Chapman Michael S, Somasundaram Thayumanasamy
Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health and Science University, Portland, OR 97239-3098, USA.
Acta Crystallogr D Biol Crystallogr. 2010 Jun;66(Pt 6):741-4. doi: 10.1107/S0907444910012436. Epub 2010 May 15.
Macromolecular structures are routinely determined at cryotemperatures using samples flash-cooled in the presence of cryoprotectants. However, sometimes the best diffraction is obtained under conditions where ice formation is not completely ablated, with the result that characteristic ice rings are superimposed on the macromolecular diffraction. In data processing, the reflections that are most affected by the ice rings are usually excluded. Here, an alternative approach of subtracting the ice diffraction is tested. High completeness can be retained with little adverse effect upon the quality of the integrated data. This offers an alternate strategy when high levels of cryoprotectant lead to loss of crystal quality.
大分子结构通常是在低温下使用在冷冻保护剂存在下快速冷却的样品来确定的。然而，有时在冰形成没有完全消除的条件下可获得最佳衍射，结果是特征冰环叠加在大分子衍射上。在数据处理中，通常会排除受冰环影响最大的反射。在此，测试了一种减去冰衍射的替代方法。可以保留高完整性，而对积分数据的质量几乎没有不利影响。当高浓度的冷冻保护剂导致晶体质量损失时，这提供了一种替代策略。
