Weiss Manfred S, Panjikar Santosh, Mueller-Dieckmann Christoph, Tucker Paul A
EMBL Hamburg Outstation, Germany.
J Synchrotron Radiat. 2005 May;12(Pt 3):304-9. doi: 10.1107/S0909049505003328. Epub 2005 Apr 14.
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.
在猪胰弹性蛋白酶（PPE）的镉衍生物上，于1.00埃和2.00埃波长处收集了两组完整且高度冗余的数据集。在实验过程中，通过检查连续的差分电子密度图对样品的辐射损伤进行了定性评估。发现两个波长下辐射损伤的性质相同，主要定位于PPE的四个二硫键、镉位点和两个甲硫氨酸残基。为了对辐射损伤进行定量检查，利用了各种电子密度图中镉离子峰高的降低。同样，未观察到两个波长之间在辐射损伤方面有显著差异。通过考虑衍射光子数与吸收光子数的波长依赖性以及后者在晶体中沉积的能量，可以对此进行合理的解释。
