Figure 5.
RNase H activity of WT and mutant HIV-1 RTs. Cleavage of a [32P]RNA/DNA substrate (R33B/20A) (30 nm) was carried out at 37 °C in the presence of the corresponding RT at 50 nm (active enzyme concentration). Aliquots were removed at 0.25, 0.5, 1, 5, 15, 30, and 60 min. A and B show RNase H cleavage patterns obtained in reactions carried out in the absence or in the presence of dNTPs, respectively. Arrows indicate the position of the uncleaved RNA substrate (33 nucleotides) and the hydrolysis products of 14, 17, 20, 25, and 26 nucleotides. The locations of cleavage sites on the RNA template are indicated below.