FIG 5.

Cleavage of chimeric RNA-DNA junction substrates. Reaction mixtures (10 μl) containing 50 mM Tris-HCl (pH 8.0); 50 mM NaCl; 10 mM MgCl₂; 1 mM DTT; 200 fmol ³²P-labeled 24-mer duplex R24, R12D12, or D12R12 (shown at the bottom, with the ³²P label denoted by a dot and the ribonucleotides shaded black); and 0 or 4 fmol RnhC was incubated for 20 min at 37°C. The products were resolved by urea-PAGE and visualized by autoradiography. Alkaline hydrolysis ladders of the ³²P-labeled R24, R12D12, and D12R12 strands were analyzed in parallel in the three lanes on the left (⁻OH). Major and minor cleavage sites are denoted by large and small arrowheads, respectively.