LOCATION OF THE STREPTOMYCIN RIBOSOMAL-BINDING SITE EXPLAINS ITS PLEIOTROPIC EFFECTS ON PROTEIN-BIOSYNTHESIS

Photoaffinity-labeling experiments using three nitroguaiacol ether streptomycin derivatives with spacers of different lengths between the antibiotic and the photoreactive moiety (8, 12 and 17 Å) allow us to: (1) unambigously locate the boundaries of the antibiotic binding site; and (2) test the topographical consistency of the photolabeling results. The streptomycin binding site is located in the interface between the ribosomal subunits, close to proteins S5 in the 30 S and to L11 in the 50 S ribosomal subunits. This location explains most of the antibiotic’s pleiotropic effects on protein biosynthesis, especially those related to the tRNA selection mechanism, and it also correlates with the location of the ribosomal components involved in the different streptomycin phenotypes. © 1994 Academic Press Limited.