Transfer RNA in Decoding and the Wobble Hypothesis

Mick F Tuite, University of Kent, Canterbury, Kent, UK

Published online: April 2001

DOI: 10.1038/npg.els.0001497

The translation of the genetic code stored in messenger RNA requires significantly fewer tranfer RNAs than there are codons. This is achieved through an increased flexibility in the allowable base-pair interactions between the mRNA and tRNA involving the third position of the codon. The rules governing the allowable base-pair interactions were originally summarized in Crick's ‘wobble hypothesis’.

Keywords: wobble hypothesis; tRNA; mRNA decoding; codon recognition

Figure 1. mRNA–tRNA interactions involve base pairing between the anticodon of the transfer RNA (tRNA) and the messenger RNA (mRNA) codon. (a) Standard depiction of the two dimensional ‘clover-leaf’ structure of a tRNA molecule. (b) An Arg-inserting tRNA with a UCU anticodon can translate both the AGA codon by standard base-pair interactions at all three positions, and the AGG codon by a non-Watson and Crick pairing in the third ‘wobble’ position of the codon.
Figure 2. The three dimensional structure of a transfer RNA (tRNA) molecule. tRNA molecules take up an L-shaped structure due to a variety of intramolecular base interactions. The anticodon is present in a large unpaired region of the molecule with the three bases of the anticodon all pointing approximately in the same direction. The ‘U turn’ base (U33) immediately adjacent to the anticodon is indicated.
Figure 3. Wobble base-pair interactions that occur between the first base of the anticodon (left) and the third base of the codon (right).
Figure 4. Translation of the UGA codon in Escherichia coli by a Trp-inserting tRNA. The relative, approximate efficiencies of UGG/UGA decoding by (a) the wild-type transfer RNA (tRNA), (b) a nonsense suppressor mutant of the tRNA in which C34 has been replaced by U34; and (c) a novel suppressor variant of the tRNA with G24 replaced by A24.
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 References
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 Further Reading
    Eggertsson G and Soll D (1988) Transfer ribonucleic acid-mediated suppression of termination codons in Escherichia coli. Microbiological Reviews 52: 354–374.
    book Osawa S (1995) Evolution of the Genetic Code. Oxford: Oxford Science Publications.
    book Soll D and RajBhandary UL (1995) tRNA Structure, Biosynthesis and Function. Washington DC: ASM Press

Related Sub-Topics:

Translation and Protein synthesis | Translation of RNA | RNA Structure and Function | Noncoding RNA | Genetic Code | Biomolecular Interactions | Nucleic Acids: Structure, Function, Metabolism
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Article Title: Transfer RNA in Decoding and the Wobble Hypothesis
 
How to Cite close
Tuite, Mick F(Apr 2001) Transfer RNA in Decoding and the Wobble Hypothesis. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0001497]