3PZ0: The Crystal Structure Of Aaleurs-cp1

A large insertion domain called CP1 (connective peptide 1) present in class Ia aminoacyl-tRNA synthetases is responsible for post-transfer editing. LeuRS (leucyl-tRNA synthetase) from Aquifex aeolicus and Giardia lamblia possess unique 20 and 59 amino acid insertions respectively within the CP1 that are crucial for editing activity. Crystal structures of AaLeuRS-CP1 [2.4 A (1 A=0.1 nm)], GlLeuRS-CP1 (2.6 A) and the insertion deletion mutant AaLeuRS-CP1Delta20 (2.5 A) were solved to understand the role of these insertions in editing. Both insertions are folded as peripheral motifs located on the opposite side of the proteins from the active-site entrance in the CP1 domain. Docking modelling and site-directed mutagenesis showed that the insertions do not interact with the substrates. Results of molecular dynamics simulations show that the intact CP1 is more dynamic than its mutant devoid of the insertion motif. Taken together, the data show that a peripheral insertion without a substrate-binding site or major structural role in the active site may modulate catalytic function of a protein, probably from protein dynamics regulation in two respective LeuRS CP1s. Further results from proline and glycine mutational analyses intended to reduce or increase protein flexibility are consistent with this hypothesis.
PDB ID: 3PZ0Download
MMDB ID: 92883
PDB Deposition Date: 2010/12/13
Updated in MMDB: 2011/08
Experimental Method:
x-ray diffraction
Resolution: 2.4  Å
Source Organism:
Similar Structures:
Biological Unit for 3PZ0: monomeric; determined by author and by software (PISA)
Molecular Components in 3PZ0
Label Count Molecule
Protein (1 molecule)
Leucyl-trna Synthetase Subunit Alpha(Gene symbol: leuS)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB