Fig. 2: Gradient in ps-ns dynamics across NaK SF.

a Backbone amide ¹⁵N R₁ and {¹H}–¹⁵N NOE values recorded at 750 MHz for NaK in 100 mM K⁺ (black) and 600 mM Na⁺ (red). Secondary structure elements are shown above, where helices are rectangles and loops are lines. The boundaries between elements are based on the 3E8H [10.2210/pdb3E8H/pdb] crystal structure. Residues 63–70 are indicated by the blue lines and are shown as sticks in (b). Error bars were calculated as the SD of 500 Monte Carlo simulations, as described in the Methods. Note that the error in R₁ is smaller than the marker for the majority of residues. b Relaxation data plotted on the NaK SF (showing 2 of 4 opposing subunits). Backbone N atoms are shown as spheres and are colored according to the scale indicated for each parameter. Residues for which data are unavailable due to resonance overlap or lack of assignment are colored black.