Resolution extension by image summing in serial femtosecond crystallography of two-dimensional membrane-protein crystals Academic Article uri icon


  • 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.


  • Casadei, Cecilia M
  • Tsai, Ching-Ju
  • Barty, Anton
  • Hunter, Mark S
  • Zatsepin, Nadia A
  • Padeste, Celestino
  • Capitani, Guido
  • Benner, W Henry
  • Boutet, Sébastien
  • Hau-Riege, Stefan P
  • Kupitz, Christopher
  • Messerschmidt, Marc
  • Ogren, John I
  • Pardini, Tom
  • Rothschild, Kenneth J
  • Sala, Leonardo
  • Segelke, Brent
  • Williams, Garth J
  • Evans, James E
  • Li, Xiao-Dan
  • Coleman, Matthew
  • Pedrini, Bill
  • Frank, Matthias

publication date

  • 2018

published in