LIPID AND PROTEIN EFFECTS ON MONOLAYER STABILITY

出生时肺表面活性物质缺乏，通常是由于早产，是 对新生儿呼吸窘迫综合征(NRDS)负责。 肺表面活性物质失活，可能是由于与血液的相互作用 血清或蛋白质，可能参与成人的发育 呼吸窘迫综合征(ARDS)。身体和/或身体上的变化 肺表面活性物质的化学性质经常伴随着吸烟和 其他疾病。这些疾病的严重发病率和死亡率 肺表面活性物质在正常和病变肺中的作用是必要的 明白了。 我们将检验三个一般假设：(1)特定的相互作用 在SP-B和肺表面活性物质常见的脂肪酸之间导致更多 稳定的抗坍塌单层。然而，目前还不清楚是否 这种蛋白质的存在是为了将脂肪酸保留在单层或副层中 反过来说。不饱和之间不存在类似的相互作用 磷脂酰甘油和SP-B，表明PG被“挤出” 在压缩方面。(2)这些特定的蛋白质-脂肪酸相互作用可以是 在溶液中由简单的聚合物离子模拟，或由 与其他带电蛋白质的特定相互作用，如纤维蛋白原或 白蛋白，或可能导致的脂类，如溶血磷脂酰胆碱 由疾病引起的肺环境变化；以及(3)详细的 在分子水平上的结构-功能关系 天然肺表面活性物质的成分是开始合理的 设计了一种纯合成的肺表面活性物质来解决这些假设， 我们将(1)测定天然肺表面活性物质的相行为和 它的部件使用朗缪尔海槽。特别是，我们将尝试 了解肺表面活性物质特异性蛋白与肺表面活性物质的相互作用 导致崩解压力增加和降低的表面活性脂类 张力；(2)构造能够可视化的布鲁斯特角显微镜 气-水界面和单分子膜上的单层坍塌 转移到固体物质；(3)完成显影的一种极化 用荧光显微镜(PFM)观察单层膜中的相分离 对荧光标记的SP-B蛋白和多肽进行定位；(4)检测 坍塌的单分子膜通过电子和电子转移到固体衬底上 原子力显微镜。单层工作将使用模型进行扩展 可通过分子拆分分析的崩塌系统 支撑单分子膜的原子力显微镜；(5)将我们的实验工作与 模型脂和模型脂之间作用力和相互作用的理论模型 分子水平上的脂蛋白单层。这个分子水平 了解这一点对于设计取代SP-B的新多肽至关重要， 它是目前成本最高、也是潜在危险最大的 替代肺表面活性物质。

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.