HIGH PRESSURE CRYOCOOLING AND RADIATION DAMAGE

高压低温冷却和辐射损伤

• 批准号: 7598558
• 负责人: SOL M GRUNER
• 金额: $ 2.8万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7598558
• 关键词: Biological; Chemicals; Computer Retrieval of Information on Scientific Projects Database; Condition; Crystallography; Diffusion; Free Radicals; Freezing; Funding; Grant; Ice; Institution; Methods; Proteins; Radiation; Research; Research Personnel; Resources; Sampling; Source; Temperature; Testing; United States National Institutes of Health; Viscosity; cryogenics; density; pressure

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Radiation damage to biological samples is currently one of the major limiting factors in macromolecular x-ray crystallography. One of the best known method to reduce radiation damage at room temperature is flash freezing crystals to cryogenic temperature, which often requires finding penetrating cryoprotectants. Recently a new crystal freezing method, high pressure cryocooling, was developed, where using of cryoprotectants was avoided by freezing crystals under high pressures (1000 ~ 2000 atm). The mechanism was suggested involving high density amorphous (HDA) ice which has density of 1.17 g/cm3 at ambient pressure. Since the secondary radiation damage highly depends on the diffusion of the free radicals produced by x-ray radiation, HDA ice might be effective to reduce radiation damage due to its high viscosity and density compared to low density amorphous ice that usually forms inside crystal at ambient pressure. We will test the effect of high pressure cryocooling on radiation damage. For the study, high quality protein crystals will be prepared at several different pressures(1 atm ~ 4000 atm) and different chemical conditions.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 对生物样品的辐射损害目前是大分子X射线晶体学的主要限制因素之一。减少室温下辐射损伤的最著名方法之一是将晶体闪烁到低温温度，这通常需要找到穿透性的冷冻保护剂。最近，开发了一种新的晶体冷冻方法，即高压冷冻冷却，在高压下（1000〜2000 atm）下，通过冷冻晶体来避免使用冷冻保护剂。建议该机理涉及高密度无定形（HDA）冰，该冰的密度在环境压力下为1.17 g/cm3。 由于次级辐射损伤高度取决于X射线辐射产生的自由基的扩散，因此与通常在环境压力下晶体内部形成的低密度无定形冰相比，HDA冰可能有效地减少辐射损伤。 我们将测试高压冷冻冷却对辐射损伤的影响。为了进行研究，高质量的蛋白质晶体将在几个不同的压力（1个大气压约4000 atm）和不同的化学条件下制备。