Matching Items (113)
Description
X-ray free-electron lasers (XFELs) provide new opportunities for structure determination of biomolecules, viruses and nanomaterials. With unprecedented peak brilliance and ultra-short pulse duration, XFELs can tolerate higher X-ray doses by exploiting the femtosecond-scale exposure time, and can thus go beyond the resolution limits achieved with conventional X-ray diffraction imaging techniques. Using XFELs, it is possible to collect scattering information from single particles at high resolution, however particle heterogeneity and unknown orientations complicate data merging in three-dimensional space. Using the Linac Coherent Light Source (LCLS), synthetic inorganic nanocrystals with a core–shell architecture were used as a model system for proof-of-principle coherent diffractive single-particle imaging experiments. To deal with the heterogeneity of the core–shell particles, new computational methods have been developed to extract the particle size and orientation from the scattering data to assist data merging. The size distribution agrees with that obtained by electron microscopy and the merged data support a model with a core–shell architecture.
ContributorsLi, Xuanxuan (Author) / Spence, John (Author) / Hogue, Brenda (Author) / Liu, Haiguang (Author) / College of Liberal Arts and Sciences (Contributor) / Department of Physics (Contributor) / Biodesign Institute (Contributor) / Applied Structural Discovery (Contributor)
Created2017-08-27
Description
The invention of the laser in the 1950 s for visible light and microwaves, and the slow but steady recognition of its manifold uses, is a truly remarkable story in the history of science. But the severe λ[superscript 3] dependence of the ratio of stimulated (mostly coherent) to spontaneous (incoherent) emission meant that efforts to build an X-ray laser seemed hopeless for decades. As so often happens in the history of science, the breakthrough eventually occurred at the interface of several fields – synchrotron science (and especially their insertion devices), laser physics, and work on microwave tubes for radar, emerging from the second world war. Synchrotrons themselves were an outgrowth of the particle accelerators of nuclear physics, whose X-ray radiation was considered a nuisance. All of this culminated recently in the construction of the first hard-X-ray laser, the US Department of Energy's Linac Coherent Light Source (LCLS), at their SLAC laboratory near Stanford. The first X-ray lasing occurred in that two-mile long tunnel on April 21, 2009, at about 2 kV, in an all-or-nothing moment of intense excitement, as theoretical predictions proved spot-on. The new laser principle needed for hard-X-ray lasing, the free-electron laser (FEL), was first demonstrated in the infra-red region at Stanford in 1975 in John Madey's group, following earlier theoretical work by Motz and Phillips on microwave tubes. Other FELs soon followed, in the microwave and visible region, leading to the LCLS. The XFEL method provides brief pulses of X-ray laser radiation by the SASE (self-amplified spontaneous emission) process, using a resonant undulator driven by a LINAC electron accelerator. Each LCLS pulse, of 10 fs duration (repeated 120 times a second) contains about 10[superscript 12] hard-X-ray photons, about the same number that a synchrotron might generate in a second.
ContributorsSpence, John (Author) / College of Liberal Arts and Sciences (Contributor) / Department of Physics (Contributor)
Created2014-04-30
Description
X-ray diffraction patterns from two-dimensional (2-D) protein crystals obtained using femtosecond X-ray pulses from an X-ray free-electron laser (XFEL) are presented. To date, it has not been possible to acquire transmission X-ray diffraction patterns from individual 2-D protein crystals due to radiation damage. However, the intense and ultrafast pulses generated by an XFEL permit a new method of collecting diffraction data before the sample is destroyed. Utilizing a diffract-before-destroy approach at the Linac Coherent Light Source, Bragg diffraction was acquired to better than 8.5 Å resolution for two different 2-D protein crystal samples each less than 10 nm thick and maintained at room temperature. These proof-of-principle results show promise for structural analysis of both soluble and membrane proteins arranged as 2-D crystals without requiring cryogenic conditions or the formation of three-dimensional crystals.
ContributorsFrank, Matthias (Author) / Carlson, David B. (Author) / Hunter, Mark S. (Author) / Williams, Garth J. (Author) / Messerschmidt, Marc (Author) / Zatsepin, Nadia (Author) / Barty, Anton (Author) / Benner, W. Henry (Author) / Chu, Kaiqin (Author) / Graf, Alexander T. (Author) / Hau-Riege, Stefan P. (Author) / Kirian, Richard A. (Author) / Padeste, Celestino (Author) / Pardini, Tommaso (Author) / Pedrini, Bill (Author) / Segelke, Brent (Author) / Seibert, M. Marvin (Author) / Spence, John (Author) / Tsai, Ching-Ju (Author) / Lane, Stephen M. (Author) / Li, Xiao-Dan (Author) / Schertler, Gebhard (Author) / Boutet, Sebastien (Author) / Coleman, Matthew (Author) / Evans, James E. (Author) / College of Liberal Arts and Sciences (Contributor) / Department of Physics (Contributor)
Created2014-02-28
ContributorsBeaudoin, M. (Author) / Johnson, Shane R. (Author) / Boonzaayer, Martin D. (Author) / Zhang, Yong-Hang (Author) / Johs, B. (Author)
Created1999
ContributorsJohnson, Shane R. (Author) / Grassi, E. (Author) / Beaudoin, M. (Author) / Boonzaayer, Martin D. (Author) / Tsakalis, K. S. (Author) / Zhang, Yong-Hang (Author)
Created1999
ContributorsBraun, W. (Author) / Möller, H. (Author) / Johnson, Shane R. (Author) / Zhang, Yong-Hang (Author)
Created1999
ContributorsDowd, P. (Author) / Braun, W. (Author) / Smith, David J. (Author) / Ryu, C. M. (Author) / Guo, C.-Z. (Author) / Chen, S.-L. (Author) / Koelle, U. (Author) / Johnson, Shane R. (Author) / Zhang, Yong-Hang (Author)
Created1999
ContributorsJohnson, Shane R. (Author) / Dowd, P. (Author) / Braun, W. (Author) / Koelle, U. (Author) / Ryu, C. M. (Author) / Beaudoin, M. (Author) / Guo, C.-Z. (Author) / Zhang, Yong-Hang (Author)
Created2000
ContributorsBeaudoin, M. (Author) / Grassi, E. (Author) / Johnson, Shane R. (Author) / Ramaswamy, K. (Author) / Tsakalis, K. (Author) / Alford, T. L. (Author) / Zhang, Yong-Hang (Author)
Created2000
ContributorsBraun, W. (Author) / Dowd, P. (Author) / Guo, C.-Z. (Author) / Chen, S.-L. (Author) / Ryu, C. M. (Author) / Koelle, U. (Author) / Johnson, Shane R. (Author) / Zhang, Yong-Hang (Author) / Tomm, J. W. (Author) / Elsässer, T. (Author) / Smith, D. J. (Author)
Created2000