GTP-dependent RNA ligase that is involved in tRNA splicing and RNA repair. Joins RNA with 2',3'-cyclic-phosphate or 3'-phosphate ends to RNA with 5'-hydroxy ends. a 3'-end 3'-phospho-ribonucleotide-RNA + a 5'-end dephospho-ribonucleoside-RNA + GTP = a ribonucleotidyl-ribonucleotide-RNA + diphosphate + GMP a 3'-end 2',3'-cyclophospho-ribonucleotide-RNA + a 5'-end dephospho-ribonucleoside-RNA + GTP + H2O = a ribonucleotidyl-ribonucleotide-RNA + diphosphate + GMP + H(+) Binds 2 manganese ions per subunit. Monomer. A member of the dormancy regulon. Induced in response to reduced oxygen tension (hypoxia), low levels of nitric oxide (NO) and carbon monoxide (CO). It is hoped that this regulon will give insight into the latent, or dormant phase of infection. Ligation proceeds through 3 nucleotidyl transfer steps, with 2',3'-cyclic phosphate termini being hydrolyzed to 3'-P termini in a step that precedes 3'-P activation with GMP. In the first nucleotidyl transfer step, RtcB reacts with GTP to form a covalent RtcB-histidine-GMP intermediate with release of PPi; in the second step, the GMP moiety is transferred to the RNA 3'-P; in the third step, the 5'-OH from the opposite RNA strand attacks the activated 3'-P to form a 3',5'-phosphodiester bond and release GMP. Belongs to the RtcB family.