Single turnover kinetic studies of guanosine triphosphate hydrolysis and peptide formation in the elongation factor Tu-dependent binding of aminoacyl-tRNA to Escherichia coli ribosomes

• Published in: The Journal of biological chemistry Vol. 255; no. 23; pp. 11088 - 11090
• Main Authors: Thompson, R C, Dix, D B, Eccleston, J F
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 10.12.1980
• Subjects: Bacterial Proteins - metabolism; Escherichia coli - metabolism; Guanosine Triphosphate - metabolism; Hydrolysis; Kinetics; Peptide Chain Elongation, Translational; Peptide Elongation Factor Tu; Poly U; Ribosomes - metabolism; RNA, Transfer, Amino Acyl - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)70256-7

The rates of GTP hydrolysis and peptide formation during the reaction of Phe-tRNA . elongation factor Tu . GTP complex with acetyl-Phe-tRNA polyuridylate-programmed ribosomes have been measured. The GTPase reaction is second-order up to reactant concentrations of 0.2 microM and has a rate constant of 5 X 10(6) M-1 s-1 at 5 degrees C and 5 mM Mg2+, pH 7.2. The formation of peptide shows a lag phase and has a rate constant of 0.4 S-1 under these conditions. The results of a series of experiments between 5 degrees C and 25 degrees C show that GTP hydrolysis and peptide formation have Arrhenius activation energies of 13.1 and 15.3 kcal mol-1, respectively. The results indicate that these reactions proceed in vitro at rates comparable to those observed for protein biosynthesis in vivo, and that peptide bond formation occurs after GTP hydrolysis.