HIGH RESOLUTION IMAGING WITH CARBON NANOTUBE PROBES

描述（改编自申请人的摘要）： 蛋白质、核酸和这些大分子的组合体提供了 对理解并最终实现控制至关重要的信息 生物功能。原子力显微镜（AFM）是一种强大的技术， 已经被用来探测生物系统的结构和动力学， 从而可以显著地推进生物学功能的知识。水平 原子力显微镜图像中的信息量的大小，形状和终端 用于成像的尖端的功能。商业提示显示， 令人印象深刻的分辨率，但较低的分辨率， 分离的蛋白质，并可以显示显着的尖端到尖端的变化， 分辨率为了克服现有技巧的局限性，更好地利用 潜力的原子力显微镜，本研究将集中在发展和 碳纳米管探针的应用。碳纳米管有几个特点 这使得它们成为结构生物学的理想选择，包括高纵横比 用于成像深和窄的特征，潜在分辨率优于0.5 纳米。此外，纳米管的明确分子结构应该 能够合成相同尺寸和分辨率的尖端， 修饰纳米管末端，用于具有化学敏感性的成像。 该项目的总体目标是制定所需的方法， 制备具有可再现的纳米结构分辨率的碳纳米管尖端， 开发用于功能成像的修饰纳米管末端的方法， 利用碳纳米管尖端来阐明染色质的机制， SWI/SNF和其他复合物的重塑。金属催化化学气相 沉积将用于合成，从而直接控制碳 纳米管尖端。纳米管尖端的电子显微镜成像和 将使用具有相同提示的标准和蛋白质模型系统来定义 合成、结构和分辨率之间的关系。化学 反应将被用来定位探针物种，包括基本的有机 官能团和更复杂的配体，在纳米管尖端的末端。的 在化学上不同的残基作图中修饰的探针的分辨率， 结合位点将使用单层、双层和蛋白质系统来定义。 碳纳米管针尖将用于确定产物的结构 由单核细胞的ATP依赖性SWI/SNF重塑产生， 多核小体，研究SWI/SNF复合物的结构，分析 高级染色质结构在重塑中的作用， 通过核小体重塑脱乙酰酶复合物进行重塑。

DESCRIPTION (adapted from applicant's abstract): Elucidating the structure of proteins, nucleic acids, and assemblies of these macromolecules provides information critical to understanding and ultimately enabling the control of biological function. Atomic force microscopy (AFM) is a powerful technique that has been utilized to probe the structure and dynamics of biological systems, and thus can advance significantly knowledge of biological function. The level of information in AFM images depends critically on the size, shape and terminal functionality of the tips used for imaging. Commercial tips have exhibited impressive resolution on packed molecular arrays but lower resolution on isolated proteins, and can show significant tip-to-tip variations in resolution. To overcome limitations of present tips and better exploit the potential of AFM, the present study will focus on the development and application of carbon nanotube probes. Carbon nanotubes have several features that make them ideal for structural biological, including high aspect ratios for imaging deep and narrow features and potential resolution better than 0.5 nanometers. Moreover, the well-defined molecular structure of nanotubes should enable the synthesis of identical size and resolution tips, and the modification of nanotube ends for imaging with chemical sensitivity. The overall aims of this project are to develop the methodologies needed to prepare carbon nanotube tips with reproducible ultrahigh structural resolution, to develop approaches for modifying nanotubes ends for functional imaging, and to exploit carbon nanotube tips to elucidate the mechanism of chromatin remodeling by SWI/SNF and other complexes. Metal-catalyzed chemical vapor deposition will be used to synthesize and thereby directly control the carbon nanotube tips. Electron microscopy imaging of nanotube tips and AFM imaging of standards and protein model systems with the same tips will be used to define the relationships between synthesis, structure and resolution. Chemical reactions will be used to localize probe species, including basic organic functional groups and more complex ligands, at the ends of nanotube tips. The resolution of the modified probes in mapping chemically-distinct residues and binding sites will be defined using monolayer, bilayer and protein systems. Carbon nanotube tips will be used to determine the structures of the products produced by ATP-dependent SWI/SNF remodeling of mononucleosomes and polynucleosomes, to study the structure(s) of the SWI/SNF complex, to analyze the role that higher order chromatin structure has on remodeling, and to study remodeling by nucleosome remodeling deacetylase complex.