Fig. 6.
Differential dose-dependent radiation damage. Side-chain densities for selected Glu and Asp residues are shown to illustrate the effects of radiation damage by comparison of maps obtained with progressively higher total electron doses. Density maps were derived by using the first 8, 16, or 24 frames (Top, Middle, and Bottom), corresponding to 10, 20, or 30 e−/Å2 total dose, respectively. In comparison with Arg and Leu side chains (illustrated using Arg-52 and Leu-7 as examples), Glu and Asp side chains (illustrated by using Glu-67, Glu-243, and Asp-96) are much more sensitive to radiation damage showing increased loss of density (26%, 22%, and 10% for Glu-67, Glu-243, and Asp-96, respectively) with an increase in dose from 10 to 30 e−/Å2 (see also Fig. S12 for a quantitative analysis of residue-specific radiation damage at different dose levels).