NMR characterization of Ixolaris-FX complex using ¹⁵N probes. (A) Overlays of representative regions from 2-dimensional ¹⁵N,¹H HSQC spectra recorded in the free (magenta) and 0.5:1 FX-bound (black) state of the Ixolaris. (B) Histogram of CSPs and (C) peak intensity ratio (I_bound/I_free) as a function of Ixolaris residue number. The dashed line indicates the magnitude of the CSPs corresponding to the 2 standard deviation greater than the mean. (D) Mapping of amides probes on the NMR structure of Ixolaris with K1 domain colored wheat and K2 domain colored light blue. Two types of observed changes are highlighted with different colors: residues with significant chemical shift changes are in magenta spheres (>2 standard deviation from the average), whereas residues with significantly attenuated intensity resonances (>1 standard deviation from the average) in the bound form are shown in cyan spheres.