FIG. 2.
“Manganese suppressor” mutants display resistance to elevated Mn2+ in in vitro RT assays. Assays of recombinant WT and mutant Ty1 RT proteins were performed in 30-μl reaction mixtures [50 mM HEPES-KOH (pH 7.8), 3 mM DTT, 0.2 μM dGTP, 0.5 μCi of [α-32P]dGTP, 1 μg/ml oligonucleotide (dG)12-18, 10 μg/ml poly(rC)n, and the indicated concentrations of MgCl2 and/or MnCl2]. Reactions were set up on ice and carried out for 1 h at 22°C, and products were kept on ice while being spotted onto DE81 anion-exchange paper. The RT activity of manganese suppressor mutant proteins was normalized to WT RT activity, and N represents the number of times that each RT protein was assayed.