FIGURE 3.

Sequence alignment of Psu with its homologues. Important conserved residues are represented with color codes similar to those used in Fig. 1a. Secondary structural elements are overlaid on top and numbered. Yellow, coiled coil; pink, dimerization region; green, C-terminal belt; red, residues passing through the hole in the dimerization region. The yellow circle with the helix within represents the helix that passes through the knotted interface. E9XHX9, Escherichia coli TW10509; E0T1Q3, Edwardsiella tarda (strain FL6–60); E0T1Q3, Enterobacter sp. (strain 638); A4WDI7, Salmonella paratyphi B (strain ATCC BAA-1250/SPB7); A9MZ75, Salmonella arizonae (strain ATCC BAA-731/CDC346–86/RSK2980); D0ZF48, Edwardsiella tarda (strain EIB202).