issue contents

Journal logoJOURNAL OF
ISSN: 1600-5775

November 2002 issue

Includes papers presented at the Second International Workshop on X-ray Damage to Crystalline Biological Samples

Chicago, USA, December 2001

Highlighted illustration

Cover illustration: Cryocooling a lysozyme crystal in a 100 K gas stream, see Snell, Judge, Larson and van der Woerd, pages 361-367.

facility information

radiation damage workshop

J. Synchrotron Rad. (2002). 9, 327-328
doi: 10.1107/S0909049502014565
link to html
A short summary of the current state of knowledge regarding radiation damage to crystalline biological specimens is provided, taking into account information provided in recently published papers.

J. Synchrotron Rad. (2002). 9, 329-332
doi: 10.1107/S0909049502014553
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The chemical processes possible when protein crystals suffer radiation damage in an X-ray beam are outlined. Approaches to reducing the damage are discussed from a radiation chemistry viewpoint.

J. Synchrotron Rad. (2002). 9, 333-341
doi: 10.1107/S0909049502014528
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X-ray damage to lipidic mesophases is shown to be free-radical mediated, to involve chemical degradation, to trigger phase transitions and to continue post-irradiation. Dose rate, X-ray energy, beam heating and dispersing-medium effects were investigated. X-ray diffraction is not a reliable indication of radiation damage. This work has relevance to physiological processes, such as aging, that involve oxidative damage.

J. Synchrotron Rad. (2002). 9, 342-346
doi: 10.1107/S0909049502014589
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Changes in disulfide bond lengths upon X-ray irradiation are examined. Together with microspetrophotometric data and quantum chemical calculations, they are found to be indicative of the formation of disulfide radicals.

J. Synchrotron Rad. (2002). 9, 347-354
doi: 10.1107/S0909049502014632
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Unit-cell volume expansion is investigated as a radiation-damage metric in cryocooled protein crystals and found not to be a reliable indicator. The radical scavengers styrene and ascorbate are tested as means of reducing X-ray damage at 100K: styrene is found to be ineffective, but ascorbate is a promising candidate.

J. Synchrotron Rad. (2002). 9, 355-360
doi: 10.1107/S0909049502014541
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The unit-cell volume increase upon radiation damage has been used to study the effect of temperature and X-ray dose rate on crystals of holoferritin. A dose-rate effect has been found, and it is postulated that trapped radicals become mobile at ca 180K.

J. Synchrotron Rad. (2002). 9, 361-367
doi: 10.1107/S090904950201453X
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In this work it is shown for the first time that it is possible to thermally image macromolecular crystals cooled in a 100K nitrogen gas stream.

J. Synchrotron Rad. (2002). 9, 368-374
doi: 10.1107/S0909049502014620
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The temperature, radiation energy and flux dependence on the rate of the change in d-spacing were investigated in order to monitor radiation damage in organic small molecules and protein crystals.

J. Synchrotron Rad. (2002). 9, 375-381
doi: 10.1107/S0909049502014577
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Ultrahigh-resolution data collected from D-xylose isomerase crystals suggest that, when cooled with He rather than N2, these crystals maintain order and that high-resolution data are less affected by increased radiation load. An apparent phase transition in macromolecular crystals between 16 and 100K requires investigation to broaden cryogenic He use.

research papers

J. Synchrotron Rad. (2002). 9, 383-393
doi: 10.1107/S0909049502016308
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A linear-transmission Fresnel-zone-plate lens is used for coupling a monochromatic X-ray beam of 13.2keV into a planar X-ray waveguide. The coherent properties of the beam are investigated by comparing the experimental data with numerical calculations in which partial coherence is taken into account by propagation of the mutual intensity function.

J. Synchrotron Rad. (2002). 9, 394-400
doi: 10.1107/S0909049502014000
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The O K-edge spectra of a series of Ti-bearing compounds with Ti in different structural and chemical environments are measured using electron energy-loss specroscopy and are analyzed using ab initio full multiple-scattering calculations.

computer programs

J. Synchrotron Rad. (2002). 9, 401-406
doi: 10.1107/S0909049502015170
link to html
The Blu-Ice and Distributed Control System software packages unify control over hardware at macromolecular crystallography beamlines and provide a platform for increasing beamline ease of use, automation and remote accessibility.
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