In a clever experiment preformed in 1962, a cystine already attached to its tRNA
ID: 63849 • Letter: I
Question
In a clever experiment preformed in 1962, a cystine already attached to its tRNA was chemically converted to an alanine. These “hybrid” tRNA molecules were then added to a cell free translation system from which the normal cycteine-tRNAs had been removed. When the reslting protein was analyzed, it was found that alanine had been inserted at every point in the protein chain where cysteine was supposed to be. What this experiment tells you about the role of aminoacyl-tRNA synthetases during the normal translation of the genetic code.
Explanation / Answer
This experiment tells us that aminoacyl-tRNA synthetase is necessary for attachment of the appropriate amino acid onto its tRNA. Many a times synthetase mediate a proofreading reaction to ensure high fidelity of tRNA charging; if the tRNA is found to be improperly charged, the aminoacyl-tRNA bond is hydrolyzed.