title: A mutant elongation factor Tu which does not immobilize the ribosome upon binding of kirromycin.
abstract: In the accompanying paper we have shown that polypeptide synthesis sustained by the mutant elongation factor EF-TuBO is inhibited by kirromycin. Here we have searched for the primary site of inhibition in the elongation cycle. It is demonstrated that in the presence of the antibiotic EF-TuBO can form a complex with aminoacyl-tRNA and GTP and that the complex is able to bind to ribosomes programmed with poly(U). Like its wild-type counterpart, EF-TuBO . GDP can form a quaternary complex with aminoacyl-tRNA and kirromycin but, unlike the wild-type quaternary complex, the mutant complex fails to associate with the ribosome. This explains the recessive nature of the tuf B mutation in cells producing kirromycin-resistant EF-TuA and EF-TuBO. It also suggests a mechanism for the inhibition by kirromycin of EF-TuBO-dependent polypeptide synthesis.
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D009154:Mutation; D010441:Peptide Chain Elongation, Translational; D010444:Peptide Elongation Factor Tu; D010445:Peptide Elongation Factors / Q000378:metabolism*; D011728:Pyridones / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D010445:Peptide Elongation Factors; D011728:Pyridones; D012346:RNA, Transfer, Amino Acyl; D006160:Guanosine Triphosphate; D010444:Peptide Elongation Factor Tu; C008536:mocimycin