FIGURE 3.

Identification of p62 UBA dimerization interface and ubiquitin-binding site. A, overlay of ¹H-¹⁵N HSQC spectra of ¹⁵N-labeled p62 UBA at low concentration (10 μm) in the absence and presence of different concentrations of ubiquitin. Peaks observed in the ¹H-¹⁵N HSQC spectrum with a 200 μm sample are masked in black. B, normalized chemical shift changes of backbone amide groups are plotted in a function of amino acid residues. The secondary structures are shown schematically on the top. The position of the MGF motif and the di-leucine motif is also indicated. Normalized chemical shift changes are calculated by (δ_H² + (δ_N/5)²)^1/2, where δ_H and δ_N represent the chemical shift differences in the ¹H and ¹⁵N dimensions.