Unconventional decoding of the AUA codon as methionine by mitochondrial tRNA Met with the anticodon f 5 CAU as revealed with a mitochondrial in vitro translation system
Open Access
- 16 January 2009
- journal article
- research article
- Published by Oxford University Press (OUP) in Nucleic Acids Research
- Vol. 37 (5), 1616-1627
- https://doi.org/10.1093/nar/gkp001
Abstract
Mitochondrial (mt) tRNA(Met) has the unusual modified nucleotide 5-formylcytidine (f(5)C) in the first position of the anticodon. This tRNA must translate both AUG and AUA as methionine. By constructing an in vitro translation system from bovine liver mitochondria, we examined the decoding properties of the native mt tRNA(Met) carrying f(5)C in the anticodon compared to a transcript that lacks the modification. The native mt Met-tRNA could recognize both AUA and AUG codons as Met, but the corresponding synthetic tRNA(Met) lacking f(5)C (anticodon CAU), recognized only the AUG codon in both the codon-dependent ribosomal binding and in vitro translation assays. Furthermore, the Escherichia coli elongator tRNA(m)(Met) with the anticodon ac(4)CAU (ac(4)C 4-acetylcytidine) and the bovine cytoplasmic initiator tRNA(Met) (anticodon CAU) translated only the AUG codon for Met on mt ribosome. The codon recognition patterns of these tRNAs were the same on E. coli ribosomes. These results demonstrate that the f(5)C modification in mt tRNA(Met) plays a crucial role in decoding the nonuniversal AUA codon as Met, and that the genetic code variation is compensated by a change in the tRNA anticodon, not by a change in the ribosome. Base pairing models of f(5)C-G and f(5)C-A based on the chemical properties of f(5)C are presented.This publication has 75 references indexed in Scilit:
- Synthesis and investigation of the 5-formylcytidine modified, anticodon stem and loop of the human mitochondrial tRNAMetNucleic Acids Research, 2008
- Mechanism for expanding the decoding capacity of transfer RNAs by modification of uridinesNature Structural & Molecular Biology, 2007
- The crystal structure of yeast phenylalanine tRNA at 2.0 Å resolution: cleavage by Mg2+ in 15-year old crystalsJournal of Molecular Biology, 2000
- Stabilization of the anticodon stem-loop of tRNALys,3 by an A+-C base-pair and by pseudouridineJournal of Molecular Biology, 1999
- A Novel Modified Nucleoside Found at the First Position of the Anticodon of Methionine tRNA from Bovine Liver MitochondriaBiochemistry, 1994
- Conformational Rigidity of N4-Acetyl-2′-O-methylcytidine Found in tRNA of Extremely Thermophilic Archaebacteria (Archaea)Nucleosides and Nucleotides, 1992
- Animal Mitochondrial DNA: Structure and EvolutionInternational Review of Cytology, 1992
- C-A base pairs in transfer ribonucleic acids and codon-anticodon complexesJournal of Theoretical Biology, 1981
- Base pairing and fidelity in codon–anticodon interactionNature, 1976
- Codon—anticodon pairing: The wobble hypothesisJournal of Molecular Biology, 1966