preferred_name: a tRNA with a 3' CC end + ATP => a tRNA with a 3' CCA end + diphosphate
preferred_name_lc: a trna with a 3' cc end + atp => a trna with a 3' cca end + diphosphate
label: a tRNA with a 3' CC end + ATP => a tRNA with a 3' CCA end + diphosphate
label_lc: a trna with a 3' cc end + atp => a trna with a 3' cca end + diphosphate