Chemical shift perturbation analysis reveals the substrate binding pocket on TbPin1.

<p>(A) Overlay of the ¹H-¹⁵N HSQC spectra of TbPin1 free (red) and in complex with the unlabeled phosphorylated peptide substrate (blue). The molar ratio of TbPin1 to the phosphorylated peptide is 1∶8. (B) Diagram of amide chemical shift changes (Δδ_HN) of TbPin1 versus residue number at a molar ratio of 1∶8. The average amide chemical shift change () and the mean standard deviation () are indicated with solid and dashed lines, respectively. Residues with chemical shift changes larger than (dashed line) are considered to be involved in substantial contact with the substrate. (C) Mapping the substantial contact residues on the tertiary structure of TbPin1. Residues with significant chemical shift change are highlighted in stick style.