title: How many EF-Tu molecules participate in aminoacyl-tRNA binding and peptide bond formation in Escherichia coli translation?
abstract: We have observed that two EF-Tu.GTP cycles are required to make one peptide bond during steady-state translation in an accurate and fast poly(U) translation system prepared from Escherichia coli. We have also found that there are two complexes of EF-Tu.GTP bound to one molecule of aminoacyl-tRNA under our experimental conditions. We suggest, on the basis of these data, that aminoacyl-tRNA enters the ribosomal A-site in a pentameric complex together with two EF-Tu and two GTP molecules. When the tRNA is delivered to the ribosome two GTP molecules are hydrolyzed. It is possible that the functional role of such an EF-Tu dimer is related to the function of the two L7/L12 dimers in the large ribosomal subunit.
authors.affiliation: Department of Molecular Biology, BMC, Uppsala University, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Ehrenberg
authors.forename: A M
authors.initials: AM
authors.lastname: Rojas
authors.forename: J
authors.initials: J
authors.lastname: Weiser
authors.forename: C G
authors.initials: CG
authors.lastname: Kurland
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D007700:Kinetics; D007935:Leucine-tRNA Ligase / Q000378:metabolism; D009154:Mutation; D010444:Peptide Elongation Factor Tu / Q000378:metabolism*; D010652:Phenylalanine-tRNA Ligase / Q000378:metabolism; D011072:Poly U / Q000235:genetics; D011485:Protein Binding; D014176:Protein Biosynthesis; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism
chemical_list: D012346:RNA, Transfer, Amino Acyl; D011072:Poly U; D006160:Guanosine Triphosphate; D010444:Peptide Elongation Factor Tu; D010652:Phenylalanine-tRNA Ligase; D007935:Leucine-tRNA Ligase