Wang Qisheng, Yu Feng, Cui Ying, Zhang Kunhao, Pan Qiangyan, Zhong Changyou, Liu Ke, Zhou Huan, Sun Bo, He Jianhua
Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
Rev Sci Instrum. 2017 Jul;88(7):073301. doi: 10.1063/1.4991682.
The macromolecular crystallography beamlines at third-generation synchrotron facilities play a central role in solving macromolecular crystal structures and also in understanding the biological function at molecular levels. The MX beamline BL17U at Shanghai Synchrotron Radiation Facility is a typical standard MX beamline with a focused beam size (H × V) of FWHM around 80 μm × 45 μm. However the protein samples brought to the beamline are down to 5-10 m from the important and challenging science project now. These samples require smaller size beam. In order to achieve the mini-size beamline, two mini-beam modes have been developed on BL17U: the pinhole-based mini-beam and the focused mini-beam by compound refractive lens (CRL). Compared to the pinhole-based mode, three times increase in flux is obtained by the CRL mode at a similar beam size. The flux gain obtained by the CRL needs to be considered for data collection strategies. It takes few minutes to switch the beamline from the normal to CRL mini-beam mode.
第三代同步辐射装置上的大分子晶体学光束线在解析大分子晶体结构以及从分子层面理解生物学功能方面发挥着核心作用。上海同步辐射装置的MX光束线BL17U是一条典型的标准MX光束线，其聚焦光束尺寸（水平×垂直）的半高宽约为80μm×45μm。然而，如今带到该光束线的蛋白质样品距离重要且具有挑战性的科学项目要求还差得远。这些样品需要尺寸更小的光束。为了实现微型光束线，BL17U上开发了两种微型光束模式：基于针孔的微型光束和通过复合折射透镜（CRL）实现的聚焦微型光束。与基于针孔的模式相比，在类似光束尺寸下，CRL模式的通量提高了两倍。在数据收集策略中需要考虑CRL所获得的通量增益。将光束线从正常模式切换到CRL微型光束模式只需几分钟。
