Deadenylation activity of T4 RNA ligase 2 truncated mutants . 5'-adenylated DNA adapters were incubated with an excess of ligase (13.8 pmol), and 12.5% PEG 8000 at 16°C overnight. Oligonucleotide substrates are depicted schematically above the gel. The contents of each sample were resolved on denaturing 15% acrylamide gels and stained with SYBR Gold to visualize nucleic acid. Deadenylation of the DNA adapter (loss of 5'-App) is indicated by a band shift of ~1 nt towards the bottom of the gel. Rnl1 = T4 RNA ligase 1, Rnl2 = T4 RNA ligase 2, Rnl2tr = T4 RNA ligase 2 truncated, Rnl2 +MBP = T4 RNA ligase 2 truncated attached to an N-terminal maltose binding protein tag. All mutations indicated are substitutions in T4 Rnl2tr + MBP.