FIGURE 5.

The HIP/PAP N terminus is flexible. A, ribbon diagram of the pro-HIP/PAP crystal structure (RCSB accession: 1UV0) (15). The disordered N-terminal 10 amino acids are indicated by a dotted line, and the locations of the N-terminal disulfide bond (red) and the trypsin cleavage site are indicated. B, experimental ¹⁵NR₁ and R₂ relaxation rates were determined for pro-HIP/PAP, and a plot of the R₁/R₂ ratio is shown. The location of the Arg³⁷–Ile³⁸ trypsin site is indicated by a dashed red line.