Figure 4.

Calcium-induced conformational changes in IDPs. DOSY NMR data measuring the decay of the intensities of the methyl regions (centered within 0.85–0.9 ppm) as a function of increasing gradient strength. (A) DOSY NMR data demonstrating that CaCl₂ causes an elongation of aSN_1-140. (B) DOSY NMR data for ANAC046_172-338 in the presence and absence of CaCl₂. ANAC046_172-338 R_h was reduced by ~1.5 Å. (C) A conformational shift was observed in NHE1_680-815, whereby the protein R_h becomes ~8 Å smaller upon calcium binding. (D) Hypothetical conformational changes occurring upon CaCl₂⁺ interaction. DOSY NMR data of DSS1wt (E), DSS1swap (F), DSS1D (G), and DSS1E (H). Arrows indicate increase (up) or decrease (down) in R_h. All proteins were measured at a ratio of 1:250 to CaCl₂.