Mapping the Ship2-Sam binding interface for Arap3-Sam. A. Overlay of [1H, 15N]-HSQC spectra of 15N labeled Ship2-Sam (200 μM) in absence (magenta) and presence (cyan) of unlabeled Arap3-Sam (233 μM). B. Graph reporting the normalized chemical shift deviations (Δδ = [(ΔHN)2 + (0.17 * Δ15N)2]1/2) versus the residue number. Residues E26, S30, L45, H47, N48, W50, D51, L53, E54, F55, L56, S57, D58, I59, T60, D63, L64, E66, A67, V69, L82, L84 show normalized deviations with values higher that 0.1 ppm. Residues 29 and 71 have not been reported due to spectral overlaps. C. Amino acids with normalized chemical shifts deviations (Δδ values) greater than 0.1 ppm are colored in cyan on the 3D solution structure of Ship2-Sam (conformer number 1, pdb code: 2K4P) in its ribbon (left panel) and surface (right panel) representations. The peptide region corresponding to the Shiptide is underlined in the left panel. D. ITC data showing the Arap3-Sam (75 μM) titration with the Shiptide peptide (1 mM). The solid line in the lower panel represents the fit of the calorimetric data to a single binding site model.
Leone et al. BMC Structural Biology 2009 9:59 doi:10.1186/1472-6807-9-59