| Class I aaRSs | Class II aaRSs |
| ValRS, LeuRS, IleRS, CysRS, | SerRS, ThrRS, ProRS, GlyRS, | MetRS, ArgRS, GluRS, GlnRS, | HisRS, AspRS, AsnRS, PheRS, | TyrRS, TrpRS, LysRS I | AlaRS, LysRS II | | SepRS, PylRS, hmPheRS |
| Signature motifs | HIGH, KMSKS | motif 1, motif 2, motif 3 |
| Architecture of catalytic domains | Rossmann fold | Antiparallel fold |
| Primary site of aminoacylation | | (except of PheRS) |
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