1WNU: Structure Of Archaeal Trans-Editing Protein Alax In Complex With L- Serine

AlaX is the homologue of the class II alanyl-tRNA synthetase editing domain and has been shown to exhibit autonomous editing activity against mischarged tRNA(Ala). Here, we present the structures of AlaX from the archaeon Pyrococcus horikoshii in apo form, complexed with zinc, and with noncognate amino acid l-serine and zinc. Together with mutational analysis, we demonstrated that the conserved Thr-30 hydroxyl group located near the beta-methylene of the bound serine is responsible for the discrimination of noncognate serine from cognate alanine, based on their chemical natures. Furthermore, we confirmed that the conserved Gln-584 in alanyl-tRNA synthetase, which corresponds to Thr-30 of AlaX, is also critical for discrimination. These observations strongly suggested conservation of the chemical discrimination among trans- and cis-editing of tRNA(Ala).
PDB ID: 1WNUDownload
MMDB ID: 34138
PDB Deposition Date: 2004/8/9
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 2.8  Å
Source Organism:
Similar Structures:
Biological Unit for 1WNU: dimeric; determined by author
Molecular Components in 1WNU
Label Count Molecule
Proteins (2 molecules)
Alanyl-trna Synthetase(Gene symbol: PH_RS02685)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB