FIGURE 5.

DdiTLP3 and DdiTLP4 repair 5′-truncated mt-tRNA^Ile_CAU. (A) Schematic of phosphatase protection assay used with 5′-³²P-labeled tRNA to detect G₊₁ addition catalyzed by TLPs in the presence of ATP (0.1 mM) and GTP (1 mM). Only aminoacyl-acceptor stem sequences of the tRNAs are shown for clarity; lines indicate connection to the tRNA body. Expected products of RNase A/CIP treatment are shown beneath each tRNA. (B) The addition of G₊₁ assayed as shown in A with decreasing concentrations of each purified TLP (fivefold serial dilutions of each). Identities of the labeled species are indicated to the left of the figure. Lane −, no-enzyme control reaction. The maximum percent reaction products (sum of G₊₁ and AppG reaction products, if observed) formed by TLP2, -3, and -4 is indicated below each panel.