FIG. 6.

Extension of an unblocked DNA primer 25PGA by mutant RTs M41L/T215Y and M41L/T215Y/P272A/R277K/T286A in the presence of an RNA template (31rna). Reactions were carried out with template-primer concentrations of 1 nM (left panel) and 10 nM (right panel) in 50 mM HEPES buffer (pH 7.0) containing 15 mM NaCl, 15 mM magnesium acetate, 130 mM potassium acetate, 1 mM dithiothreitol, 5% (wt/vol) polyethylene glycol 6000, and 200 μM each dNTP except dATP, which was supplied at 2 μM. The RT concentration used in these assays was 3 nM (active site concentration). P, primer; F, full-length product.