Macromolecular crystallography using synchrotron radiation

The advantages of using synchrotron x-radiation sources for macromolecular crystallography are reviewed in the light of tabulated structural results from various research centres, notably Orsay and Hamburg. Storage ring sources have the intensity and collimation required for studies of large unit cell crystals and for small crystals. Such intensity may be useful to extend the resolution of the diffraction data or study rapidly decaying crystals. There is the hope of enhancing anomalous dispersion effects, using the tunability of the source, to solve the 'phase problem'. With highly monochromatic and tightly focussed beams there is the possibility of increasing the signal-to-noise ratios and the overall quality of the data. Also, the pulsed nature of the source allows for time resolved measurements on the microsecond or even nanosecond timescale. (U.K.)