质-蛋白质单层。这种分子水平 理解对于设计新的肽来取代SP-B是必不可少的， 这是目前最昂贵和潜在危险的组成部分， 替代肺表面活性剂。

A deficiency of surfactant at birth, often due to premature delivery, is responsible for neonatal respiratory distress syndrome (NRDS). Inactivation of lung surfactant, perhaps due to interactions with blood serum or proteins, is likely involved in the development of adult respiratory distress syndrome (ARDS). Alterations in the physical and/or chemical nature of lung surfactant often accompany damage from smoking and other diseases. The serious morbidity and mortality of these diseases necessitates that the role of surfactant in normal and diseased lungs be understood. We will examine three general hypotheses: (1) Specific interactions between SP-B and fatty acids common to lung surfactants result in more stable monolayers resistant to collapse. However, it is unclear whether the protein is present to retain the fatty acid in the monolayer, or vice versa. Similar interactions do not exist between unsaturated phosphatidylglycerols and SP-B, suggesting that the PG is "squeezed-out" on compression. (2) These specific protein-fatty acid interactions can be mimicked by simple polymer gegenions in solution or compromised by specific interactions with other charged proteins such as fibrinogen or albumin, or by lipids such as lysophosphatidylcholine which may result from disease-induced changes in the lung environment; and (3) A detailed structure-function relationship at the molecular level between the components of natural lung surfactants is necessary to begin a rational design of a purely synthetic lung surfactant to address these hypotheses, we will (1) determine the phase behavior of natural lung surfactant and its components using the Langmuir trough. In particular, we will attempt to understand the interactions of lung surfactant specific proteins with surfactant lipids that lead to enhanced collapse pressures and lower tensions; (2) construct a Brewster Angle Microscope capable of visualizing monolayer collapse at the air-water interface and on monolayers transferred to solid substances; (3) finish development of a polarized fluorescence microscope (PFM) to visualize phase separation in monolayers and localize fluorescent labelled SP-B proteins and peptides; (4) examine collapsed monolayers transferred to solid substrates with electron and atomic force microscopy. The monolayer work will be extended using a model system of collapse that is amenable to molecular resolution analysis via AFM of supported monolayers; (5) correlate our experimental work with theoretical models of the forces and interactions between model lipid and lipid-protein monolayers at the molecular level. This molecular level understanding is essential to designing new peptides to replace SP-B, which is currently the most costly and potentially hazardous component of replacement lung surfactants.