Fig. 6.

Structural changes upon ligand binding. (a) Overlay of the hSPSB2/VASA complex and apo-mSPSB2 structure.¹⁴ Side-chain rearrangements between the ligand-free and ligand-bound state are largely limited to hSPSB2 Trp207. The hSPSB2-bound VASA peptide is shown in ribbon representation for reference and colored orange. (b) Overlay of the ligand-free structures of hSPSB4 and mSPSB2 reveals more substantial structural changes in loops B, C, and E. The side chain of hSPSB4 Trp217 also shows a substantial rotamer change from mSPSB2 Trp207. Note that this residue has an unusual backbone amide chemical shift in apo-mSPSB2.⁵