Structure of mitochondrial tRNA.

Some mitochondrial (mt) tRNAs are presumed to have unusual secondary structures on the basis of DNA sequence analyses. However there are few tRNAs whose structures have been investigated at RNA level. Thus we isolated some mt tRNAs to investigated their structures and also synthesized mt tRNA by run-off transcription. In these experiments, following results have been obtained. 1) Bovine mt tRNA(Ser)(AGY) needs the interaction between the T-loop and D-arm for its aminoacylation activity. 2) The secondary structure of bovine mt tRNA(Ser)(UCN) is difficult from that predicted previously from its gene. 3) It has been confirmed by the hybridization using oligonucleotide probes that some Ascaris suum mt tRNAs possessing the unusual T-arms actually exist in its mitochondria.