FIGURE 3.

(A) Sequence-corrected secondary chemical shift for H^α (Δδ(H^α)) in SUMO-1 at 8 M urea at pH 5.6 and 27°C. The sequence-corrected random coil values used are those determined by Schwarzinger et al. (70). The native secondary structural elements are shown on the top of the figure and the segments showing structural propensities are indicated by solid bars. (B) Selected region from a high resolution (¹H-¹⁵N) HSQC spectrum of SUMO-1 in 8 M urea at pH 5.6 and 27°C. The splitting in the peaks was used to measure ³J (H^N-H^α) coupling constants. (C) Secondary coupling constants (see text) are plotted against sequence for SUMO-1. (D) Far-UV CD spectra of SUMO-1 at pH 5.6 and 27°C, in the absence of urea (shaded circles), and in 8 M urea (open circles).