New Approaches to Radiation Damage and Cryoprotection

描述（由申请人提供）：通过X射线晶体学确定的大分子结构对于现代生物学过程和疾病机制的理解以及新药的设计至关重要。由X射线本身和用于使辐射损伤最小化的低温保护程序引起的晶体损伤降低了结构分辨率和准确性-这对机理研究特别重要-并且在不利的情况下可以防止结构测定。强大的衍射和实空间成像技术最近已被用于解剖大分子晶体中的无序，并为理解这种损伤提供了新的工具。 该项目的长期目标是使用简单的模型蛋白质和病毒来表征辐射和冷冻保护引起的疾病的系统学;开发减少这种疾病的新程序，以便充分利用高亮度同步辐射源的数据收集潜力;并将其应用于具有重要生物学意义的选定系统。辐射损伤和闪冷引起的损伤是复杂的现象，没有单一因素可能产生显著的改善。使用X射线衍射和成像，原子力显微镜和其他技术的系统实验将评估最重要的因素，并探索如何将它们结合起来优化整体数据质量。这种方法具有重要和现实的潜力，影响如何确定大分子结构，从而有助于它们在医疗，制药和农业应用中的使用。

DESCRIPTION (provided by applicant): Macromolecular structures determined by X-ray crystallography are central to modern understanding of biological processes and disease mechanisms and to the design of new medicines. Crystal damage caused by the X-rays themselves and by the cryoprotective procedures used to minimize radiation damage reduces structure resolution and accuracy -- of particular importance to mechanistic studies -- and in unfavorable cases can prevent structure determination. Powerful diffraction and real-space imaging techniques have recently been used to dissect disorder in macromolecular crystals, and provide new tools for understanding this damage. The long term goals of this project are to characterize the systematics of radiation and cryoprotection-induced disorder using simple model proteins and viruses; to develop new procedures for reducing this disorder so that the full potential of high brilliance synchrotron sources for data collection can be exploited; and to apply these to selected systems of significant biological interest. Radiation damage and damage caused by flash cooling are complex phenomena, and no single factor is likely to produce dramatic improvements. Systematic experiments using X-ray diffraction and imaging, atomic force microscopy and other techniques will evaluate the most important factors, and explore how they may be combined to optimize overall data quality. This approach has significant and realistic potential to impact how macromolecular structures are determined, and thereby to contribute to their use in medical, pharmaceutical, and agricultural applications.