Question

How does the ribosome verify correct tRNA–mRNA pairing?

Short answer

The ribosome verifies correct tRNA–mRNA pairing by binding with GTP.

Step-by-step solution

tRNA-mRNA pairing

Transfer RNAs have three nucleotide sequence arms called the anticodon arm that has a sequence complementary to the codons present in mRNA, according to this complimentary sequence they carry amino acids to the ribosome.

Verification of RNA pairing

The binding of GTP to the ribosomeverifies correct tRNA–mRNA pairingbecause it results in the hydrolysis of GTP, which push theanticodon ends of the two tRNA together with the mRNAs that are bounded to them, to move relative to the small ribosomal subunit to complete the elongation cycle. The positions occupied by the two tRNAs are:

• peptidyl–tRNA assumes the P/P state
• deacylated tRNA assumes the E/E state