Question

Aminoacyl-tRNAs display high fidelity, even for amino acids such as threonine and serine that have very similar side chains. Present a model for the proofreading activity of aminoacyl-tRNA synthetases.

Answer 1

Aminoacyl tRNA synthetase (aaRS) enzyme is essential for translation i. e. catalyse the binding of tRNA to their respective amino acid (cognate amino acid).

aaRS prevents the attachment of incorrect amino acids to tRNA, thereby enhancing the accuracy of translation. That's how increasing the fidelity of protein synthesis.

If in case tRNA synthetase cannot distinguish between structurally similar amino acids and thus results in attachment of non cognate or incorrect amino acid. So this noncognate aminoacyl adenylate amd amino acyl tRNA will be destroyed by hydrolytic activities of enzyme.