Table 2. Effects of mutations in tRNAIle associated with diseases on structure, precursor 3′-tRNase processing and aminoacylation.
| Location in mitochondrial genome | Location in tRNA (nucleotide position) | Diseasea | Structural effect | Loss in 3′-tRNase processing efficiencyb | Loss in aminoacylation efficiency |
|---|---|---|---|---|---|
| A4269G | Acceptor stem (7) | CM | Stability decreasedc | 12.5 | 1.3d |
| T4274C | D-stem (12) | OP | – | 4.2 | 25d |
| G4284A | Connector (26) | Mixed | – | – | – |
| T4285C | Anticodon stem (27) | OP | – | 3.2 | 50d |
| A4295G | Anticodon loop (37) | CM | No changeb | 10.3 | 0.77e |
| G4298A | Anticodon stem (40) | OP | – | –f | >1000d |
| A4300G | Anticodon stem (42) | CM | – | 2.1 | 5e |
| G4309A | T-stem (51) | OP | Local changeb | 7.7 | – |
| A4317G | T-loop (59) | CM | No changeb | 10.0 | 3.75d |
| C4320T | T-stem (62) | CM | – | 4.2 | 0.6d |
aCM, cardiomyopathy; OP, ophtalmoplegia; Mixed, both cardiomyopathy and ophtalmoplegia.
bThis work.
cYasukawa et al. (25); (–) not determined.
eS. Kelley, personal communication.
fNot determined, but cleavage efficiency comparable to mutant A4300G.
Bold text is used to indicate those mutants which display the strongest reduction in either 3′-tRNase or aminoacylation efficiency, but not both (as discussed in text).