Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Biol Chem. 2010 Jul 30;285(31):23810-7. doi: 10.1074/jbc.M110.105320. Epub 2010 May 26.

Aminoacyl transfer rate dictates choice of editing pathway in threonyl-tRNA synthetase.

Author information

  • 1Cell and Molecular Biology Program, University of Vermont, Burlington, VT 05405, USA.

Abstract

Aminoacyl-tRNA synthetases hydrolyze aminoacyl adenylates and aminoacyl-tRNAs formed from near-cognate amino acids, thereby increasing translational fidelity. The contributions of pre- and post-transfer editing pathways to the fidelity of Escherichia coli threonyl-tRNA synthetase (ThrRS) were investigated by rapid kinetics. In the pre-steady state, asymmetric activation of cognate threonine and noncognate serine was observed in the active sites of dimeric ThrRS, with similar rates of activation. In the absence of tRNA, seryl-adenylate was hydrolyzed 29-fold faster by the ThrRS catalytic domain than threonyl-adenylate. The rate of seryl transfer to cognate tRNA was only 2-fold slower than threonine. Experiments comparing the rate of ATP consumption to the rate of aminoacyl-tRNA(AA) formation demonstrated that pre-transfer hydrolysis contributes to proofreading only when the rate of transfer is slowed significantly. Thus, the relative contributions of pre- and post-transfer editing in ThrRS are subject to modulation by the rate of aminoacyl transfer.

PMID:
20504770
[PubMed - indexed for MEDLINE]
PMCID:
PMC2911285
Free PMC Article

Images from this publication.See all images (4)Free text

FIGURE 1.
FIGURE 2.
FIGURE 3.
FIGURE 4.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk