Table 4.
Experimentally validated positive identity elements that are almost strictly conserved in all three domains of life including organellar tRNAs and viral TLSsa
| tRNA families | tRNA domains | ||
|---|---|---|---|
| Acceptor branch | Core region | Anticodon branch | |
| Cys | U73 | … | G34, C35, A36 |
| Ile | … | … | A35 |
| Leu | A 73 | largeVR | … |
| Met | A73 | … | … |
| Val | A73b | … | A35b |
| Trp | … | … | C34, C35, A36 |
| Tyr | A73b | … | G34, U35 |
| Ala | G 3· U 70 | … | … |
| Gly | G3–C70 | … | C 35, C36 |
| Pro | … | … | G35, G36 |
| Thr | G1–C72 | … | G34, U36 |
| Phe | A 73 | … | G 34, A35, A36 |
Of the 20 tRNA families designated by their amino acid identity, eight do not contain conserved determinants (Arg, Gln, Glu, His, Ser, Asp, Asn, Lys). The position of the determinants in the sequence of the tRNA acceptor branch, the core region and the anticodon branch is shown with standard numbering. aRare exceptions can be found at certain positions such as G3·U70 in organellar tRNAsAla, or G34 in eukaryal tRNAsThr; bdeterminants in TLSs. ‘…’ no data available. VR, variable region.