Requirement of modified residue m1A9 for EF-Tu binding to nematode mitochondrial tRNA lacking the T arm

Most of nematode mitochondrial (mt) tRNAs lacking the T arm have 1-methyladenosine (m1A) at position 9. To investigate the effect of m1A, we constructed a nematode Ascaris suum mt tRNA(Met) containing only m1A9 as the modified nucleoside by means of molecular surgery. Although the unmodified A. suum mt Met-tRNA(Met) did not bind to nematode mt EF-Tu, the m1A9-containing tRNA bound to the EF-Tu, suggesting that m1A at position 9 is necessary for binding of nematode mt tRNAs lacking the T arm to the EF-Tu, probably because of maintenance of the L-shape-like structure or interaction with the C-terminal amino acid residues of the EF-Tu.