Codon reading patterns in Drosophila melanogaster mitochondria based on their tRNA sequences: a unique wobble rule in animal mitochondria

Mitochondrial (mt) tRNA(Trp), tRNA(Ile), tRNA(Met), tRNA(Ser)GCU, tRNA(Asn) and tRNA(Lys) were purified from Drosophila melanogaster (fruit fly) and t heir nucleotide sequences were determined. tRNA(Lys) corresponding to both AAA and AAG lysine codons was found to contain the anticodon CUU, C34 at th e wobble position being unmodified. tRNA(Met) corresponding to both AUA and AUG methionine codons was found to contain 5-formylcytidine (f(5)C) at the wobble position, although the extent of modification is partial. These res ults suggest that both C and f(5)C as the wobble bases at the anticodon fir st position (position 34) can recognize A at the codon third position (posi tion 3) in the fruit fly mt translation system, tRNA(Ser)GCU Corresponding to AGU, AGC and AGA serine codons was found to contain unmodified G at the anticodon wobble position, suggesting the utilization of an unconventional G34-A3 base pair during translation. When these tRNA anticodon sequences ar e compared with those of other animal counterparts, it is concluded that ei ther unmodified C or Gi at the wobble position can recognize A at the codon third position and that modification from A to t(6)A at position 37, 3'-ad jacent to the anticodon, seems to be important for tRNA possessing C34 to r ecognize A3 in the mRNA in the fruit fly mt translation system.