Making routine native SAD a reality: lessons from beamline X06DA at the Swiss Light Source
Making routine native SAD a reality: lessons from beamline X06DA at the Swiss Light Source
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DOI：
10.1107/s2059798319003103
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发表时间：
2019-03-01
影响因子：
2.2
通讯作者：
Olieric, Vincent
中科院分区：
文献类型：
--
作者：
Basu, Shibom;Finke, Aaron;Olieric, Vincent
自然单波长反常色散（SAD）是大分子晶体学中最有吸引力的从头定相方法，因为它直接利用自然晶体的固有反常散射。然而，这种实验的成功取决于对反射强度的准确测量，因此也取决于仔细的数据收集协议。在这里，低剂量，多方位的数据收集协议本地SAD定相开发的光束线X 06 DA（PXIII）在瑞士光源进行审查，并在过去四年中，其使用常规晶体（>50 μ m）的报告。由于实验上非常简单和快速，这种方法已经得到了普及，并提供了45个从头结构（其中13个已发表）。原生SAD目前是X 06 DA用户进行实验性阶段调整的主要选择。该方法可以解决具有挑战性的情况：在这里，突出显示了在具有P2（1）对称性和0.6%的低Bijvoet比率的链霉亲和素-生物素晶体上进行的天然SAD定相。使用的内在异常信号作为序列标记的模型的建立和分配的离子也简要介绍。
Native single-wavelength anomalous dispersion (SAD) is the most attractive de novo phasing method in macromolecular crystallography, as it directly utilizes intrinsic anomalous scattering from native crystals. However, the success of such an experiment depends on accurate measurements of the reflection intensities and therefore on careful data-collection protocols. Here, the low-dose, multiple-orientation data-collection protocol for native SAD phasing developed at beamline X06DA (PXIII) at the Swiss Light Source is reviewed, and its usage over the last four years on conventional crystals (>50 mu m) is reported. Being experimentally very simple and fast, this method has gained popularity and has delivered 45 de novo structures to date (13 of which have been published). Native SAD is currently the primary choice for experimental phasing among X06DA users. The method can address challenging cases: here, native SAD phasing performed on a streptavidin-biotin crystal with P2(1) symmetry and a low Bijvoet ratio of 0.6% is highlighted. The use of intrinsic anomalous signals as sequence markers for model building and the assignment of ions is also briefly described.