Fig. 4: The design model shows atomic-level agreement with its NMR solution structure.

A Boskar4 solution structure shows an ensemble deviation from the average structure of 0.8, and 2.0 Å from the designed coordinates. The design model (orange) is shown against the NMR ensemble (dark blue). The boxplot shows the median and spread across the ensemble frames. B The backbone atoms RMSD of the binding epitope averaged at 1.0 Å, while all-atom RMSD of averaged at 1.2 Å, highlighting the design precision. The design model residues (yellow) are shown against the NMR ensemble (purple), and the box plot shows the deviations across the ensemble. The boxplot shows the median and spread across the ensemble frames. The box plots represent median (central line), 1st and 3rd interquartile range (box), and minimum and maximum of 1.5 times the latter interquartile range (whiskers). C Residue-wise R-factor values for the covered residues are shown (top), indicating the normalised CNH-NOESY RMSD from the expected spectra by the final ensemble. The fold-factor shown (bottom), a metric which signifies the R-factor reduction by non-local residue-residue contacts, shows the contribution of buried helical residues to Boskar4 folding. D Both amide proton exchange (top) and ¹⁵N{¹H}NOEs (bottom) show the backbone amides of the helical residues to be solvent-shielded and conformationally rigid, respectively.