title: Identification of components of the streptomycin-binding center of E. coli MRE 600 ribosomes by photo-affinity labelling.
abstract: The [H3]-labelled photo-activated analog of streptomycin (photo-Sm) is obtained as a result of the streptomycin reaction with 2-nitro, 4-azidobenzoylhydrazide and subsequent reduction with NaBH34. The analog retains the functional activity of the initial antibiotic as judged by two criteria: (1) it binds only to the 30S subparticle of ribosomes and (2) it inhibits the factor-free ("non-enzymatic") PCMB-stimulated polyU-dependent system of translation (Gavrilova and Spirin, 1971). After irradiation of the reaction mixture containing photo-Sm and either the 30S or 50S subparticles of ribosomes under similar conditions, the analog covalently binds chiefly to the 30S subparticle. Irradiation of the photo-Sm mixture with whole 70S ribosomes  leads to a uniform distribution of a covalently bound label among the subparticles. A comparison of the effects obtained allows the conclusion that the analog is located on the interface of the ribosomal subparticles. In the 30S subparticle the photo-Sm attacks mainly the protein component (more than 95% of all the covalently bound label). The proteins labelled by photo-reaction are identified as S7 (main), S14 (additional) and S16/S17 (minor).
mesh_terms: D001665:Binding Sites; D002845:Chromatography; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects*; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*; D013307:Streptomycin / Q000031:analogs & derivatives / Q000494:pharmacology*
chemical_list: D012269:Ribosomal Proteins; D013307:Streptomycin