title: Localization of Lys-51 of L7/L12 on 50S ribosomes from Escherichia coli.
abstract: Ribosomal protein L7/L12 from Escherichia coli was modified specifically at Lys-51 with 4-(6-formyl-3-azido-phenoxy)butyrimidate. Reconstitution of ribosomal cores, lacking L7/L12, with imidate-modified L7/L12 resulted in back formation of 50S particles which were fully active in elongation-factor-dependent processes. By use of the formylazidophenoxy moiety as hapten, the position of Lys-51 of L7/L12 on the 50S ribosome was determined by immune electron microscopy. The results show that an L7/L12 dimer is present in the L7/L12 stalk in such a way that Lys-51 is located at the far cytoplasmic end of the stalk. The experimental data are discussed in relation to a proposed model for the L7/L12 dimer.
mesh_terms: D001426:Bacterial Proteins / Q000302:isolation & purification*; D055598:Chemical Phenomena; D002621:Chemistry; D004926:Escherichia coli / Q000378:metabolism* / Q000648:ultrastructure; D007120:Immunochemistry; D007074:Immunoglobulin G / Q000302:isolation & purification; D008239:Lysine / Q000302:isolation & purification*; D008854:Microscopy, Electron; D012269:Ribosomal Proteins / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; D007074:Immunoglobulin G; D012269:Ribosomal Proteins; C016700:ribosomal protein L7-L12; D008239:Lysine