FIGURE 3.

NMR chemical shift changes of hHR23A(223–363) amide resonances induced by Vpr binding. A, superposition of the 900-MHz ¹H-¹⁵N HSQC spectra of hHR23A(223–363) alone (blue) and the hHR23A(223–363)-Vpr complex (red) at 291 K. Representative hHR23A(223–363) resonances are labeled with residue names and numbers. Note that the hHR23A(223–363)-Vpr complex spectrum (red) also contains Vpr resonances (enclosed by rectangles) because the proteins were coexpressed and, therefore, both labeled with ¹⁵N and ¹³C. B, ¹H,¹⁵N-combined chemical shift differences, plotted along the linear amino acid sequence, calculated using the equation (Δδ_HN² + (0.14*Δδ_N)²)^1/2, with Δδ_HN and Δδ_N representing the ¹HN and ¹⁵N chemical shift differences between resonances of the free and the Vpr-bound hHR23A(223–363).