1. NSLS-II Seminar

    "Plans for In Situ and Submicron Macromolecular Crystallography Beamlines at Diamond Light Source"

    Presented by Gwyndaf Evans and Thomas Sorensen, Diamond LIght Source, United Kingdom

    Monday, May 13, 2013, 2:30 pm
    Bldg 703, large conference room

    Hosted by: Bob Sweet

    Macromolecular crystallisation is often a long and iterative process where initial promising conditions are optimised until crystals suitable for the diffraction experiments are obtained. Crystallisation is in most cases separated from the diffraction experiment, and crystals are more often than not optimised on the basis of their appearance, due to the difficulty in cryocooling and shipping every potential sample to the synchrotron. The objective for a new in situ beamline is to include and develop in situ analysis (diffraction with the crystal still in the crystallization chamber) seamlessly within existing crystallisation pipelines and provide an entirely automated facility for the characterisation of crystallization experiments, and data collection directly from crystals, in situ. High photon flux will enable fast data collection and the possibility to outrun radiation damage. Higher flux can be achieved by using multilayer optics which would deliver a broader bandpass beam. Such a beam would in addition simplify the screening mode as still images would contain relatively more diffraction spots, reducing the need for oscillation images. Beamlines with beams of between 5 and 20 mmicrons in size, and photon fluxes exceeding, 10^12 ph/s, are now available at most 3rd generation synchrotron sources. Their impact has been profound since they have enabled high quality data to be measured from small, poorly ordered, inhomogeneous and weakly diffracting crystals of membrane proteins, large macromolecular complexes and viruses. It has been demonstrated that datasets can be measured and compiled from crystals as small as 1.3 microns in non-optimal conditions using a 5 x 5 micron beam at Diamond beamline I24. Combined with the demonstration that X-ray free electron lasers can yield diffraction data from crystals <500 nm in size there is great potential for the use of submicron beams at synchrotrons with