Figure 2.

Intermolecular PRE (¹H_N–Γ₂) profiles observed on ¹⁵N-labeled SH3^WTΔ57 (left panels), SH3^WT (middle panels), and SH3^Mut (right panels) in the presence of GroEL paramagnetically labeled with EDTA–Mn²⁺ at six cysteine engineered sites. Regions with ¹H_N-Γ₂ > 5 s⁻¹ are shaded. The secondary structure is shown above the panels. PREs are measured using a ¹H–¹⁵N correlation-based experiment²¹ as the difference in corresponding ¹H_N-R₂ values between paramagnetic and diamagnetic reference samples. Data were recorded at 800 MHz and 10 °C on samples containing 100 μM ¹⁵N-labeled SH3 and 100 μM (in subunits) GroEL. The locations of sites I/I′/I″ (top), II (middle), and III (bottom) on the molecular surface of SH3^WTΔ57 are shown on the right, with residues color coded as in Figure 1. In the views for sites II and III (rotated by 180° relative to the top view), site I is shown in yellow.