SPECTROSCOPY OF BIOMEMBRANE MONOLAYERS

本提案中所述研究的总体长期目标是 使用一个组合，协同，方法来研究组织，两个- 界面处的三维生物膜结构。的具体目标 联合收割机是将生物化学的方法， 表面化学和振动光谱，用于评估 生理学相关体外结构/功能关系 肺表面活性物质的模型。 这种结合的研究方法将使用生物化学技术， 新发现的缩醛磷脂的分离和鉴定 肺表面活性物质的磷脂成分。经典朗缪尔- Blodgett表面化学技术将用于研究磷脂 表面活性剂模型复合物和孤立材料中单层结构 天然肺表面活性剂这些实验，除了 在生理学上监测磷脂顺序和相互作用 相关国家，将直接测试“挤出”假说， 表面活性剂铺展，即表面活性剂一种特殊组分 在连续的压缩循环期间在表面富集， 以产生接近零的表面张力。红外光谱将是 用于确定这些生物膜模型的分子构象 通过衰减全反射方法在固体载体上，和在- 在空气-水界面上通过外反射法原位测量。我们将 监测Ca 2+依赖性磷脂构象，蛋白质二级 结构和取向的有序肽段在朗缪尔- Blodgett脂质-肽膜的红外光谱法。这种方法将 提供了关于分子之间相互作用的分子性质的会费， 磷脂、Ca 2+和表面活性剂蛋白质。我们将研究其结构 肺表面活性物质SP-B和SP-C的空间分布 使用这些振动光谱法， 方法与表面化学技术相结合。我们将进一步 开发一种新的方法，用于获得增强的生物物理红外光谱 单层膜原位在空气-水界面，并将特别 将此方法应用于表面活性肽相互作用的研究 用磷脂单层。 一种新的振动光谱方法 也将用于识别二维微域 分离的二元混合物用作生物膜模型。的 这些技术在体外模型系统上的组合有望 大大提高了我们对结构和反应性的理解， 体内天然肺表面活性剂。

The general, long-term goal of the research described in this proposal is to use a combined, synergistic, approach to study organized, two- dimensional biomembrane structures at interfaces. The specific objectives of this research project are to combine the methods of biochemistry, surface chemistry, and vibrational spectroscopy for evaluation of structure/function relationships in physiologically relevant in-vitro models for pulmonary lung surfactant. This combined research approach will use biochemical techniques for the isolation and characterization of the newly-discovered plasmalogen phospholipid component of pulmonary surfactant. Classical Langmuir- Blodgett surface chemistry techniques will be used to study phospholipid monolayer structure in surfactant model complexes and in isolated material from native pulmonary surfactant. These experiments, in addition to monitoring phospholipid order and interactions in a physiologically relevant state, will directly test the "squeezing-out" hypothesis of surfactant spreading, namely that one particular component of surfactant becomes enriched at the surface during successive compression cycles, in order to produce near-zero surface tension. Infrared spectroscopy will be used to determine the molecular conformation of these biomembrane models both on solid supports via attenuated total reflectance methods, and in- situ at the air-water interface by external reflectance methods. We will monitor the Ca2+-dependent phospholipid conformation, protein secondary structure, and orientation of ordered peptide segments in Langmuir- Blodgett lipid-peptide films by infrared spectroscopy. This approach will provide dues as to the molecular nature of the interactions between phospholipids, Ca2+, and surfactant proteins. We will study the structure and spatial distribution of the pulmonary surfactant SP-B and SP-C peptides in bilayer ultrathin films using these vibrational spectroscopic methods in combination with surface chemistry techniques. We will further develop a new method for obtaining enhanced IR spectra of biophysical monolayer films in-situ at the air-water interface, and will particularly apply this method to the study of the interaction of surfactant peptides with phospholipid monolayers. A new vibrational spectroscopy approach will also be used in order to identify the two-dimensional micro-domain segregation in binary mixtures used as ultrathin biomembrane models. The combination of these techniques on in-vitro model systems promises to significantly improve our understanding of the structure and reactivity of native pulmonary surfactant in-vivo.