FIGURE 4.

Irregular polymer formation by ParF-AMPPCP dimer-of-dimer units. A, ribbon diagram of a ParF-AMPPCP filament produced by packing in two different crystal forms. The AMPPCP molecules are shown in Corey-Pauling-Koltun representation. B, schematic diagram highlighting the geometric complementary between dimer-of-dimer units that allows them to interact to generate a long irregular polymer. C, electrostatic surface representation of A, where blue and red represent positive and negative surfaces, respectively. Shown to the right are two subunits rotated 90° to show the electrostatic complementarity of the interacting surfaces. D, mapping of interface residues that were mutated to assay effects on polymer formation.