Ln511/521 binding to D2-D3 linker mutants. (A) Three proteins, T233P, H235P, and Δ233-235 (darker shade), containing mutations within the domain 2 to 3 hinge were made. (B) Representative ELISA titrations of hinge region mutants to Ln511/521 in comparison with binding to the native protein. Standard deviations were less than 0.1 OD units for any point. (C) The sensorgrams of representative Biacore assays with these mutants are shown.