FIGURE 4.

Mutagenesis of R1 filament forming regions in pSK41 ParM: pSK41 ParM forms filaments different from those of R1 ParM. A, location of the four residues (in blue and labeled) in region Ib of pSK41 ParM that were mutated to test their importance on filament formation. The corresponding residues (location wise) were shown to be essential for filament formation by R1 ParM (14). B, negative stain EM image of wild type pSK41 ParM in the absence of nucleotides. C, negative stain EM image of wild type pSK41 ParM in the presence of 1 mm AMP-PCP, 5 mm MgCl₂. D, negative stain EM image of the quadruple mutant (E37I,N38D,N47T,K48S) pSK41 ParM in the presence of 1 mm AMP-PCP, 5 mm MgCl₂.