Radiation damage in small-molecule crystallography: fact not fiction
Radiation damage in small-molecule crystallography: fact not fiction
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DOI：
10.1107/s2052252519006948
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发表时间：
2019-07-01
期刊：
影响因子：
3.9
通讯作者：
Coles, Simon J.
中科院分区：
文献类型：
--
作者：
Christensen, Jeppe;Horton, Peter N.;Coles, Simon J.
传统上，小分子晶体学家在衍射实验中通常没有观察到或认识到样品的显著辐射损伤。然而，由第三代同步加速器提供的增加的通量密度导致了对这种现象的越来越多的观察。小分子系统类型的多样性意味着还不可能提出辐射诱导样品衰减的一般机制，但是对效应的表征将允许尝试理解和减轻它。在这里，系统的实验报告了样品温度和光束衰减对辐射损伤进展的影响，允许定性和定量评估它们对小分子测试样品的晶体的影响。为了允许不同测量的相互比较，辐射损伤度量（衍射强度下降、分辨率下降、缩放B因子增加）相对于吸收剂量作图。为了便于剂量计算，为蛋白质晶体学开发的软件RADDOSE-3D已被修改用于小分子晶体学。这些初步实验旨在帮助小分子晶体学家建立方案，以便在辐射损伤的有害影响开始之前优化样品的衍射信号。
Traditionally small-molecule crystallographers have not usually observed or recognized significant radiation damage to their samples during diffraction experiments. However, the increased flux densities provided by third-generation synchrotrons have resulted in increasing numbers of observations of this phenomenon. The diversity of types of small-molecule systems means it is not yet possible to propose a general mechanism for their radiation-induced sample decay, however characterization of the effects will permit attempts to understand and mitigate it. Here, systematic experiments are reported on the effects that sample temperature and beam attenuation have on radiation damage progression, allowing qualitative and quantitative assessment of their impact on crystals of a small-molecule test sample. To allow inter-comparison of different measurements, radiation-damage metrics (diffraction-intensity decline, resolution fall-off, scaling B-factor increase) are plotted against the absorbed dose. For ease-of-dose calculations, the software developed for protein crystallography, RADDOSE-3D, has been modified for use in small-molecule crystallography. It is intended that these initial experiments will assist in establishing protocols for small-molecule crystallographers to optimize the diffraction signal from their samples prior to the onset of the deleterious effects of radiation damage.