Facilitating model reconstruction for single-particle scattering using small-angle X-ray scattering methods

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• 作者：Shufen Ma and Haiguang Liu
• 关键词：X-ray free-electron lasers ; XFELs ; small-angle X-ray scattering ; protein structure ; single-particle imaging ; computer programs
• 刊名：Journal of Applied Crystallography
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：49
• 期：2
• 页码：665-671
• 全文大小：1029K
• ISSN：1600-5767

文摘

X-ray free-electron lasers generate intense femtosecond X-ray pulses, so that high-resolution structure determination becomes feasible from noncrystalline samples, such as single particles or single molecules. At the moment, the orientation of sample particles cannot be precisely controlled, and consequently the unknown orientation needs to be recovered using computational algorithms. This delays the model reconstruction until all the scattering patterns have been re-oriented, which often entails a long elapse of time and until the completion of the experiment. The scattering patterns from single particles or multiple particles can be summed to form a virtual powder diffraction pattern, and the low-resolution region, corresponding to the small-angle X-ray scattering (SAXS) regime, can be analysed using existing SAXS methods. This work presents a pipeline that converts single-particle data sets into SAXS data, from which real-time model reconstruction is achieved using the model retrieval approach implemented in the software package SASTBX [Liu, Hexemer & Zwart (2012). J. Appl. Cryst.45, 587–593]. To illustrate the applications, two case studies are presented with real experimental data sets collected at the Linac Coherent Light Source.