Talin1(W359A), but not talin1(L325R), impairs binding of talin to the β3 integrin tail. (A) Representation of the β3 integrin-talin complex structure (PDB 2H7E). Shown in red is the ribbon view of the β3 tail; light gray is the surface view of the talin F3 subdomain. Talin residues leucine 325 (L325) and tryptophan 359 (W359) are shown in green and blue, respectively. (B) Representative BiaCORE sensorgrams of THD binding to immobilized β3-integrin cytoplasmic domain (tail). Biotinylated β3 tail was immobilized to a neutravidin sensor chip. Indicated concentrations of wild-type or mutant talin head were injected, and response curves were measured as the difference between the experimental chamber and a reference chamber lacking immobilized β3 integrin. (C) Association rate constants (k_a), dissociation rate constants (k_d), and equilibrium dissociation constants (K_D) between β3-integrin tail and THD mean ± SEM (n = 3).