The antibacterial activity of<unk> s relies on the inhibition of bacterial DNA-dependent RNA synthesis. This is due to the high affinity of<unk> s for the prokaryotic RNA polymerase. The selectivity of the<unk> s depends on the fact that they have a very poor affinity for the analogous mammalian enzyme. Crystal structure data of the antibiotic bound to RNA polymerase indicates that<unk>  blocks synthesis by causing strong steric clashes with the growing oligonucleotide ("steric-occlusion" mechanism). If<unk>  binds the polymerase after the chain extension process has started, no inhibition is observed on the biosynthesis, consistent with a steric-occlusion mechanism. Single step high level resistance to the<unk> s occurs as the result of a single amino acid change in the bacterial DNA dependent RNA polymerase.
Rifamycin
Meropenem
Imipenem
Vancomycin
Spiramycin
Resistin
Ertapenem
Amikacin