Figure 5

Double stranded DNA end preferences of SXT-Exo. SXT-Exo (2 pmol of trimers) in Tris-HCl (25 mM, pH7.4), 0.5 mM MnCl₂, 50 mM NaCl; was incubated at 37°C for 30 mins with: i) 5'-phosphorylated linear dsDNA with 4 nt 3'-overhangs (PstI-linearized pUC18, black shaded circles); ii) 5'-hydroxylated linear dsDNA with 4 nt 3'-overhangs (dephosphorylated PstI-linerarized pUC18, un-shaded circles); iii) 5'-phosphorylated blunt-ended dsDNA (SspI-linerized pUC18, shaded inverted triangles); or iv) 5'-phosphorylated linear dsDNA with 4 nt 5'-overhangs (BamHI-linearized pUC18, un-shaded green triangles). Aliquots were removed at 1, 2, 5, 10, 20 and 40 minutes; quenched, then dsDNA levels were quantified using the PicoGreen reagent. Graphs show the the mean values ± standard deviation. See methods for detailed experimental procedures.