Probing the Dimerization of Transmembrane Helices in Lipid Bilayers

膜蛋白二聚化是折叠和信号转导的基本步骤之一，由于缺乏一种合适的方法来探测模型双层环境中的二聚化，阻碍了膜蛋白二聚化的生物物理研究。在本项目中，PI将开发一种新的工具来探测脂质双分子层中的膜蛋白二聚化。她将测量糖蛋白A在脂质环境下二聚化的热力学，并将结果与之前在洗涤剂系统中的研究结果进行比较。要开发的方法需要组装表面附着的双层，包含具有相同取向的横向移动膜蛋白。荧光标记蛋白的二聚化将使用成像共振能量转移来测量。这个项目将产生在双层环境中GpA二聚化的热力学测量。从长远来看，该方法将成为剖析疏水环境中膜蛋白相互作用化学的一种新的有用工具。在复杂生物体中，大约20%的蛋白质与膜相关。尽管膜蛋白丰富且在细胞生命中发挥着关键作用，但我们对膜蛋白折叠和结构-功能关系的了解有限，远远落后于对可溶性蛋白的了解。在某种程度上，这是由于有限的生物物理工具，以充分探索膜蛋白功能的物理化学原理。例如，在天然类脂双分子层环境中，一种探测跨膜螺旋二聚化的方法仍然缺失。在这个项目中，PI将通过组装含有膜蛋白的表面接枝脂质双分子层来开发这种方法。二聚化将测量使用成像荧光技术。该项目将培养两名研究生，并提高目前在她的实验室进行研究的少数族裔学生的教育经验。

AbstractMCB 0315663Biophysical studies of membrane protein dimerization, one of the basic steps in folding and signal transduction, are hindered by the lack of an adequate method to probe dimerization in a model bilayer environment. In this project, the PI will develop a new tool for probing membrane protein dimerization in a lipid bilayer. She will measure the thermodynamics of Glycophorin A dimerization in a lipid environment, and compare the results to previous studies in detergent systems. The method to be developed requires the assembly of surface-attached bilayers containing laterally mobile membrane proteins with identical orientations. The dimerization of the fluorescently labeled proteins will be measured using imaging resonance energy transfer. This project will yield thermodynamic measurements of GpA dimerization in a bilayer environment. In the long term, the method will be a new useful tool in dissecting the chemistry of interactions within membrane proteins in hydrophobic environments. Approximately 20% of all proteins in complex organisms are membrane-associated. Despite their abundance and key roles in cell life, our knowledge of the folding and the structure-function relationship for membrane proteins is limited, and lags far behind that of soluble proteins. In part, this is due to limited biophysical tools to adequately probe the physical-chemical principles underlying membrane protein function. For instance, a method to probe the dimerization of transmembrane helices in the native-like lipid bilayer environment is still missing. In this project, the PI will develop such a method by assembling surface grafted lipid bilayers that contain membrane proteins. Dimerization will be measured using an imaging fluorescence technique. The PI will train two graduate students and enhance the educational experience of underrepresented minority students currently conducting research in her laboratory.