Fig. 3: Ub 11AcK and Ub 11Q are structurally different.

a Superimposition of the two-dimensional heteronuclear ¹H–¹⁵N HSQC NMR spectra of Ub 11AcK (red), Ub 11Q (blue) and nonmodified Ub (wt, gray), each with the respective side chain indicated. The labeling of the backbone amide resonances by the one letter code corresponds to the spectrum of Ub 11AcK. b–e Weighted chemical shift perturbation (CSP, Δω) mappings are shown for Ub 11AcK (b), Ub 11Q (c), Ub 11A (d), and Ub 11R (e) versus nonmodified Ub (wt). The cutoff values are the same for all plots and were calculated by taking the mean (horizontal solid line) and the mean plus one standard deviation (horizontal dashed line), respectively, over all Δω values from (b) to (e) excluding values from the respective residue at position 11. Secondary structural elements according to the NMR solution structure of nonmodified Ub (PDB ID 1D3Z)⁷⁹ are schematically depicted on top of all graphs. The same structure is used in the lower panel to illustrate the location and amplitude of the perturbations with colors from white to red in continuous mode. The side chain of K11 is drawn as stick model in gray in the structure and the position in the sequence is indicated by an arrow on top of the graphs. Source data are provided as a Source Data file.