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Title: Towards phasing using high X-ray intensity

X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential `bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. In conclusion, a pattern sorting scheme is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5] ;  [6] ;  [7] ;  [5] ;  [8] ;  [5] ;  [5] ;  [9] ;  [10] ;  [5] ;  [11]
  1. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Univ. of Hamburg, Hamburg (Germany)
  2. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Hamburg (Germany)
  3. MPI for Medical Research, Heidelberg (Germany)
  4. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
  5. Max Planck Inst. for Medical Research, Heidelberg (Germany)
  6. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  7. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Uppsala Univ., Uppsala (Sweden)
  8. European Molecular Biology Lab. (EMBL), Grenoble (France)
  9. Uppsala Univ., Uppsala (Sweden)
  10. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Hamburg (Germany); Univ. of Hamburg, Hamburg (Germany)
  11. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Univ. of Hamburg, Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Hamburg (Germany)
Publication Date:
OSTI Identifier:
1228035
Grant/Contract Number:
AC03-76SF00515
Type:
Accepted Manuscript
Journal Name:
IUCrJ
Additional Journal Information:
Journal Volume: 2; Journal Issue: 6; Journal ID: ISSN 2052-2525
Publisher:
International Union of Crystallography
Research Org:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS serial femtosecond crystallography; high-intensity phasing; radiation damage; electronic damage; X-ray free-electron lasers; high XFEL doses