Extended Data Fig. 6: Systematic replacement of intended network residues in crystal structure indicates their importance for mediating ABC specificity.

Colored cross-sections of the helical bundle base heterotrimer show hydrogen bond networks in the crystal structure (left), compared to (middle) Rosetta-preferred nonpolar residue substitutions, which shows broad SEC output (right) indicating ABC heterogeneity. The amino acid substitutions are shown in each SEC spectra and colored by the respective crystal structure coloring scheme: light gray for chain A, light cyan for chain B, and pink for chain C. The combination of all 3 replacements which results in a fully hydrophobic core, ‘sub_netall,’ shows the messiest SEC chromatogram seen for this design.