Resolution Extension by Image Summing in Serial Femtosecond Crystallography of Two-Dimensional Membrane-Protein Crystals
Previous proof-of-concept measurements on single-layer two-dimensional membrane-protein crystals performed at X-ray free-electron lasers (FELs) have demonstrated that the collection of meaningful diffraction patterns, which is not possible at synchrotrons because of radiation-damage issues, is feasible. Here, the results obtained from the analysis of a thousand single-shot, room-temperature X-ray FEL diffraction images from two-dimensional crystals of a bacteriorhodopsin mutant are reported in detail. The high redundancy in the measurements boosts the intensity signal-to-noise ratio, so that the values of the diffracted intensities can be reliably determined down to the detector-edge resolution of 4 Å. The results show that two-dimensional serial crystallography at X-ray FELs is a suitable method to study membrane proteins to near-atomic length scales at ambient temperature. The method presented here can be extended to pump–probe studies of optically triggered structural changes on submillisecond timescales in two-dimensional crystals, which allow functionally relevant large-scale motions that may be quenched in three-dimensional crystals.
- Author (aut): Casadei, Cecilia M.
- Author (aut): Tsai, Ching-Ju
- Author (aut): Barty, Anton
- Author (aut): Hunter, Mark S.
- Author (aut): Zatsepin, Nadia
- Author (aut): Padeste, Celestino
- Author (aut): Capitani, Guido
- Author (aut): Benner, W. Henry
- Author (aut): Boutet, Sebastien
- Author (aut): Hau-Riege, Stefan P.
- Author (aut): Kupitz, Christopher
- Author (aut): Messerschmidt, Marc
- Author (aut): Ogren, John I.
- Author (aut): Pardini, Tom
- Author (aut): Rothschild, Kenneth J.
- Author (aut): Sala, Leonardo
- Author (aut): Segelke, Brent
- Author (aut): Williams, Garth J.
- Author (aut): Evans, James E.
- Author (aut): Li, Xiao-Dan
- Author (aut): Coleman, Matthew
- Author (aut): Pedrini, Bill
- Author (aut): Frank, Matthias
- Contributor (ctb): College of Liberal Arts and Sciences