Methods for Analysis of Helical Macromolecular Complexes

螺旋高分子复合物的分析方法

• 批准号: 6847746
• 负责人: EDWARD H. EGELMAN
• 金额: $ 22.2万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6847746
• 关键词: bioimaging /biomedical imaging; chemical structure function; computer human interaction; computer program /software; computer system design /evaluation; electron microscopy; image processing; macromolecule; method development; polymers; three dimensional imaging /topography

DESCRIPTION (provided by applicant): Many important biological macromolecules exist as helical polymers. Examples are actin, tubulin, myosin, RecA, Rad51, flagellin, pill, and bacteriophage tails. The first application of three-dimensional reconstruction from electron microscopic images was to a helical polymer, and several laboratories today are using helical tubes of integral membrane proteins as specimens for solving the near-atomic structure of these proteins in the electron microscope. The existing methods for image analysis and three-dimensional reconstruction of helices require that the structure be very regular. Unfortunately, many of these helical polymers are quite disordered. This may mean that only the most ordered polymers will be studied with existing methods. But the disorder that is present in the other specimens, those that cannot be studied, may have a large biological role in the function of these assemblies, so many interesting systems may not lend themselves to methodologies that require near-crystalline order. Further, perhaps the most interesting aspects of the structure and dynamics of more regular polymers may be obscured when helical averaging is imposed upon a specimen that may have significant deviations from such a regular symmetry. Over the past year an iterative method has been developed in my lab for the application of single-particle image processing techniques to disordered helical polymers, and applied very successfully to actin and nucleoprotein filaments involved in homologous genetic recombination. Intensive development work needs to be done to allow this methodology to be widely used in other laboratories. Further, there are preliminary indications of how the methodology can be extended to make it more powerful in separating out different structural states within a population of polymers. This project is devoted to improving this methodology, and producing a set of tools that can be easily used by other investigators. It is expected that the availability of such tools will have a large impact in fields such as cell biology, molecular biology and structural biology.

描述（由申请人提供）： 许多重要的生物大分子以螺旋聚合物的形式存在。例如肌动蛋白、微管蛋白、肌球蛋白、RecA、Rad51、鞭毛蛋白、pill和噬菌体尾。从电子显微镜图像进行三维重建的第一个应用是螺旋聚合物，今天有几个实验室正在使用完整膜蛋白的螺旋管作为样品，用于在电子显微镜中解决这些蛋白质的近原子结构。现有的图像分析和三维重建方法要求螺旋结构非常规则。不幸的是，许多这些螺旋聚合物是相当无序的。这可能意味着只有最有序的聚合物将与现有的方法进行研究。但是，在其他标本中存在的无序，那些无法研究的，可能在这些组件的功能中有很大的生物学作用，所以许多有趣的系统可能不适合需要近晶体秩序的方法。此外，也许是最有趣的方面的结构和动力学更经常的聚合物可能会被掩盖时，螺旋平均施加在一个标本，可能有显着的偏差，从这样一个经常对称。在过去的一年里，我的实验室已经开发出一种迭代方法，用于将单粒子图像处理技术应用于无序螺旋聚合物，并非常成功地应用于涉及同源遗传重组的肌动蛋白和核蛋白丝。需要进行深入的开发工作，以便使这种方法在其他实验室中广泛使用。此外，有初步迹象表明，该方法可以扩展，使其更强大的分离出不同的结构状态的人口的聚合物。该项目致力于改进这一方法，并制作一套其他调查人员可以轻松使用的工具。预计这些工具的可用性将在细胞生物学、分子生物学和结构生物学等领域产生巨大影响。