Fig. 4.

NMR map of the residues of RKIP^WT and P74L mutant involved in PKA-C/RKIP interaction interface. (A and B) [¹H,¹⁵N]-HSQC spectra showing the backbone chemical shift changes of selected resonances of (A) RKIP^WT and (B) RKIP^P74L upon titration of increasing amount of PKA-C/ATPγN complex. (C) CSP of the amide fingerprint of RKIP^WT and RKIP^P74L mutant alone (Δδ_free) and in a 1:2 complex with PKA-C/ATPγN (Δδ_bound) vs. residues, calculated using Eq. 1. The residues that show a CSP value two times greater than 1 SD from the average CSP (gray dashed line) are indicated in the histogram. (D–G) Cartoon (D) and surface (E) mapping of the amide CSP of RKIP^WT or cartoon (F) and surface (G) of P74L mutant onto the three-dimensional structure (Protein Data Bank [PDB] ID 2IQY). The cartoons and the surfaces are colored according the CSP values ranging from 0.015 to 0.15 ppm.