title: Inhibition by siomycin and thiostrepton of both aminoacyl-tRNA and factor G binding to ribosomes.
abstract: Siomycin, a peptide antibiotic that interacts with the 50S ribosomal subunit and inhibits binding of factor G, is shown also to inhibit binding of aminoacyl-tRNA; however, it does not impair binding of fMet-tRNA and completion of the initiation complex. Moreover, unlike other inhibitors of aminoacyl-tRNA binding (tetracycline, sparsomycin, and streptogramin A), siomycin completely abolishes the GTPase activity associated with the binding of aminoacyl-tRNA catalyzed by factor T(u). A single-site interaction of siomycin appears to be responsible for its effect on both the binding of the aminoacyl-tRNA-T(u)-GTP complex and that of factor G.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001665:Binding Sites; D005672:Fusidic Acid / Q000494:pharmacology; D006160:Guanosine Triphosphate; D006868:Hydrolysis; D010452:Peptide Biosynthesis; D010441:Peptide Chain Elongation, Translational; D010455:Peptides / Q000494:pharmacology; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors; D012343:RNA, Transfer / Q000037:antagonists & inhibitors* / Q000378:metabolism; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism*; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D010455:Peptides; D005672:Fusidic Acid; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D010744:Phosphoric Monoester Hydrolases; D013752:Tetracycline