NMR analysis of the titration of unlabeled collagen III-30 peptide to ¹⁵N-labeled hLAIR1-CBD. (A) Assigned {¹H;¹⁵N}-HSQC spectrum of the isolated LAIR-1 ectodomain in the absence of ligand. Gray lines connect the resonances of asparagine and glutamine side chain amides. The boxed region contains arginine side chain resonances. Side chain assignments are indicated by sc. Unassigned signals are indicated by #. (B) Selected regions of the overlay of {¹H;¹⁵N}-HSQC spectra recorded at different peptide III-30 concentrations. Shown are representative examples of residues with large chemical shift changes that are in intermediate-to-slow exchange (R59, R62, Y68, I102, S110, #), residues that are in fast-to-intermediate exchange (V74), and residues that show no shift (E24, V120) or shifts smaller than a line-width (E81, A96). The arrows indicate the direction of peak displacement. Color coding reflects the relative peptide concentration as indicated. (C) Mapping of spectral changes on a ribbon representation of hLAIR1-CBD (left), a surface representation in the same orientation (middle), and a surface representation rotated by 180° around a vertical axis (right). White indicates no data due to lacking assignments or spectral overlap; blue, no spectral change or change smaller than one line-width; orange, residues in fast-to-intermediate exchange; and red, residues in intermediate-to-slow exchange. Residues of interest are labeled.