Structure-factor analysis of femtosecond micro-diffraction patterns from protein nanocrystals
Structure-factor analysis of femtosecond micro-diffraction patterns from protein nanocrystals
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DOI：
10.1107/s0108767310050981
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发表时间：
2011-03-01
期刊：
影响因子：
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通讯作者：
Spence, John C. H.
中科院分区：
文献类型：
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作者：
Kirian, Richard A.;White, Thomas A.;Spence, John C. H.
一套完整的结构因子已被提取从成千上万的飞秒单次拍摄的X射线显微衍射图案随机取向的纳米晶体。Monte Carlo积分的方法在微晶的大小和取向适用于从光系统I纳米晶体的实验数据。这到达结构因子从许多部分反射没有事先知道的颗粒尺寸分布。数据是在直线加速器相干光源（第一个硬X射线激光用户设施）收集的，根据连续晶体学方法，该光源安装有水合蛋白质凝胶注射器射流。这些数据是单一的“静止”衍射快照，每个来自不同的晶体，尺寸范围在100 nm和2 μ m之间，因此布拉格峰的角宽度主要由晶体尺寸效应决定。这些结果进行了比较与单晶数据记录从大晶体的光系统I在先进的光源和数据的质量被发现是相似的。通过允许使用非常小的晶体，减少辐射损伤和时间分辨衍射研究在室温下提高数据收集效率的影响进行了讨论。
A complete set of structure factors has been extracted from hundreds of thousands of femtosecond single-shot X-ray microdiffraction patterns taken from randomly oriented nanocrystals. The method of Monte Carlo integration over crystallite size and orientation was applied to experimental data from Photosystem I nanocrystals. This arrives at structure factors from many partial reflections without prior knowledge of the particle-size distribution. The data were collected at the Linac Coherent Light Source (the first hard-X-ray laser user facility), to which was fitted a hydrated protein nanocrystal injector jet, according to the method of serial crystallography. The data are single 'still' diffraction snapshots, each from a different nanocrystal with sizes ranging between 100 nm and 2 mu m, so the angular width of Bragg peaks was dominated by crystal-size effects. These results were compared with single-crystal data recorded from large crystals of Photosystem I at the Advanced Light Source and the quality of the data was found to be similar. The implications for improving the efficiency of data collection by allowing the use of very small crystals, for radiation-damage reduction and for time-resolved diffraction studies at room temperature are discussed.