Extended Data Fig. 4: NMR experiments of [Rb:E1A] complexes.
From: Conformational buffering underlies functional selection in intrinsically disordered protein regions
a, Central region of 1H-15N TROSY spectra of free 15N-labeled E1A (black) and a 1:1 molar ratio complex of 15N-labeled E1A and unlabeled Rb (red) at 525 μM, with assigned peaks of the free form indicated. The full spectrum of this complex is shown in Fig. 2a. b, Left panel: Overlay of the 1H-15N TROSY spectra of free 15N-labeled E1AΔL (black) and a 1:1 molar ratio complex of 15N -labeled E1AΔL and unlabeled Rb (red) at 315 μM. Right panel: central region of the spectra with assigned peaks of the free form indicated c, Left panel: Overlay of the 1H-15N TROSY spectra of free 15N-labeled E1AΔE (black) and a 1:1 molar ratio complex of 15N-labeled E1AΔE and unlabeled Rb (red) at 315 μM. Right panel: central region of the spectra with assigned peaks of the free form indicated. The low chemical shift dispersions in the 1H dimension for E1AΔL and E1AΔE denote their disordered nature, like that seen in E1A. There is no change in peak dispersion upon binding with Rb, indicating that linker regions of the E1AΔL and E1AΔE mutants remain largely disordered in the [E1AΔL:Rb] and [E1AΔE:Rb] complexes. d, Plot of chemical shift changes upon binding as a function of residue number for E1AWT, E1AΔL and E1AΔE. Dashed line at 0.2 ppm corresponds to the digital resolution of the experiment. The small chemical shift changes for almost all of the linker residues suggest very little if no interaction with Rb. I/I0 ratio is overlaid for comparison (colored lines). Dots on the bottom correspond to the residues of each variant whose 1H-15N intensities in the bound state is = 0, so the chemical shift changes could not be measured.
