A potent inhibitor of protein synthesis that acts as an analogue of aminoacyl-tRNA is
a. Mitomycin Cb. Streptomycin
c. Nalidixic acid
d. Puromycin
The answer is d.
Puromycin is
virtually identical in structure to the 3′-terminal end of tyrosinyl-tRNA. In
both eukaryotic and prokaryotic cells, it is accepted as a tyrosinyl-tRNA analogue.
As such, it is incorporated into the carboxy-terminal position of a peptide at
the aminoacyl (A) site on ribosomes, causing premature release of the nascent
polypeptide. Thus, puromycin inhibits protein synthesis in both human and
bacterial cells. Streptomycin, like tetracycline and chloramphenicol, inhibits
ribosomal activity. Mitomycin covalently cross-links DNA, which prevents cell
replication. Rifampicin is an inhibitor of bacterial DNA-dependent RNA
polymerase.
