Structures from Anomalous Diffraction of Native Biological Macromolecules
Structures from Anomalous Diffraction of Native Biological Macromolecules
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DOI：
10.1126/science.1218753
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发表时间：
2012-05-25
期刊：
影响因子：
56.9
通讯作者：
Hendrickson, Wayne A.
中科院分区：
文献类型：
--
作者：
Liu, Qun;Dahmane, Tassadite;Hendrickson, Wayne A.
对没有已知结构相关物的生物大分子进行晶体结构分析需要解决晶体学相问题。典型的从头阶段评估取决于纳入比天然发现的更重的原子;最常见的是，多波长或单波长异常衍射（MAD或SAD）实验利用硒甲硫酰蛋白。在这里，我们实现了常规的结构测定使用固有的异常散射从本地大分子。我们设计了强大的程序，用于提高信号-噪声比在轻微的异常散射从一般的原生结构相结合的测量数据，从多个晶体在低于通常的X射线能量。使用这种多晶体SAD方法（5至13个等效晶体），我们确定了结构在中等分辨率（2.8至2.3埃）的天然蛋白质的大小（127至1148个独特的残基）和硫位点（3至28）的数量不同。由于不需要重原子掺入，这样的实验提供了一个有吸引力的替代硒甲硫酰SAD实验。
Crystal structure analyses for biological macromolecules without known structural relatives entail solving the crystallographic phase problem. Typical de novo phase evaluations depend on incorporating heavier atoms than those found natively; most commonly, multi- or single-wavelength anomalous diffraction (MAD or SAD) experiments exploit selenomethionyl proteins. Here, we realize routine structure determination using intrinsic anomalous scattering from native macromolecules. We devised robust procedures for enhancing the signal-to-noise ratio in the slight anomalous scattering from generic native structures by combining data measured from multiple crystals at lower-than-usual x-ray energy. Using this multicrystal SAD method (5 to 13 equivalent crystals), we determined structures at modest resolution (2.8 to 2.3 angstroms) for native proteins varying in size (127 to 1148 unique residues) and number of sulfur sites (3 to 28). With no requirement for heavy-atom incorporation, such experiments provide an attractive alternative to selenomethionyl SAD experiments.