Question

Ciprofloxacin inhibits DNA gyrase.

Erythromycin binds in front of the A site on the 50S ribosomal subunit.

Acyclovir is a guanine analog

Please tell me what steps in protein synthesis are inhibited by each drug.

Speculate as to which drug is moreeffective agains bacteria and why.

From your knowledge gained in this Unit which drug will have effect on the host's cells and why.

Answer 1

Ciprofloxacin inhibits the enzyme DNA gyrase and prevents replication of bactrial DNA during bacterial growth and reproduction. As the bacerial DNA cannot replicate it also inhibits the process of transcription and translation.

Erythromycin inhibits aminoacyl translocation by interfering with the transfer of tRNA from A site to P site. Therefore erythromycin inhibits the elongation of polypeptide chains during protein synthesis.

Acyclovir inhibits viral DNA synthesis by binding to the viral DNA polymerase leading to the termination of DNA synthesis. In turn the synthesis of proteins is also inhibited.

Erythromycin is more effective against bacteria because it binds to the A site on the 50S ribosomal subunit and inhibits the elongation of polypeptide chain. Erythromycin can be used specifically against bacteria because it does not exert any effect on eukaryotic ribosome.

Acyclovir will have effect on host cells because it can bind to the host cell DNA polymerase and inhibit it.