On the routine use of soft X-rays in macromolecular crystallography

A diffraction data set has been collected from a blood coagulation factor XIII–Ca²⁺ complex crystal at the X-ray diffraction beamline of the ELETTRA synchrotron (Trieste, Italy) at a wavelength of 2.6 Å. The data collection could be carried out using the beamline as is, without making any time-consuming changes to the apparatus. Various data-processing schemes have been employed and it has been observed that local or detector scaling procedures are essential for producing the `best' anomalous differences.