Quantifying radiation damage in biomolecular small-angle X-ray scattering
Quantifying radiation damage in biomolecular small-angle X-ray scattering
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DOI：
10.1107/s1600576716005136
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发表时间：
2016-06-01
影响因子：
6.1
通讯作者：
Thorne, Robert E.
中科院分区：
文献类型：
--
作者：
Hopkins, Jesse B.;Thorne, Robert E.
小角X射线散射（SAXS）是一种越来越流行的技术，它提供了溶液中生物大分子的低分辨率结构信息。该技术的许多实际限制（例如最小所需样品体积）和实验设计（例如样品流动池）是必要的，因为生物样品对来自X射线的损伤敏感。辐射损伤通常表现为样本的聚集，这使得收集的数据不可靠。然而，一直很少有最有效的方法，以减少损坏率的系统调查，从以前的损坏研究的结果是不容易与其他光束线的结果相比。这里提供了一种方法，用于量化SAXS中的辐射损伤，以提供不同实验、实验者和光束线之间的一致结果。这些方法证明从溶菌酶，葡萄糖异构酶和木聚糖酶收集的辐射损伤数据，它被发现，没有一个单一的度量是足以描述所有样品的辐射损伤在SAXS。回转半径、分子量和积分SAXS谱强度构成了捕获所有类型的观察到的行为的最小参数集。从这些参数得到的辐射敏感性显示出很大的蛋白质依赖性，不同的蛋白质之间的测试高达六个数量级的变化。这项工作应有助于对辐射损害的影响作出一致的报告，从而能够对最有效的尽量减少辐射的战略进行更系统的研究。
Small-angle X-ray scattering (SAXS) is an increasingly popular technique that provides low-resolution structural information about biological macromolecules in solution. Many of the practical limitations of the technique, such as minimum required sample volume, and of experimental design, such as sample flow cells, are necessary because the biological samples are sensitive to damage from the X-rays. Radiation damage typically manifests as aggregation of the sample, which makes the collected data unreliable. However, there has been little systematic investigation of the most effective methods to reduce damage rates, and results from previous damage studies are not easily compared with results from other beamlines. Here a methodology is provided for quantifying radiation damage in SAXS to provide consistent results between different experiments, experimenters and beamlines. These methods are demonstrated on radiation damage data collected from lysozyme, glucose isomerase and xylanase, and it is found that no single metric is sufficient to describe radiation damage in SAXS for all samples. The radius of gyration, molecular weight and integrated SAXS profile intensity constitute a minimal set of parameters that capture all types of observed behavior. Radiation sensitivities derived from these parameters show a large protein dependence, varying by up to six orders of magnitude between the different proteins tested. This work should enable consistent reporting of radiation damage effects, allowing more systematic studies of the most effective minimization strategies.