Question

Choose the correct answer from the alternatives given :
Identify the labels A, B, C and Din the given structure of tRNA and select the correct option.

• A. A - Anticodon loop, B T$\Psi$C loop, C - AA binding site, D - DHU loop
• B. A - AA binding site, B - T$\Psi$C loop, C - Anticodon loop, D - DHU loop
• C. A - M binding site, B - DHU loop, C - Anticodon loop, D - T$\Psi$C loop
• D. A - M binding site, B - DHU loop, C - T$\Psi$C loop, D - Anticodon loop

Answer 1

Answer: (B)

A - AA binding site, B - T$\Psi$C loop, C - Anticodon loop, D - DHU loop

In tRNA, there is a TWC loop which contains pseudouridine and ribothymidine. The loop is the site for attaching to ribosomes. Another loop, DHU loop contains dihydrouridine. It is a binding site for aminoacyl synthetase enzyme. tRNA molecules have unpaired (single-stranded) CCAOH sequence at the 3 end. This is called amino acid binding site because the amino acid becomes covalently attached to adenylic acid or A of CCA sequence during polypeptide synthesis. Anticodon loop is made up of three nitrogen bases for recognizing and attaching to the codon of mRNA.

So, the correct answer is 'A - AA binding site, B - TΨC loop, C - Anticodon loop, D - DHU loop'.