title: Monoclonal antibodies to epitopes in both C-terminal and N-terminal domains of Escherichia coli ribosomal protein L7/L12 inhibit elongation factor binding but not peptidyl transferase activity.
abstract: Two monoclonal antibodies against different epitopes in Escherichia coli ribosomal protein L7/L12, one within residues 74-120 and the other within residues 1-73, shown before to inhibit the binding of EF-G, have been tested for their effects on the binding to E. coli ribosomes of EF-Tu-aminoacyl-tRNA-GTP ternary complex and on peptidyl transferase activity. Both antibodies inhibit the binding of ternary complex and EF-Tu-dependent GTPase but have no inhibitory effect on peptidyl transferase activity. The inhibition of binding of both elongation factors is indicative of overlapping binding sites for EF-G and EF-Tu. The inhibition by both antibodies implies the contribution of both domains of L7/L12 to this binding site. This implies the location of one or more of the C-terminal domains of L7/L12 on the body of the 50S subunit. The absence of any inhibition of peptidyl transferase activity shows distinct separation of this site from the factor binding site.
mesh_terms: D000217:Acyltransferases / Q000378:metabolism*; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D001426:Bacterial Proteins / Q000378:metabolism*; D000939:Epitopes / Q000032:analysis; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D020963:GTP Phosphohydrolase-Linked Elongation Factors / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006165:Guanylyl Imidodiphosphate / Q000378:metabolism; D007700:Kinetics; D010444:Peptide Elongation Factor Tu / Q000378:metabolism*; D010445:Peptide Elongation Factors / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D012269:Ribosomal Proteins / Q000276:immunology / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D001426:Bacterial Proteins; D000939:Epitopes; D010445:Peptide Elongation Factors; D012346:RNA, Transfer, Amino Acyl; D012269:Ribosomal Proteins; D006165:Guanylyl Imidodiphosphate; C016700:ribosomal protein L7-L12; D006160:Guanosine Triphosphate; D000217:Acyltransferases; D020963:GTP Phosphohydrolase-Linked Elongation Factors; D010444:Peptide Elongation Factor Tu