Figure 3.

(A) Representative NMR spectral overlays of HisF ¹³CH₃-ILV methyl groups in apo (upper) and PRFAR-bound IGPS (lower) showing temperature-dependent resonance shifts. Resonances in red correspond to spectra collected at 303 K, blue to 323 K, and green to 343 K while arrows indicate the direction of shifts with increasing temperature. Correlations between the temperature dependencies of chemical shifts in ¹H¹³CH₃-ILV spectra of apo and PRFAR-bound IGPS are shown for the carbon (B) and proton (C) dimensions. Temperature-dependent shifts outside of 90% confidence boundaries are mapped onto the HisF structure in (D), where areas in black denote residues with proton shifts outside of these boundaries, red denotes carbon shifts outside of these boundaries, and blue denotes residues with both proton and carbon shifts outside of these boundaries.