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J Biol Chem. 2013 May 10;288(19):13917-28. doi: 10.1074/jbc.M113.460014. Epub 2013 Mar 28.

Elongation factor Ts directly facilitates the formation and disassembly of the Escherichia coli elongation factor Tu·GTP·aminoacyl-tRNA ternary complex.

Author information

1
Departments of Physiology and Biophysics, Weill Cornell Medical College, New York, New York 10065, USA.

Abstract

BACKGROUND:

Aminoacyl-tRNA (aa-tRNA) enters the ribosome in a ternary complex with the G-protein elongation factor Tu (EF-Tu) and GTP.

RESULTS:

EF-Tu·GTP·aa-tRNA ternary complex formation and decay rates are accelerated in the presence of the nucleotide exchange factor elongation factor Ts (EF-Ts).

CONCLUSION:

EF-Ts directly facilitates the formation and disassociation of ternary complex.

SIGNIFICANCE:

This system demonstrates a novel function of EF-Ts. Aminoacyl-tRNA enters the translating ribosome in a ternary complex with elongation factor Tu (EF-Tu) and GTP. Here, we describe bulk steady state and pre-steady state fluorescence methods that enabled us to quantitatively explore the kinetic features of Escherichia coli ternary complex formation and decay. The data obtained suggest that both processes are controlled by a nucleotide-dependent, rate-determining conformational change in EF-Tu. Unexpectedly, we found that this conformational change is accelerated by elongation factor Ts (EF-Ts), the guanosine nucleotide exchange factor for EF-Tu. Notably, EF-Ts attenuates the affinity of EF-Tu for GTP and destabilizes ternary complex in the presence of non-hydrolyzable GTP analogs. These results suggest that EF-Ts serves an unanticipated role in the cell of actively regulating the abundance and stability of ternary complex in a manner that contributes to rapid and faithful protein synthesis.

KEYWORDS:

Elongation Factor Ts; Elongation Factor Tu; G-proteins; Guanine Nucleotide Exchange Factor (GEF); Protein Synthesis; Ternary Complex; Transfer RNA (tRNA); Translation Regulation

PMID:
23539628
PMCID:
PMC3650427
DOI:
10.1074/jbc.M113.460014
[Indexed for MEDLINE]
Free PMC Article

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