Fig. 2.

Pairwise positional symmetric uncertainty in CTX-M9:cefotaxime complexes. Symmetric uncertainty (normalized mutual information) is used to quantify the degree to which atom motions are associated. Rendered in panel (A) are the top 0.25% of symmetric uncertainty pairs shown as brown lines on the CTX-M9:cefotaxime structure. Panel (B) shows a contour plot of the atom–atom symmetric uncertainty matrix contoured at 0.1% intervals from the 99.5th to 100th percentiles. While numerous connections are identified between secondary structural elements, the drug has few high-ranking interactions with protein atoms, indicating a relative isolation of drug motion from protein motion. This is illustrated in the inset rendering in panel (C) and the portion of the symmetric uncertainty matrix corresponding to drug interactions in panel (D) that shows only self-interactions scoring above 99.5% (Color version of this figure is available at Bioinformatics online.)