Biological Membranes and Atomic Force Microscopy

生物膜和相关系统正在研究通过原子力显微镜（AFM），拉曼光谱，和其他生物物理方法的项目，涉及几个合作。 (1)我们继续与牛水琳博士（NIAAA，NIH），B。J. Litman（NIAAA，NIH）及其同事，使用原子力显微镜（AFM）以亚纳米分辨率表征视紫红质蛋白（视觉通路的G蛋白偶联受体（GPCR））在天然视杆外节膜和重构脂质膜中的结构和功能。为了进一步揭示视紫红质分子的组织结构，并探讨视紫红质信号和脂质膜环境之间的联系，我们介绍了一种新的拉曼光谱仪器，基于非弹性激光光子散射，用于蛋白质和脂质的鉴定和结构。我们正在优化拉曼检测灵敏度对单双层纳米域表征。 (2)我们与Ralph Nossal博士（NICHD，NIH）和Eileen M. Lafer和K.普拉萨德（德克萨斯大学，圣安东尼奥）。CCV是重要的生物膜和多蛋白复合物，其在受体介导的内吞作用、来自trans-Golgi网络的细胞内运输和整体细胞功能中发挥核心作用。力学性能提取我们新的AFM测量方案，生物物理建模和数据分析方法。我们发现完整的CCV的抗弯刚度大约是其构成外部网格蛋白多面体晶格和内部磷脂膜的20倍。这表明天然CCV中的衔接蛋白层在其网格蛋白外壳和具有分子货物的内脂质膜之间提供了部分且因此可变的偶联。 (3)随着一些校内和校外的科学家，我们继续扩大我们的研究和开发工作，涉及原子力显微镜，光谱学，生物物理数据分析，纳米技术和相关方法。这些工作包括纳米粒子和碳纳米管在单分子检测，单蛋白质力学和生物医学研究和诊断中的潜在应用。我们希望我们在拉曼和光学光谱学方面的新投资能够显著扩展我们在纳米和微米技术开发和应用方面的能力。

Biological membranes and related systems are being investigated via atomic force microscopy (AFM), Raman spectroscopy, and other biophysical approaches in projects involving several collaborations. (1) We continue our collaboration with Drs. Shui-Lin Niu (NIAAA, NIH), B. J. Litman (NIAAA, NIH) and colleagues, using atomic force microscopy (AFM) to characterize at sub-nanometer resolutions structure and function of the protein rhodopsin, a G-protein coupled receptor (GPCR) of the visual pathway, in native rod outer segment membranes and in reconstituted lipid membranes. To further reveal rhodopsin molecule organization and to explore the connection between rhodopsin signaling and the lipid membrane environment, we have introduced a new Raman spectroscopy instrument, based on inelastic laser photon scattering, for protein and lipid identification and structure. We are optimizing the Raman detecting sensitivity toward single bilayer nanometric domain characterizations. (2) We have completed a new AFM study of clathrin coated vesicles (CCVs) in collaboration with Dr. Ralph Nossal (NICHD, NIH) and Drs. Eileen M. Lafer and K. Prasad (University Texas, San Antonio). CCVs are important biological membrane and multi-protein complexes that play a central role in receptor-mediated endocytosis, intracellular trafficking from the trans-Golgi network, and overall cellular functions. The mechanical properties were extracted from our new AFM measurement scheme, biophysical modeling, and data analysis methods. We showed that the bending rigidity of intact CCVs is about 20 times that of its constituting outer clathrin polyhedral lattice and inner phospholipids membrane. This suggests that the adaptor protein layer in native CCVs provides a partial, and thus changeable, coupling between its clathrin coat and the inner lipid membrane with molecular cargo. (3) With a number of intramural and extramural scientists, we continue to expand our research and development effort involving AFM, spectroscopy, biophysical data analyses, nanotechnology, and related methods. These include works on nanoparticles and carbon nanotubes with potential applications in single molecule detection, single protein mechanics, and biomedical research and diagnostics. We expect our new investment in Raman and optical spectroscopy to extend significantly our capabilities in nano- and micro-technological development and applications.