FIGURE 8.

Effect of Mg²⁺ concentration on BM activities of BLM and RAD54 and helicase activity of BLM. A, the experimental scheme. The zigzagged line denotes the poly(dT)₃₀ region of the PX junction (oligonucleotide 71/169*/201/460). The 4-bp heterology region (denoted by the solid box) was designed to block protein-independent BM of the PX junction. The direction of BM is shown by the black arrow. The asterisks indicate ³²P-label. nt, nucleotide. B, BLM (20 nm) and RAD54 (200 nm) were added to PX junction (32 nm) in the presence of the indicated magnesium acetate concentrations. The reactions were carried out for 30 min at 37 and 30 °C for BLM and RAD54, respectively. The products of the helicase (forked DNA oligonucleotide 71/169*) and branch migration (3′-tailed DNA oligonucleotide 169*/460) reactions were separated in a 9% polyacrylamide gel (17:1).