Practice question

Transfer RNA splicing removes intervening introns typically located one nucleotide three prime to anticodon loop in eukaryotic pre-transfer RNAs. Unlike messenger RNA splicing mediated by spliceosomes or group I self-splicing, tRNA introns are excised by protein enzymes: heterotetrameric splicing endonuclease complex SEN comprises Sen2, Sen34 catalytic subunits, Sen15, Sen54 structural, cutting at both splice sites leaving two halves with 2',3' cyclic phosphate and five prime hydroxyl. Ligase complex containing Trl1 phosphorylates hydroxyl and joins ends via healing and sealing steps, adding phosphate from GTP before ligation, producing mature spliced tRNA ready for modifications.