Translation is a complex process and it has become a favorite target for inhibition by antibiotics. Antibiotics are the substances produced by bacteria or fungi which inhibit the growth of other organisms. Majority of the antibiotics interfere with the bacterial protein synthesis and are harmless to higher organisms. This is due to the fact that the process of translation sufficiently differs between prokaryotes and eukaryotes. The action of a few important antibiotics on translation is described next.
- Streptomycin : Initiation of protein synthesis is inhibited by streptomycin. It causes misreading of mRNA and interferes with the normal pairing between codons and anticodons.
- Tetracycline : It inhibits the binding of aminoacyl tRNA to the ribosomal complex. In fact, tetracycline can also block eukaryotic protein synthesis. This, however, does not happen since eukaryotic cell membrane is not permeable to this drug.
- Puromycin : This has a structural resemblance to aminoacyl tRNA. Puromycin enters the A site and gets incorporated into the growing peptide chain and causes its release. This antibiotic prevents protein synthesis in both prokaryotes and eukaryotes.
- Chloramphenicol : It acts as a competitive inhibitor of the enzyme peptidyltransferase and thus interferes with elongation of peptide chain.
- Erythromycin : It inhibits translocation by binding with 50S subunit of bacterial ribosome.
- Diphtheria toxin : It prevents translocation in eukaryotic protein synthesis by inactivating elongation factor eEF2.
- Cycloheximide : It blocks translocation in eukaryotic ribosomes, making a useful laboratory tool for blocking protein synthesis in eukaryotic cells.
- Other aminoglycoside antibioticssuch as neomycin, kanamycin, and gentamycin interfere with the decoding site located near nucleotide 1492 in 16S rRNA of the 30S subunit