The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
TY - UNPB AU - Tono, K. ED - Bishofberger, Kip:Carlsten, Bruce (LANL, Los Alamos, NM, USA)[ORCID:0000-0001-5619-907X] ED - Schaa, Volker RW TI - Observations of Fast Structural Changes with an X-ray FEL: Dynamics Studies on Photoactivated Proteins at SACLA J2 - Proc. of FEL2017, Santa Fe, NM, USA, August 20-25, 2017 C1 - Santa Fe, NM, USA T2 - International Free Electron Laser Conference T3 - 38 LA - english AB - X-ray FELs (XFELs) paved the way for exploring ultrafast structural dynamics in a biological macromolecule. Time-resolved protein crystallography with an XFEL now can reach a resolution of the order of femtosecond. One of the most promising techniques for time-resolved measurement is serial femtosecond crystallography (SFX). We have developed an experimental system for time-resolved SFX at SACLA*. This system has been applied for visualizing structural changes in a photoactivated macromolecule such as bacteriorhodopsin (bR)** or photosystem II (PSII)***. In the application to bR, diffraction measurements cover a wide range of timescales from nanoseconds to milliseconds to fully access the structural transitions in the photocycle. The structural data at more than ten time points provided a cascade of structural changes after photoactivation of the retinal chromophore. This 'movie' clearly shows how bR transports protons through a cell membrane against a chemical-potential gradient. This paper gives an overview of the experimental instruments and techniques for studying ultrafast protein dynamics with XFEL, and recent applications at SACLA. PB - JACoW CP - Geneva, Switzerland ER -