NOXA-B and Mono_E1 gave low pAE values (Fig. & Fig. ) as 1:1 peptide/protein complexes. As complexes with MCL-1, the data suggest that the homodimeric scaffolds (Fig. & Fig. ) can form stable 2:2 peptide/protein assemblies, though the 2:1 peptide/protein complex might also be accessible. The CC-Di-A/CC-Di-B_S/MCL-1 ternary complex gave the lowest pAE score, indicating high confidence in this scaffold/protein combination (see Fig. ), consistent with our prior observation that inhibition of BID/MCL-1 interaction occurs only when both coiled-coil partners are present. Models of the complexes with CC-Tri_E1 indicate that this trimeric scaffold could recruit 1 or potentially 2 copies of MCL-1 but it is unlikely to accommodate 3 copies of the protein (Fig. & Fig. ) due steric congestion hindering packing of multiple copies of MCL-1 around the scaffold, and occlusion of the presented E1 binding motif (see Table -2). The data (Fig. & Fig. ) for the tetrameric scaffold with MCL-1 suggest that the 4:1 peptide/protein assembly is most favorable, whereas the 4:2 (Fig. ) and 4:3 assemblies are much less likely to form, and the 4:4 peptide/protein complex is unlikely to occur at all; this is likely dictated by sterics.