FIGURE 2.

Bivalent model for the binding of RAP D1D2 to LRP1. A, schematic diagram of model in which LRP1 contains two binding sites for RAP D1D2; one containing two determinants on LRP1 (left) and a second containing only one determinant on LRP1 (right). B, scheme showing kinetic constants. Binding of D1D2 at site 1 on LRP1 allows for bivalent binding in which determinants on both the D1 domain and D2 domain interact with corresponding regions on LRP1 (Scheme I). In the model, LRP1 also contains a second site that can only interact with one determinant on D1D2 to form a monovalent complex (Scheme II).