Toward a model for the interaction between elongation factor Tu and the ribosome.
In the elongation cycle of bacterial protein synthesis the interaction between elongation factor-Tu (EF-Tu).guanosine triphosphate (GTP), aminoacyl-transfer RNA (aa-tRNA), and messenger RNA-programmed ribosomes is associated with the hydrolysis of GTP. This interaction determines the selection of the proper aa-tRNA for incorporation into the polypeptide. In the canonical scheme, one molecule of GTP is hydrolyzed in the EF-Tu-dependent binding of aa-tRNA to the ribosome, and a second molecule is hydrolyzed in the elongation factor-G (EF-G)-mediated translocation of the polypeptide from the ribosomal A site to the P site. Substitution of Asp138 with Asn in EF-Tu changed the substrate specificity from GTP to xanthosine triphosphate and demonstrated that the EF-Tu-mediated reactions involved the hydrolysis of two nucleotide triphosphates for each Phe incorporated. This stoichiometry of two is associated with the binding of the correct aa-tRNA to the ribosome.
Weijland
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SDI n. 61840 du Centre National de la Recherche Scientifique, Laboratoire de Biochimie, Ecole Polytechnique, Palaiseau, France.
Parmeggiani
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D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D004926:Escherichia coli; D020963:GTP Phosphohydrolase-Linked Elongation Factors / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D010441:Peptide Chain Elongation, Translational; D010444:Peptide Elongation Factor Tu / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*
D001426:Bacterial Proteins; D012346:RNA, Transfer, Amino Acyl; D006160:Guanosine Triphosphate; D020963:GTP Phosphohydrolase-Linked Elongation Factors; D019204:GTP-Binding Proteins; D010444:Peptide Elongation Factor Tu