Question

Explain the way of action of antibiotics known as aminoglycosides, tetracyclines and macrolides. Give detailed answer.

Answer 1

Mode of Action of Aminoglycosides – The antibiotic is used against bacterial infection and it does so by the mechanism of inhibition of proteins. It is bactericidal in nature and broad spectrum antibiotic but not effective against anaerobic bacteria. Once it moves inside the bacterial cell, it tends to bind to the 30S ribosomal sub-unit and leads to misreading of the genetic code. On binding to the 30S ribosomal sub-unit, it interferes with the normal protein synthesis in the bacteria.

Mode of action of Tetracycline – The antibiotic inhibits the bacterial infection by inhibiting the synthesis of protein. The antibiotic prevents the binding of the aminoacyl t-RNA that carries the amino acid which needs to be added to the growing polypeptide chain. As it inferferes binding of the aminoacyl t-RNA to the 30S ribosomal subunit in the mRNA translation complex, it inhibits the steps in protein biosynthesis.

Mode of action of Macrolides – The mode of mechanism of macrolides is still not very crystal clear but it is known that it inhibits the bacterial synthesis through the protein synthesis. It binds to the 50S ribosomal subunit with a specific target in the 23S ribosomal RNA molecule and number of other ribosomal subunits.