Until recently X-ray crystallography has been the standard technique for virus structure determinations. Available X-ray sources have continuously improved over the decades, leading to the realization of X-ray free-electron lasers (XFELs). They provide high-intensity femtosecond X-ray pulses, which allow for new kinds of experiments by making use of the diffraction-before-destruction principle. By overcoming classical dose constraints, they at least in principle allow researchers to perform X-ray virus structure determination for single particles at room temperature. Simultaneously, the availability of XFELs led to the development of the method of serial femtosecond crystallography, where a crystal structure is determined from the measurement of hundreds to thousands of microcrystals. In the case of virus crystallography this method does not require freezing of the crystals and allows researchers to perform experiments under non-equilibrium conditions (e.g., by laser-induced temperature jumps or rapid chemical mixing), which is currently not possible with electron microscopy.

中文翻译：

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X射线自由电子激光的病毒结构。

直到最近，X射线晶体学一直是确定病毒结构的标准技术。几十年来，可用的X射线源一直在不断改进，从而实现了X射线自由电子激光器（XFEL）。它们提供了高强度的飞秒X射线脉冲，从而可以利用“先衍射后衍射”原理进行新的实验。通过克服经典的剂量限制，它们至少在原则上至少允许研究人员在室温下对单个颗粒进行X射线病毒结构测定。同时，XFEL的可用性导致了串行飞秒晶体学方法的发展，该方法通过测量数百至数千个微晶来确定晶体结构。