FIGURE 5.

Rescue of NmePrrC-R316W toxicity by tRNA repair enzymes. (Top panel) Growth of yeast cells bearing a CEN plasmid encoding galactose-regulated NmePrrC-R316W or the empty CEN vector (–) and either a 2μ TPI1-AtRNL plasmid, a 2μ TPI1-TRL1 plasmid, or a CEN plasmid expressing T4 Pnkp and Rnl1 as specified was assessed by spotting serial fivefold dilutions to minimal synthetic agar medium containing glucose or galactose. (Bottom panel) The tRNA ligases of plant (AtRNL) and yeast (Trl1) are composed of three discrete catalytic domains: an N-terminal ligase module; a central 5′-OH polynucleotide kinase module; and a C-terminal RNA 2′,3′ cyclic phosphodiesterase (CPD) module. The phage T4 tRNA repair system consists of separate sealing (Rnl1) and healing (Pnkp) enzymes.