RGDS-survivin binding. A: Increasing doses of purified human-recombinant survivin (0.3 to 5 μg/spot) were immobilized onto membrane and incubated with bt-RGDS in the presence of un-labeled peptide, as competitor (top). A representative experiment of two different assays, is shown. Densitometry quantification is reported (bottom). B: Bt-RGDS binding to recombinant GST-fusion survivin and to N-terminus (Met1-Gly99) or C-terminus (Lys90-Asp142) fragments (175 mM) was evaluated by solid-phase assay (SPA). Proteins were immobilized onto plastic and were incubated with increasing doses of bt-RGDS (1.75 nM to 1.75 mM) in the presence of an excess of un-labeled RGDS. Three independent experiments were performed.