title: Identification of a ribosomal protein necessary for thiostrepton binding to Escherichia coli ribosomes.
abstract: A ribosomal protein necessary for thiostrepton binding to Escherichia coli ribosomes has been identified using the following criteria: 1. A loss in the thiostrepton binding ability of the ribosome was correlated with the selective removal of ribosomal protein L11. This was achieved by a comparison of the thiostrepton binding ability of 50 S ribosomal subunits treated with 1 M NH4C1 and 50% ethanol at 37 degrees which still contained protein L11, and subunits treated successively at 0 degrees and 37 degrees in the same medium, from which protein L11 had been removed. 2. The thiostrepton binding ability of a ribosomal core containing only seven proteins, produced by treatment of 50 S subunits with 4 M LiC1, was fully restored by the rebinding of protein L11, obtained by Sephadex G-100 fractionation of the 1 M LiC1 split protein fraction from 50 S subunits. In addition, treatment of the 1 M LiC1 split protein fraction with an IgG specific for protein L11, uniquely inhibited the restoration of activity. 3. Thiostrepton binding to the 4 M LiC1 core, reconstituted with the 1 M LiC1 split protein fraction, was blocked by treatment with a monovalent antibody fragment (Fab) prepared against protein L11, but not by treatment with antibodies specific for the proteins of the 4 M LiC1 core. We conclude, therefore, that protein L11 is required for the ribosomal binding of thiostrepton.
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D000937:Antigen-Antibody Reactions; D001426:Bacterial Proteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D001665:Binding Sites; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000032:analysis / Q000378:metabolism*; D007700:Kinetics; D008094:Lithium; D010455:Peptides / Q000378:metabolism*; D011485:Protein Binding; D011955:Receptors, Drug; D012270:Ribosomes / Q000032:analysis; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D010455:Peptides; D011955:Receptors, Drug; D008094:Lithium