Figure 8.

Sequence- and structure-specific cleavage of G-rich single-stranded and G4 DNA by ScMre11p. (A) Reaction mixtures contained 1 nM ³²P-labeled G4 DNA and ScMre11p at 0.1, 0.25, 0.5, 0.6, 0.7, 0.8, 0.9 and 1 μM (lanes 5–12) in the presence of 5 mM Mn²⁺. Lane 1, the G ladder. Controls performed in the absence of ScMre11p (lane 4), Mn²⁺ (lane 3) or no additions (lane 2) is indicated on top of each lane. (B) Reaction mixtures contained 1 nM ³²P-labeled 38mer DNA and ScMre11p at 0.1, 0.25, 0.5, 0.6, 0.7, 0.8, 0.9 and 1 μM (lanes 4–11) in the presence of 5 mM Mn²⁺. Lane 12, G ladder. Controls performed in the absence of ScMre11p (lane 3), Mn²⁺ (lane 2) or no additions (lane 1) is indicated on top of each lane. Reaction products were analyzed on 20% PAGE in the presence of 7 M urea. (C) Summary of cleavage sites in G-rich single-stranded and G4 DNA by ScMre11p. The vertical arrows denote the position of cleavage. (D) Reaction mixtures contained 15 nM ³²P-labeled non-G-rich ssDNA and ScMre11p at 0.1, 0.25, 0.5, 0.75 and 1 μM (lanes 4–8) in the presence of 5 mM Mn²⁺. Lane 9, the G+A ladder. Controls performed in the absence of ScMre11p (lane 2), Mn²⁺ (lane 3) or no additions (lane 1) is indicated on top of each lane.