Figure 4
Plot of anomalous signal levels at different selenium positions (blue bars) and the levels of specific radiation changes for the same positions (red bars) for Lon protease. The signals are presented in RMS ([sigma]) units of corresponding difference maps. Lon protease has six molecules in the asymmetric unit, so each selenium position in the protomer is represented six times. Additionally, one of the positions has a consistently double conformation in all monomers. The plot clearly shows a different level of order for specific Se positions, which results in a higher anomalous signal for better ordered side chains. The specific radiation changes are also different for different positions, and are not exactly proportional to the anomalous signal levels. The pattern of anomalous signal and specific radiation changes is mostly preserved in equivalent positions of different monomers. However, differences in equivalent positions are larger than expected from random variations (1 RMS level, 1[sigma]), and therefore crystal packing also has some impact on specific changes at Se positions.  [article HTML]

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