Figure 4.

Schematic diagram of the chemical shift perturbations of the PR_D25N upon substrate C binding. Vertical lines indicate residues whose amide ¹⁵N and ¹H chemical shifts differ in the two monomer subunits but whose ¹³Cα chemical shifts are indistinguishable. Open rectangles indicate residues in regions (I–IV) whose ¹⁵N, ¹H, and ¹³Cα chemical shifts are differently assigned in each monomer subunit. Black dots indicate residues whose signals are perturbed in the active protease upon addition of substrate C (the residues described in Fig. 1A▶).