title: Identification of 50S proteins at the peptidyl-tRNA binding site of Escherichia coli ribosomes.
abstract: Bromoacetyl-phenylalanyl-tRNA(phe) bound to 70S E. coli ribosomes reacts covalently with proteins of the 50S subunit. The major reactions are with proteins L2 and L27. In the presence of poly(U), 70S-bound bromoacetyl-phenylalanyl-tRNA(phe) can participate in peptidebond formation with phenylalanyl-tRNA(phe) or puromycin. Most of the products of these reactions are also found covalently attached to L2 and L27. Chloramphenicol and sparsomycin markedly inhibit the peptide-bond formation. These results strongly suggest that bromoacetylphenylalanyl-tRNA(phe) can function as a normal peptidyl-tRNA and that the 50S proteins, L2 and L27, are located in the peptidyl-tRNA binding site. The side reactions of bromoacetyl-phenylalanyl-tRNA(phe) are with one or more 50S proteins from the set L14-17, L6 and/or L11, and L26. These occur to a much less extent than the reactions with L2 and L27. Any functional significance of the side reactions is unknown.
mesh_terms: D000085:Acetates; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000302:isolation & purification*; D001665:Binding Sites; D001959:Bromates; D002701:Chloramphenicol / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000032:analysis*; D010649:Phenylalanine; D011485:Protein Binding / Q000187:drug effects; D011691:Puromycin / Q000494:pharmacology; D012343:RNA, Transfer / Q000378:metabolism*; D012263:Ribonucleosides / Q000494:pharmacology; D012270:Ribosomes / Q000032:analysis*; D014316:Tritium
chemical_list: D000085:Acetates; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001959:Bromates; D012263:Ribonucleosides; D014316:Tritium; D010649:Phenylalanine; D011691:Puromycin; D002701:Chloramphenicol; D012343:RNA, Transfer