Question

Class II amino acyl tRNA synthetase transfers the amino acids to the tRNA __________

(a) 3’-OH of the A base

(b) 3’-OH of the C base

(c) 2‘-OH of the A base

(d) 2’-OH of the C base

The question was asked in an interview for job.

The question is from TRNA topic in section Gene Expression : Translation of Cytogenetics

Answer 1

Correct option is (c) 2‘-OH of the A base

For explanation I would say: Class II aminoacyl tRNA synthetase transfers the amino acid to the 2’-OH of the tRNA. There is a quick equilibrium between the 2’ and the 3’-OH. On the other hand class I amino acyl tRNA synthetase transfers it to the 3’-OH.