LIPID AND PROTEIN EFFECTS ON MONOLAYER STABILITY

脂质和蛋白质对单层稳定性的影响

• 批准号: 6490551
• 负责人: Joseph Anthony Zasadzinski
• 金额: $ 23.47万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA BARBARA
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6490551
• 关键词: X ray crystallography; atomic force microscopy; biophysics; biotechnology; blood proteins; chemical structure function; combinatorial chemistry; fluorescence microscopy; intermolecular interaction; lipid solubility; lipid structure; molecular assembly /self assembly; molecular film; peptide chemical synthesis; phase change; phospholipids; protein folding; protein structure function; proteins; pulmonary surfactants; respiratory distress syndrome of newborn; serum albumin; surface property; synthetic protein; viscosity

Developing new surfactant substitutes requires (1) understanding the roles of the lipids and proteins in native lung surfactant; (2) developing easy to synthesize analogs of the native surfactant proteins; (3) optimizing lipid composition for low surface tension and rapid respreading and adsorption; (4) understanding surfactant inhibition by serum proteins and optimizing surfactant composition to minimize this inhibition. We will use modern biophysical techniques including Langmuir isotherms, fluorescence and Brewster angle optical microscopy, atomic force microscopy, viscometry, and x-ray diffraction to determine the phase behavior and morphology of lung surfactants. Specifically: (1) SP-B eliminates squeeze-out of unsaturated lipids and makes monolayer collapse more reversible. SP-C is more efficient at eliminating squeeze-out, and is less efficient at altering collapse. Is there an optimal ratio of SP-B to SP-C, or are the proteins interchangable? (2) Can we make a better SP-B and/or SP-C? Based on the known amino acid sequences of SP-B and SP-C, we will synthesize a family of homodimer peptides that mimic the characteristics of SP-B and SP-C. (3) Is there an optimal solid phase fraction in surfactant monolayers? Adding palmitic acid (PA) to DPPC influences the fluid to solid phase transitions and helps lower the surface tension. We plan to determine the composition of the solid phase in model surfactants and Survanta. (4) What leads to surfactant inhibition by serum proteins? Blood, plasma and serum proteins, lysolipids, and meconium may compete for interfacial area or might solubilize or degrade constituents of surfactant, thereby impairing monolayer function. We propose to investigate the interaction of model lung surfactant mixtures with human serum albumin to determine the molecular mechanisms of surfactant inhibition. (S) Can we relate monolayer viscosity to monolayer morphology and composition? We have built a magnetic needle viscometer to carry out systematic studies of LS monolayer shear viscoelasticity as a function of: i) protein content; ii) phase state of the monolayer. Concurrently, an existing double-barrier Langmuir trough will be adapted to do dilational viscoelasticity under the same conditions.

开发新的表面活性剂替代品需要（1）了解脂质和蛋白质在天然肺表面活性剂中的作用； （2）开发易于合成天然表面活性剂蛋白的类似物； （3）优化低表面张力和快速重新启动和吸附的脂质组成； （4）了解血清蛋白抑制表面活性剂并优化表面活性剂组成以最大程度地减少这种抑制作用。我们将使用现代的生物物理技术，包括Langmuir等温线，荧光和BREWSTER角度显微镜，原子力显微镜，粘度测定和X射线衍射来确定肺表面活性剂的相行为和形态。具体来说：（1）SP-B消除了不饱和脂质的挤出，使单层塌陷更可逆。 SP-C在消除挤压方面更有效，并且在改变崩溃方面的效率较低。 SP-B与SP-C的最佳比率，还是蛋白质可互换？ （2）我们可以做一个更好的SP-B和/或SP-C吗？基于SP-B和SP-C的已知氨基酸序列，我们将合成一个模仿SP-B和SP-C的特征的同二聚体肽家族。 （3）表面活性剂单层中是否有最佳的固相分数？添加棕榈酸（PA）以DPPC影响固体过渡的流体，并有助于降低表面张力。我们计划确定模型表面活性剂和Survanta中固相的组成。 （4）什么导致血清蛋白抑制表面活性剂？血液，血浆和血清蛋白，溶酶体和胎粪可能会竞争界面区域，或者可能溶解或降解表面活性剂的成分，从而损害单层功能。我们建议研究模型肺表面活性剂混合物与人血清白蛋白的相互作用，以确定表面活性剂抑制的分子机制。 （s）我们可以将单层粘度与单层形态和组成联系起来吗？我们已经建立了一个磁针粘度，以进行LS单层剪切粘弹性的系统研究：I）蛋白质含量； ii）单层的相状状态。同时，现有的双屏障Langmuir槽将适应在相同条件下进行扩张粘弹性。