FIG. 4.

Effect of Mn²⁺ and KCl on TNTase activity. (A) RdRp and TNTase assays using HΔ21. Both assays were performed with enzyme HΔ21 and RNA LE19. The nucleotides used in the reactions are listed above the autoradiogram. Asterisk (∗) identifies the radiolabeled nucleotide. r3 denotes the presence of GTP, ATP, and UTP in the reactions. Lengths of the reaction products (in nucleotides) are given between the two autoradiograms. Lanes + and −, reactions performed in the presence and absence of Mn²⁺, respectively. (B) RdRp and TNTase assays for BΔ23. The layout of the figure is identical to that in panel A. (C) Effects of increasing KCl concentration on RNA synthesis and TNTase activity of HΔ21. (D) Effects of increasing KCl concentration on RNA synthesis and TNTase activity of BΔ23.