RctB is a RNA ligase that mediates the joining of broken tRNA-like stem-loop structures in case of tRNA damage. It probably participates to tRNA restriction-repair by ligating broken tRNA-like stem-loop structures with 2',3'-cyclic phosphate and 5'-OH ends to form a splice junction with a 2'-OH, 3',5'-phosphodiester [, , , ]. In worms, this protein has as a neuroprotective role in the age-dependent degeneration of dopamine neurons [].
RctB is a tRNA-splicing ligase from bacteria []. RctB homologues in eukaryotes represent the catalytic subunit of the tRNA-splicing ligase complex that acts by directly joining spliced tRNA halves to mature-sized tRNAs by incorporating the precursor-derived splice junction phosphate into the mature tRNA as a canonical 3',5'-phosphodiester. RctB may act as a RNA ligase with broad substrate specificity, and may function toward other RNAs [].
This entry represents a group of proteins that belong to the DNA polymerase beta superfamily, with closest affinities to the Minimal Nucleotide Transferase clade (MNT). They are found in diverse RNA repair genome contexts centred on both RtcB and Rnl-type (ATP-grasp fold) repair ligases []. Members of this family of bacterial proteins catalyze the transfer of nucleotide residues from nucleoside diphosphates or triphosphates into dimer or polymer forms.
