Streptomycin is a broad-spectrum antibiotic belonging to the class of drugs called Aminoglycosides. It is a natural product of bacteria from the genus Streptomyces.
Streptomycin inhibits protein synthesis in bacteria by binding to the 16S rRNA during the formation of the initiation complex. With Streptomycin attached to the rRNA, the first tRNA needed for starting protein synthesis (fmet-tRNA) cannot be added and the 50S subunit cannot be added. Thus, the process normally followed to form the initiation complex required to start protein synthesis cannot be accomplished. No protein synthesis, no viability for the cell.