Figure 2.

RPA prevents the formation of G4 structures by preempting ssDNA before its folding

(A–F) The representative FRET traces of G4 DNA substrates prepared in 25 mM Tris-HCl, pH 7.5 upon the addition of 200 mM KCl and 5 mM MgCl₂ (panel 1) and RPA in 200 mM KCl with 5 mM MgCl₂ (panels 2–4). The red arrow indicates the addition of ions or proteins, i.e., the start of the flow to the ∼25 μL flow cell.

(G) The fractions of FRET traces showing different types of changes upon the addition of RPA. All the single-molecule traces in each experiment were examined and classified into different types.