Question

Isoleucine tRNA-synthetase uses a double-sieve mechanism to accurately produce Ile-tRNA and prevent synthesis of Val-tRNA. Which of the following pairs might have tRNA-synthetases that have a similar proofreading mechanism?

Asp-Phe

Glu-Arg

Ser-Thr

Tyr-Ala

Gly-Val

Answer 1

Ans- Glu-Arg

Explanation- tRNA synthetases that follow double-sieve model belong to classI tRNA synthetases. These tRNA synthetases follow two-step reaction to attach amino acid to tRNA. These tRNA have two sites- active site and other editing site. In the active site, the amino acid is attached to tRNA and in the editing site, any  incorrect amino acid added is removed by hydrolysis. Amino acid tRNA synthetases with double sieve model are- arginine, cysteine, glutamic acid, glutamine, isoleucine, leucine, methionine, tyrosine, tryptophan and valine.