Yamamoto Masaki, Hirata Kunio, Yamashita Keitaro, Hasegawa Kazuya, Ueno Go, Ago Hideo, Kumasaka Takashi
Advanced Photon Technology Division, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
IUCrJ. 2017 Aug 8;4(Pt 5):529-539. doi: 10.1107/S2052252517008193. eCollection 2017 Sep 1.
The progress in X-ray microbeam applications using synchrotron radiation is beneficial to structure determination from macromolecular microcrystals such as small crystals. However, the high intensity of microbeams causes severe radiation damage, which worsens both the statistical quality of diffraction data and their resolution, and in the worst cases results in the failure of structure determination. Even in the event of successful structure determination, site-specific damage can lead to the misinterpretation of structural features. In order to overcome this issue, technological developments in sample handling and delivery, data-collection strategy and data processing have been made. For a few crystals with dimensions of the order of 10 µm, an elegant two-step scanning strategy works well. For smaller samples, the development of a novel method to analyze multiple isomorphous microcrystals was motivated by the success of serial femtosecond crystallography with X-ray free-electron lasers. This method overcame the radiation-dose limit in diffraction data collection by using a sufficient number of crystals. Here, important technologies and the future prospects for microcrystallography are discussed.
同步辐射X射线微束应用的进展有利于从小晶体等大分子微晶中确定结构。然而，微束的高强度会导致严重的辐射损伤，这会使衍射数据的统计质量及其分辨率都变差，在最坏的情况下会导致结构确定失败。即使在成功确定结构的情况下，位点特异性损伤也可能导致对结构特征的错误解读。为了克服这个问题，在样品处理与输送、数据收集策略和数据处理方面都取得了技术进展。对于一些尺寸约为10 µm的晶体，一种精巧的两步扫描策略效果良好。对于更小的样品，受X射线自由电子激光的串行飞秒晶体学成功的推动，一种分析多个同晶型微晶的新方法得以发展。该方法通过使用足够数量的晶体克服了衍射数据收集时的辐射剂量限制。在此，讨论微晶学的重要技术和未来前景。
