Illustration of a stably tethered structure made by the DNL method. Illustration of a stably tethered structure made by the DNL method. The α helices involved in the natural binding interaction of PKA (blue) and AKAPs (yellow) provide a preferred linker module for docking two types of entities, A and B, which are further locked by disulfide linkages (shown as interlocking rings). Such multivalent complexes always contain two copies of entity A. Chien-Hsing Chang et al. Clin Cancer Res 2007;13:5586s-5591s ©2007 by American Association for Cancer Research