Qualitative analysis of the affinity of rLbRPA-1 for ssDNA. Panel A, scheme showing the experimental design. Panel B, follow up of the digoxigenin-labelled oligonucleotide (Oligo-Dig) in the different steps of the pull down assay. For each experiment, the analyzed samples were: 1, total amount of oligo-DIG used in the assay (12.5 ng); 2, unbound oligo-DIG after incubation with rLbRAP-1 containing beads; 3–5, Oligo-DIG presents in sequential washes; 6 and 7, 1/4 and 1/16 dilutions, respectively, of the eluted rLbRPA-1-oligo-DIG complexes. Green circles in samples two and six from mixture 1 (M1) indicate, respectively, unbound (2) and 1/4 of the eluted oligonucleotide (6), as signal intensity control, whilst red circles mark equivalent samples of the mixture 5 (M5) in which the oligo-DIG binding was compited by ssDNA.