Premium
X‐ray absorption by macromolecular crystals: the effects of wavelength and crystal composition on absorbed dose
Author(s) -
Murray James W.,
Garman Elspeth F.,
Ravelli Raimond B. G.
Publication year - 2004
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889804010660
Subject(s) - absorption (acoustics) , absorbed dose , diffraction , crystal (programming language) , synchrotron radiation , synchrotron , photon , radiation , optics , materials science , beam (structure) , computational physics , physics , computer science , programming language
Radiation damage restricts the useful lifetime for macromolecular crystals in the X‐ray beam, even at cryotemperatures. With the development of structural genomics pipelines, it will be essential to incorporate projected crystal lifetime information into the automated data collection software routines. As a first step towards this goal, a computer program, RADDOSE , is presented which is designed for use by crystallographers in optimizing the amount of data that can be obtained from a particular cryo‐cooled crystal at synchrotron beamlines. The program uses the composition of the crystal and buffer constituents, as well as the beam energy, flux and dimensions, to compute the absorption coefficients and hence the theoretical time taken to reach an absorbed dose of 2 × Gy, the so‐called `Henderson limit'. At this dose, the intensity of the diffraction pattern is predicted to be halved. A `diffraction–dose efficiency' quantity is introduced, for the convenient comparison of absorbed dose per diffracted photon for different crystals. Four example cases are considered, and the implications for anomalous data collection are discussed in the light of the results from RADDOSE .