title: Identification of patterns in diffraction intensities affected by radiation exposure.
abstract: In an X-ray diffraction experiment, the structure of molecules and the crystal lattice changes owing to chemical reactions and physical processes induced by the absorption of X-ray photons. These structural changes alter structure factors, affecting the scaling and merging of data collected at different absorbed doses. Many crystallographic procedures rely on the analysis of consistency between symmetry-equivalent reflections, so failure to account for the drift of their intensities hinders the structure solution and the interpretation of structural results. The building of a conceptual model of radiation-induced changes in macromolecular crystals is the first step in the process of correcting for radiation-induced inconsistencies in diffraction data. Here the complexity of radiation-induced changes in real and reciprocal space is analysed using matrix singular value decomposition applied to multiple complete datasets obtained from single crystals. The model consists of a resolution-dependent decay correction and a uniform-per-unique-reflection term modelling specific radiation-induced changes. This model is typically sufficient to explain radiation-induced effects observed in diffraction intensities. This analysis will guide the parameterization of the model, enabling its use in subsequent crystallographic calculations.
authors.affiliation: Department of Biophysics, UT Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390, USA.
authors.forename: Dominika
authors.initials: D
authors.lastname: Borek
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Dauter
authors.forename: Zbyszek
authors.initials: Z
authors.lastname: Otwinowski
mesh_terms: D046911:Macromolecular Substances / Q000737:chemistry / Q000528:radiation effects*; D008962:Models, Theoretical; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000528:radiation effects*; D014961:X-Ray Diffraction / Q000379:methods*; D014965:X-Rays
chemical_list: D046911:Macromolecular Substances; D011506:Proteins