Some common antibiotics and their effects

Last Updated on November 9, 2020 by Sagar Aryal

Antibiotics Definition

When we are ill with a microorganism infection, Docter suggest us to use a particular type of antibiotics, here we have to first know what is antibiotic, and how it works against particular bacteria / microbial infections. Antibiotics are a group of medicine which inhibit the growth of microbes/ bacteria and destroy it by a particular type of action. In other words, we can say that antibiotics are substances that act against micro-organism by blocking their physiology such as translation, transcription, and cell wall biosynthesis.

Some common antibiotics and their effects

Name and their particular effects

Penicillin

It affects bacteria and kills them by inhibiting cell wall biosynthesis in bacteria. Penicillin inhibits the transpeptidase which catalyzes the cross-linking of peptidoglycan. So penicillin inhibits the cross-linking of peptidoglycan.

Tetracycline

Tetracycline affects bacteria by inhibiting elongation in bacterial protein synthesis. These antibiotics inhibit attachment of aminoacyl-tRNA to A site of 30S ribosomes, thus inhibit elongation.

Streptomycin

Inhibit initiation of protein synthesis. Streptomycin inhibits the binding of fmet – tRNA to 16S rRNA of the 30S subunit of the ribosome and thus interferes with the binding of fmet-tRNA and leads to inhibition of initiation of protein synthesis.

Erythromycin

It thought to inhibit the binding of the 50S subunit and block the tunnel where the polypeptide string is supposed to exit. This leads to inhibition of translation.

Chloramphenicol

It binds to the 23S rRNA of the 50S subunit and blocks the peptide bond formation, thus inhibits protein synthesis. The 23S rRNA of the 50S subunit and 28S rRNA of the 60S subunit are ribozyme and act as peptidyl transferase, antibiotics chloramphenicol bind with 23S rRNA of 50S subunit and inhibit peptidyl transferase activity in prokaryotes, leads to inhibition elongation of protein synthesis.

Cycloheximide

These antibiotics interfere with the translocation process during eukaryotic protein synthesis, thus inhibit translation elongation in eukaryotes. This secreted by the bacteria Streptomyces griseus.

Puromycin

It is a structural analog of 3’ end of aminoacyl tRNA but has an amide bond rather than ester bond aminoacyl tRNA. It binds to A site of ribosomes like aminoacyl tRNA and peptidyl transferase link the peptide of peptidyl tRNA of P site to puromycin and then it passes to P site and no further peptidyl transfer takes place as enzyme can’t break amide bond and thus peptidyl puromycin fall off the ribosomes. It needs a high concentration of puromycin for protein synthesis inhibition because once peptidyl puromycin falls off from ribosomes can’t bind again, binding needs fresh puromycin.

Vancomycin

It inhibits the second stage of cell wall synthesis, vancomycin prevents incorporation of NAM (N-acetylmuramic acid and NAG (N-acetylglucosamine) which is the building block of peptidoglycan. So the cell wall of bacteria became more permeable and cellular content of bacteria leak out leads to the death of bacteria.

Actinomycin D

It inhibits the transcription of mRNA. Actinomycin D binds to the minor groove of DNA at GC by hydrophobic interaction, this stable interaction prevents the unwinding leads to inhibition of DNA dependent RNA polymerization.

Rifampicin

Rifampicin inhibits transcription by binding with bacterial DNA dependent RNA polymerase. It binds with beta-subunit of bacterial RNA polymerase. This antibiotic is mainly used against tuberculosis causing bacteria (Mycobacterium tuberculosis), and it is also effective against some virus-like vaccinia virus. This antibiotic is produced from the soil bacterium Amycolatopsis rifamycinica.

References and Sources

  • 3% – https://study.com/academy/lesson/inhibitors-of-protein-synthesis-aminoglycosides-tetracyclines-chloramphenicol-macrolides.html
  • 3% – https://answers.yahoo.com/question/index?qid=20081025183822AAVjqbj
  • 2% – https://www.slideshare.net/DebanganaMoitra/streptomycin
  • 2% – https://pubmed.ncbi.nlm.nih.gov/7372662/
  • 1% – https://www.serva.de/enDE/ProductDetails/22_10710_Actinomycin_D_cryst_research_grade_html
  • 1% – https://www.sciencedirect.com/science/article/pii/S0092867401002860
  • 1% – https://www.jagranjosh.com/general-knowledge/list-of-important-antibiotics-its-source-and-action-1476085418-1
  • 1% – https://sciencing.com/types-cells-bacteria-6817651.html
  • 1% – https://quizlet.com/273971139/vancomycin-inhibitors-of-cell-wall-synthesis-iii-flash-cards/
  • 1% – https://en.wikipedia.org/wiki/Antibiotic

Leave a Comment