06.01.2 Femtosecond Protein Nanocrystallography at the LCLS by tvm12882



Femtosecond Protein Nanocrystallography at the LCLS

John Spence

ASU, Tempe Az, United States

First results will be reported from experiments at the world's first hard X-ray laser (the Linac
Coherent Light Source) at Stanford using membrane protein nanocrystals. X-ray pulses at 2
kV of femtosecond duration were used to read out 30 diffraction patterns per second from a
liquid jet of protein nanocrystals sprayed across the beam. We have evaluated the idea that a
sufficiently short pulse will terminate before radiation damage begins, yet contain sufficient
photons to produce a useful diffraction pattern. Details of the protein-beam injector, which
must provide full hydration, will be given, and the method of data analysis discussed. This
involves merging diffraction data from millions of patterns from sub-micron nanocrystals of
photosystem one , of varying size and in random orientations. Many terrabytes of data were
collected over several days. Plans for pump-probe experiments will also be outlined. This
approach allows structure analysis of proteins which do not produce large crystals, possibly
without radiation damage, directly from solution and without need for cooling. This project is a
large international collaboration, involving the CAMP group from three Max Plank Institutes
and ASU physics. PIs include H. Chapman, P. Fromme, I. Schlichting, B. Doak, U. Weierstall,
J. Uhlich, A. Barty, L. Struder, D. Rolles, the LCLS staff and the ASG team.

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