Two series of complete and highly redundant data sets were collected at
wavelengths of 1.00 and 2.00 Angstroms on a cadmium derivative of porcine
pancreatic elastase (PPE). Radiation damage to the sample was evaluated
qualitatively by inspecting consecutive difference electron density maps during
the course of the experiment. The nature of the radiation damage was found to be
identical at both wavelengths and was localized primarily at the four disulfide
bridges of PPE, the cadmium site and the two methionine residues. For a
quantitative examination of the radiation damage, the decrease in the peak
height of the cadmium ion in various electron density maps was exploited. Again,
no significant difference in radiation damage between the two wavelengths was
observed. This can be rationalized by considering the wavelength dependencies of
the number of diffracted photons versus the number of absorbed photons and the
energy deposited in the crystal by the latter.
