A Bright Future for Serial Femtosecond Crystallography with XFELs. Issue 9 (September 2017) - Johansson, Linda C.
Abstract : X-ray free electron lasers (XFELs) have the potential to revolutionize macromolecular structural biology due to the unique combination of spatial coherence, extreme peak brilliance, and short duration of X-ray pulses. A recently emerged serial femtosecond (fs) crystallography (SFX) approach using XFEL radiation overcomes some of the biggest hurdles of traditional crystallography related to radiation damage through the diffraction-before-destruction principle. Intense fs XFEL pulses enable high-resolution room-temperature structure determination of difficult-to-crystallize biological macromolecules, while simultaneously opening a new era of time-resolved structural studies. Here, we review the latest developments in instrumentation, sample delivery, data analysis, crystallization methods, and applications of SFX to important biological questions, and conclude with brief insights into the bright future of structural biology using XFELs. Trends: XFELs allow radiation damage to be overcome, enabling the determination of high-resolution room-temperature structures of difficult-to-crystallize proteins, for which only small crystals are available, and of extremely radiation-sensitive macromolecules, such as metalloenzymes. De novo phasing at XFELs has been established on several different targets and by different methods, thereby enabling the determination of the structure of novel macromolecules of biological interest. The extremely short fs duration of XFEL pulses provides access to dynamic information about unstable intermediate states and irreversible reactions. The development of new injectors, crystal delivery media, and fixed target devices has dramatically reduced the amount of required crystallized protein. Mixing injectors provide an important avenue to study biological interactions in 4D space. Developments in data-processing software have reduced the required amount of data and improved data quality.