Figure 2. RPA, FAAP24, and Chk1 preferentially bind ssDNA and branched DNA.

The association of each of the indicated purified proteins with beads alone (No DNA) or to single-stranded (ss), double-stranded (ds), and branched, replication fork-like (fork) DNA bound to magnetic beads was analyzed by SDS-PAGE and immunoblotting. Each of the following proteins was analyzed for binding to each DNA structure: (A) RPA, (B) FAAP24, and (C) Chk1. Reactions were carried out as described in the Methods section. Experiments were repeated two to four times and the average binding values and standard deviations graphed. Input lane contains the lowest amount of protein used in each binding assay.