Simultaneous Femtosecond X-ray Spectroscopy and Diffraction of Photosystem II at Room Temperature

One Protein, Two Probes A central challenge in the use of x-ray diffraction to characterize macromolecular structure is the propensity of the high-energy radiation to damage the sample during data collection. Recently, a powerful accelerator-based, ultrafast x-ray laser source has been used to determine the geometric structures of small protein crystals too fragile for conventional diffraction techniques. Kern et al. (p. 491 , published online...