Figure 5.

Average distances (Å) between backbone amide nitrogen and oxygen atoms of the residues in the EF hands forming the β-sheets in the apo case (blue), holo case (red), and half-saturated case (green). Standard deviations are shown. The yellow line indicates the 3.5 Å mark, which we define as the hydrogen-bond cutoff. Ca²⁺ ion binding disrupts the β-sheet hydrogen-bond network in both the half-saturated and holo states. To see this figure in color, go online.