![FIGURE 3.](F3.medium.gif)
Chemical shift perturbations as a consequence of Cys85 S-nitrosylation. The combined chemical shifts differences (Δδtot) between apo-S100A1 and apo-S100A1-NO variants were calculated as Δδtot = ((ΔδHN)2 + (0.154·ΔδN)2 + (0.341·ΔδCO)2 + (0.276·ΔδCα)2)½ (52). The position of S-nitrosylation is marked with an arrow. Black bars correspond to residues with Δδtot values higher than 0.1 ppm.