1TKE: Crystal Structure Of The Editing Domain Of Threonyl-trna Synthetase Complexed With Serine

The fidelity of aminoacylation of tRNA(Thr) by the threonyl-tRNA synthetase (ThrRS) requires the discrimination of the cognate substrate threonine from the noncognate serine. Misacylation by serine is corrected in a proofreading or editing step. An editing site has been located 39 A away from the aminoacylation site. We report the crystal structures of this editing domain in its apo form and in complex with the serine product, and with two nonhydrolyzable analogs of potential substrates: the terminal tRNA adenosine charged with serine, and seryl adenylate. The structures show how serine is recognized, and threonine rejected, and provide the structural basis for the editing mechanism, a water-mediated hydrolysis of the mischarged tRNA. When the adenylate analog binds in the editing site, a phosphate oxygen takes the place of one of the catalytic water molecules, thereby blocking the reaction. This rules out a correction mechanism that would occur before the binding of the amino acid on the tRNA.
PDB ID: 1TKEDownload
MMDB ID: 30318
PDB Deposition Date: 2004/6/8
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.46  Å
Source Organism:
Similar Structures:
Biological Unit for 1TKE: monomeric; determined by author and by software (PISA)
Molecular Components in 1TKE
Label Count Molecule
Protein (1 molecule)
Threonyl-trna Synthetase(Gene symbol: thrS)
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB