FIGURE 2.

Comparison of ¹⁵N-¹H HSQC spectra of TuSp NT (blue,A and D) and its potential monomeric mutants TuSp NT_A70E (red,B and E), and TuSp NT_D40RR63D (green,C and F) in 300 mM NaCl, 20 mM NaPi, pH 7.2 and 20 mM NaCl, 20 mM NaOAc, pH 5.5 respectively. (G) Averaged backbone amide ¹⁵N and ¹H chemical shift differences $\Delta {\delta }_{av}=\sqrt{{\left(0.1\Delta {\delta }_N\right)}^2+{\left(\Delta {\delta }_H\right)}^2}$ between TuSp NT_A70E at pH 7.2 and wt TuSp NT dimer at pH 5.5. Residues showing chemical shift differences larger than mean plus one standard deviation are highlighted in yellow and identified. Locations of helices are indicated with a red line.