Question

In a study involving a cell-free translation system from coli, the polyribonucleotide AUGUUUUUUUUUUUU directs the synthesis of the oligopeptide fMet-Phe-Phe-Phe-Phe. In the presence of a new class of translation-targeting antibiotics that bind to the large ribosomal subunit, the ribosomal complex forms, the initiator tRNA binds the mRNA, the second tRNA enters the A site of the ribosome, but no peptide bonds form. Which of the following is a likely function of these new antibiotics?
a. Blocks peptidyl transferase activity
b. Inhibits tRNA aminoacyl synthetase function
c. Inhibits ribosomal translocation along the mRNA
d. Prevents anticodon base-pairing with the codon
e. Blocks binding of the Shine-Dalgarno box to the rRNA

Answer 1

Answer:

c. Inhibits ribosomal translocation along the mRNA.

Explanation:

Initiator tRNA is thought to bind directly to P-site of small ribosomal sub unit. These tRNA are positioned at P site and remain attached to tRNA located at this site. Initiation factor helps to mediate this event.