Figure 3

Interaction of MapZ_cyto with monomeric FtsZ. (a) Superimposition of the ¹H–¹⁵N BEST-TROSY correlation spectra recorded on MapZ_cyto in absence (blue) and in presence (red) of 4.7 molar equivalent of FtsZ_a. The samples were prepared with 88 µM final concentration of ¹⁵N MapZ_cyto in 30 mM HEPES, 50 mM KCl buffer at pH 7.5. NMR experiments were recorded on 16.5-T Bruker Avance III spectrometer at 5 °C. (b) Peak intensity decrease upon addition of 4.7 molar equivalent of FtsZ_a on MapZ_cyto are reported as a function of the residue position in MapZ primary sequence. For each assigned resonance that is not significantly overlapped, the intensities I₀ and I₁ are measured in the reference blue spectrum containing only MapZ_cyto and in the red spectrum containing the MapZ_cyto-FtsZ_a mixture, respectively, reported in (a). The peak intensity decrease (in %) is calculated as the \(\frac{{{\rm{I}}}_{0}-{{\rm{I}}}_{1}}{{{\rm{I}}}_{0}}\) ratio. (c) A 3D plot reporting the peak intensity decrease as a function of the residue position in MapZ primary sequence along MapZ_cyto titration by polymeric FtsZ_b (FtsZ_b). Blue, red, green and yellow histograms represent 1:1, 1:3, 1:4 and 1:6 molar ratios of MapZ_cyto:FtsZ_pol. Samples were prepared from 0.5 mM and 210 µM stock solutions of MapZ_cyto and FtsZ_b, respectively, in 30 mM HEPES, 200 mM KCl buffer at pH 7.5. The final MapZ_cyto concentration in each sample was 30 µM, and 10 mM GTP and MgCl₂ were added to polymerize FtsZ, as verified by electron microscopy.