Spectacular improvement of X-ray diffraction through fast desiccation of protein crystals
Spectacular improvement of X-ray diffraction through fast desiccation of protein crystals
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DOI：
10.1107/s0907444904013678
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发表时间：
2004-08-01
影响因子：
2.2
通讯作者：
Abergel, C
中科院分区：
文献类型：
--
作者：
Abergel, C
成功地使蛋白质结晶并不总是确定其三维结构的最后障碍。一种相对常见且特别令人烦恼的情况是产生宏观上良好形成的晶体，其没有显示出合适的衍射图案。在本文中，三个独立的情况下（即蛋白质和结晶条件）报告的壮观的衍射图案的改进，通过一个简单的晶体处理程序，是偶然发现的。该程序基本上包括从X射线束中取出无衍射的冷冻晶体，将其投入由补充有传统冷冻保护剂的原始结晶溶液制成的浸泡溶液中，然后使其在蒸发坐滴中干燥一段时间（15分钟至数小时）。处理后的晶体，然后重新安装，并表现出巨大的改善，其衍射强度和分辨率。在这里介绍的所有三种情况下，晶体质量从无法使用转变为完全适合结构测定。除了是与非衍射晶体斗争的实验学家的“最后手段”程序之外，这种令人困惑的效应对理论蛋白质晶体学家构成了一个更具挑战性的问题。
Succeeding in getting a protein to crystallize is not always the final hurdle in the determination of its three-dimensional structure. A relatively frequent and particularly vexing situation is the production of macroscopically well formed crystals that exhibit no suitable diffraction pattern. In this paper, three independent cases (i.e. proteins and crystallization conditions) are reported of spectacular diffraction-pattern improvement through a simple crystal-handling procedure that was discovered serendipitously. The procedure basically consists of removing a non-diffracting frozen crystal from the X-ray beam, plunging it into a soaking solution made of the original crystallization solution supplemented with a traditional cryoprotectant and then letting it dry in the evaporating sitting drop for some time ( 15 min to several hours). The treated crystals are then remounted and exhibit a huge improvement in their diffraction intensity and resolution. In all three cases presented here, the crystal quality shifted from unusable to perfectly suitable for structure determination. In addition to being a 'last resort' procedure for experimentalists struggling with non-diffracting crystals, this puzzling effect constitutes one more challenging problem for theoretical protein crystallographers.