Question

Ciprofloxacin, erythromycin, and acyclovir are used to treat infections.

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 DNA Gyrase and hence prevents unwinding of DNA. Erythromycin inhibits transfer of tRNA from A-site to P-site and thus inhibits polypeptide synthesis. Acyclovir may replace guanine and thus stops replication.

Ciprofloxacin is more effective since protein synthesis or DNA replication for the bacteria is inhibited since the function DNA gyrase does not occur.

All drugs have effects on host cell since since they act on cells non-specifically. They cannot differentiate between bacterial cell and host cell.

Acyclovir is used as a primary treatment for herpes disease which stops production of DNA. But Erythromycin stops polypeptide synthesis. To avoid virus to be prevalent, viral DNA replication should be stopped.