Tables for
Volume F
Crystallography of biological macromolecules
Edited by E. Arnold, D. M. Himmel and M. G. Rossmann

International Tables for Crystallography (2012). Vol. F, ch. 8.1, p. 189   | 1 | 2 |

Section 8.1.1. Introduction

J. R. Helliwella*

aDepartment of Chemistry, University of Manchester, M13 9PL, England
Correspondence e-mail:

8.1.1. Introduction

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Synchrotron radiation (SR) has had a profound impact on the field of protein crystallography. The properties of high spectral brightness and tunability have enabled higher-resolution structure determinations, multiple-wavelength anomalous-dispersion (MAD) techniques, studies of much larger molecular weight structures, the use of small crystals and dynamical time-resolved structural studies. The use of SR required development of suitable X-ray beamline optics for focusing and monochromatization of the beam, which had to be stable in position and spectral character, for rotating-crystal data collection. Finely focused polychromatic beams have been used for ultra-fast data collection with the most advanced SR sources, where a single bunch pulse of X-rays can be strong enough to yield Laue diffraction data. The optimal recording of the diffraction patterns has necessitated the development of improved area detectors, along with associated data-acquisition hardware and data-processing algorithms. Sample cooling and freezing have reduced and greatly diminished, although not eliminated, radiation damage, respectively. In turn, even smaller crystals have been used. However, new X-radiation damage challenges are being reached. The low emittance of SR sources, with their small source size and beam divergence, corresponds well with the small size and low mosaicity of protein crystal samples. The evolution of SR source spectral brightness each year over the last twenty years has changed by many orders of magnitude, a remarkable trend in technical capability.

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