Fig. 4. 441 forms complexes with HER2 and interlinks them, facilitates internalization and ultimately degradation of HER2 clusters.

a Multi-angle light scattering revealed that 441 formed complexes with HER2 ECD, resulting in higher-order oligomers of up to 2 MDa in size. b Binding studies of tetravalent 441, bivalent 841, and the antibody mixture TZB and hA21G to HER2 (see Supplementary Fig. 4 for detailed kinetic analysis) on DNA nanolevers of different densities (see colors) using the switchSENSE technology. A dependency of the on-rate on ligand density is seen for bivalent constructs (left column panels) but not for the tetravalent construct. Note that the response curves are normalized, reflecting the different number of antibodies bound at each surface density. The right-hand panels show a simulated surface, depicting a loss in interlinking of available HER2-DNA conjugates. c The derived association rate constants (n = 1, each derived from time course) are shown as well as the degree of crosslinking as calculated from the simulations in (b) (mean plus error bar SD, n = 100, from ten simulations on ten surfaces). The reduction of binding correlated well with a simulated surface, depicting a loss in interlinking of available HER2-DNA conjugates. Source data are available in the Source Data file.