Glycophorin A Dimers to Probe Membranes: A 2D-IR Study

2D-IR实验研究了跨膜的平衡结构和动力学 蛋白血型糖蛋白A（GpA）在几种脂质双层环境。血型糖蛋白A通过弱的 货车范德华力和CaH. O氢键。预计这些弱关联很容易被 随着环境的改变而改变。因此，2D-IR研究检查了 相反链上的残基将揭示有关GpA结构如何随着 环境变化。将研究几种脂质双层，包括二肉豆蔻酰磷脂酰胆碱（DMPC） 膜囊泡和DMPC/胆固醇囊泡，以探测脂质组成如何影响结构， 从而发挥跨膜蛋白的功能。这项工作将测试假设的作用，脂质 蛋白质结构上的微区或“筏”。单频和双频二维红外光子回波实验将 在不同的脂质相中对同位素标记的GpA进行，以确定哪种相互作用最重要。 对环境敏感。 跨膜蛋白不容易通过常规技术探测，并且 膜组成对跨膜结构和功能的影响尚不清楚。由于许多 对细胞功能至关重要的跨膜蛋白，了解膜环境之间的相互作用 蛋白质结构是非常重要的。

2D-IR experiments are proposed to study the equilibrium structure and dynamics of the transmembrane protein Glycophorin A (GpA) in several lipid bilayer environments. Glycophorin A dimerizes through weak van der Waals forces and CaH...O hydrogen bonds. It is expected that these weak associations are easily disrupted as the environment is changed. Thus, 2D-IR studies examining the interactions between the residues on opposite strands will reveal information about how the structure of GpA changes as the environment changes. Several lipid bilayers will be studied, both a dimyristoylphosphatidylcholine (DMPC) membrane vesicle and a DMPC/cholesterol vesicle, to probe how lipid composition influences the structure, and thus function, of transmembrane protein. This work will test hypotheses about the role of lipid microdomains or "rafts" on protein structure. Single and Dual Frequency 2D-IR photon echo experiments will be performed on isotopically labeled GpA in different lipid phases to determine which interactions are most sensitive to environment. Transmembrane proteins are not easily probed by conventional techniques, and the influence of membrane composition on transmembrane structure and function is not well understood. Since many transmembrane proteins critical to cell function, understanding the interplay between membrane environment and protein structure is vitallv important.