Figure 7. The effect of FzlA on FtsZ polymerization is nucleotide dependent.
A) Coomassie-stained SDS PAGE of pellet fractions after high-speed centrifugation of FtsZ polymerization reactions containing 2 μM FtsZ, ± 4 μM FzlA and 0.2 mM of the indicated nucleotide. B) Right angle light scattering of FtsZ polymerization reactions ± 4 μM FzlA and the indicated nucleotides (GTP and GDP were used at 2 mM and GMP-CPP was used at 0.2 mM). C) Negative stain EM of FtsZ polymerization reactions containing 2 μM FtsZ, ± 4 μM FzlA and 0.2 mM of the indicated nucleotide. Mean diameter ± standard deviation is indicated for each. Scale bars = 50 nm. See also Fig. S5. D) Speculative model for formation of FzlA-FtsZ helical bundles in the presence of GTP. FzlA binds to monomers or short oligomers of FtsZ and promotes elongation of paired, curved FtsZ protofilaments with the indicated dimensions.
