Project 3

3.3.背景和意义 3.3.1.迫切需要针对MP结构生物学优化的新型模型膜介质。绝大多数的MP结构确定到目前为止，无论是NMR或结晶学方法确定使用经典的洗涤剂作为模型膜介质。不幸的是，即使是温和的洗涤剂也会使MP相对于其在天然膜中的稳定性不稳定。此外，许多最温和的洗涤剂（如烷基麦芽糖苷）通常不能产生高质量的NMR谱。更天然的介质，如洗涤剂-脂质混合胶束或双胶束有时提供优点，但也有缺点。此外，虽然来自高等生物的膜几乎总是含有相当大的摩尔分数的胆固醇，但很少进行工作来建立含有胆固醇的NMR相容介质，部分原因是其在洗涤剂溶液中的溶解度非常低。显然，需要扩大可用的膜模拟介质的范围。我们建议设计，合成（通过核心B）和测试新的表面活性剂用于结构生物学研究的MP。我们还将测试表面活性剂 和胆固醇类似物，最近已经商业化，但尚未得到很好的测试。

3.3. Background and Significance 3.3.1. There is a compelling need for novel model membrane media that are optimized for MP structural biology. The vast majority of MP structures determined to date by either NMR or crystallographic methods were determined using classical detergent as the model membrane media. Unfortunately, even mild detergents destabilize MPs relative to their stability in native membranes. Moreover, many of the mildest detergents (such as the alkyl maltoside) routinely fail to yield high quality NMR spectra. More native-like media, such as detergent-lipid mixed micelles or bicelles sometimes offer advantages, but also have drawbacks. Moreover, while membranes from higher organisms almost always contain a considerable mole fraction of cholesterol, very little work has been carried out to establish NMR-compatible media that contain cholesterol, in part because of its very low solubility in detergent solutions. It is clear that there is a need to expand the range of membrane-mimetic media that are available. We propose to design, synthesize (through Core B) and test new surfactants for use in structural biological studies of MPs. We also will test surfactants and cholesterol analogs that have recently been commercialized but not yet well tested.