FIGURE 10.

Comparisons of the catalytic regions and surface charge distributions of ExoU proteins. A, comparison of the catalytic patatin PLA₂ domain of ExoU_{P. flu} (red, chain A used) and ExoU_{P. aer} (silver). The glycine-rich oxyanion hole region (Gly-61–63 in ExoU_{P. flu} and Gly-111–113 in ExoU_{P. aer}), catalytic serine residue (Ser-92 in ExoU_{P. flu} and Ser-142 in ExoU_{P. aer}), and an additional conserved glycine residue important in activity (Gly-235 in ExoU_{P. flu} and Gly-286 in ExoU_{P. aer}) are highlighted. B, charged surface and ribbon representations of the domain four portions of ExoU_{P. flu} and ExoU_{P. aer} and the corresponding portions of the PMT and C. difficile toxin B (TcdB). Dashed yellow line indicates a potential PI(4,5)P₂-binding/recognition site.