Figure 3.

Examples of 2D protein-based NMR assays. Overlays of 2D heteronuclear NMR spectra of the vSrc-SH2 domain collected in the absence (red) and presence (blue) of a ligand. Panels A and B show [¹H, ¹⁵N] SOFAST-HMQC spectra collected for backbone ¹H^N, ¹⁵N (A) or Arg ¹H^ε, ¹⁵N^ε side chains (B). Panel C shows the spectra obtained with a modified [¹H, ¹⁵N] HSQC (heteronuclear single-quantum coherence) experiment that selects for the ¹H^δ, ¹⁵N^δ and ¹H^ε, ¹⁵N^ε side chains of Asn and Gln, respectively. Panel D shows the [¹H, ¹³C] HSQC spectra in the aliphatic region of the protein. Selected chemical shift perturbations in well-resolved regions of each spectrum are highlighted.