[What Kind of Measurements Can Be Made with an X-ray Free Electron Laser at SACLA?].

Three-dimensional structural information is indispensable to understand the function of proteins in living organisms and X-ray crystallography plays a major role in determining the three-dimensional structure. X-ray free-electron laser (XFEL), which is intense and femtosecond X-ray pulses, enables us to obtain X-ray diffraction intensity data before the destruction of protein molecules, and is expected to be a technology to obtain dynamic structural information. This year marks the 10th anniversary of SPring-8 Angstrom Compact Free Electron Laser (SACLA), Japan's X-ray free electron laser facility. In this review, I describe the damage-free crystal structure analysis, de novo crystal structure determination using single wavelength anomalous dispersion by serial femtosecond crystallography (SFX), and time-resolved X-ray crystallography that have been performed at SACLA.