Abstract The details of species- spe- cific aminoacylation in Oryza sativa mitochondrial tRNATrp by bacterial and eukaryotic (cytoplasm) tryptophanyl-tRNA synthetases (TrpRS) were inves- tigated. Seven single or multi...Abstract The details of species- spe- cific aminoacylation in Oryza sativa mitochondrial tRNATrp by bacterial and eukaryotic (cytoplasm) tryptophanyl-tRNA synthetases (TrpRS) were inves- tigated. Seven single or multiple mutations of three bases (G73, U72, A 68) were made in O. sativa mi- tochondrial tRNATrp to the corresponding nucleotides present in human tRNATrp. In vitro transcripts of these mutant genes were tryptophanylated by Bacil- lus subtilis and human tryptophanyl-tRNA syntheta- ses (TrpRS), and the kinetic parameters were deter- mined. The results showed that the aminoacylation of seven mutant transcripts by B. subtilis TrpRS was 53.33%―99.79% less efficient than that by wild-type O. sativa mitochondrial tRNATrp, but was 4―330 times more efficient than that by human TrpRS. The mutant MPH7 (G73, U72 and C68 in O. sativa mito- chondrial tRNA were all replaced by the counterpart residues from human tRNATrp and showed a great change in aminoacylation efficiency. Our results in- dicate that the species-specific identity elements of O. sativa mitochondrial tRNATrp are similar to bacterial and eukaryotic (cytoplasm). They are mainly located at the discriminator base, the first and the fifth pairs of bases, the discriminator base G73, two bases in the acceptor stem G1/U72 and U5/A68. Our results also provide new data in support of the hypothesis that mitochondrial tRNATrp is of eubacterial origin.展开更多
基金supported by the Natural Science Foundation of Zhejiang Province(Grant No.302103).
文摘Abstract The details of species- spe- cific aminoacylation in Oryza sativa mitochondrial tRNATrp by bacterial and eukaryotic (cytoplasm) tryptophanyl-tRNA synthetases (TrpRS) were inves- tigated. Seven single or multiple mutations of three bases (G73, U72, A 68) were made in O. sativa mi- tochondrial tRNATrp to the corresponding nucleotides present in human tRNATrp. In vitro transcripts of these mutant genes were tryptophanylated by Bacil- lus subtilis and human tryptophanyl-tRNA syntheta- ses (TrpRS), and the kinetic parameters were deter- mined. The results showed that the aminoacylation of seven mutant transcripts by B. subtilis TrpRS was 53.33%―99.79% less efficient than that by wild-type O. sativa mitochondrial tRNATrp, but was 4―330 times more efficient than that by human TrpRS. The mutant MPH7 (G73, U72 and C68 in O. sativa mito- chondrial tRNA were all replaced by the counterpart residues from human tRNATrp and showed a great change in aminoacylation efficiency. Our results in- dicate that the species-specific identity elements of O. sativa mitochondrial tRNATrp are similar to bacterial and eukaryotic (cytoplasm). They are mainly located at the discriminator base, the first and the fifth pairs of bases, the discriminator base G73, two bases in the acceptor stem G1/U72 and U5/A68. Our results also provide new data in support of the hypothesis that mitochondrial tRNATrp is of eubacterial origin.
