Streptomycin Revisited: Molecular Action in the Microbial Cell

The key event for antimicrobial action begins when streptomycin binds to the 30S subunit (S12 protein) of a ribosome. Lysine 42 and lysine 87 are involved. It is proposed that antagonism of acetyl coenzyme A carboxylase by streptomycin results in faulty fatty acids, lipids and derivatives marked exclusively for cell membrane synthesis. Streptomycin-sensitive growing cells are fatally wounded when defective membranes leak K(+) ions, then amino acids, nucleotides, oligonucleotides and proteins as increasing amounts of streptomycin enter the cell.