The bases of the tRNA anticodon loop are independent by genetic criteria.
AUTOR(ES)
Smith, D
RESUMO
We employed two methods to study the translational role of interactions between anticodon loop nucleotides. Starting with a set of previously constructed weakly-suppressing anticodon loop mutants of Su7, we searched for second-site revertants that increase amber suppressor efficiency. Though hundreds of revertants were characterized, no second-site revertants were found in the anticodon loop. Second site reversion was detected in the D-stem, thereby demonstrating the efficacy of the search method. As a second method for detecting interactions, we used site-directed mutagenesis to construct multiple mutations in the anticodon loop. These multiple mutants are very weak suppressors and have translational activities that are equal to or lower than that predicted for the independent action of single mutations. We conclude that although the anticodon loop sequence of Su7 has an optimal structure for the translation of amber codons, we find no evidence that interactions between loop bases can enhance translational efficiency.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=340888Documentos Relacionados
- Construction of a composite tRNA gene by anticodon loop transplant.
- Anticodon loop size and sequence requirements for recognition of formylmethionine tRNA by methionyl-tRNA synthetase.
- Involvement of the size and sequence of the anticodon loop in tRNA recognition by mammalian and E. coli methionyl-tRNA synthetases.
- Glycine tRNA mutants with normal anticodon loop size cause -1 frameshifting.
- The nucleotide in position 32 of the tRNA anticodon loop determines ability of anticodon UCC to discriminate among glycine codons.