An appended domain results in an unusual architecture for malaria parasite tryptophanyl-tRNA synthetase

PLoS One. 2013 Jun 12;8(6):e66224. doi: 10.1371/journal.pone.0066224. Print 2013.

Abstract

Specific activation of amino acids by aminoacyl-tRNA synthetases (aaRSs) is essential for maintaining fidelity during protein translation. Here, we present crystal structure of malaria parasite Plasmodium falciparum tryptophanyl-tRNA synthetase (Pf-WRS) catalytic domain (AAD) at 2.6 Å resolution in complex with L-tryptophan. Confocal microscopy-based localization data suggest cytoplasmic residency of this protein. Pf-WRS has an unusual N-terminal extension of AlaX-like domain (AXD) along with linker regions which together seem vital for enzymatic activity and tRNA binding. Pf-WRS is not proteolytically processed in the parasites and therefore AXD likely provides tRNA binding capability rather than editing activity. The N-terminal domain containing AXD and linker region is monomeric and would result in an unusual overall architecture for Pf-WRS where the dimeric catalytic domains have monomeric AXDs on either side. Our PDB-wide comparative analyses of 47 WRS crystal structures also provide new mechanistic insights into this enzyme family in context conserved KMSKS loop conformations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, Ion Exchange
  • Cloning, Molecular
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli
  • Fluorescent Antibody Technique
  • Microscopy, Confocal
  • Models, Molecular*
  • Plasmodium falciparum / enzymology*
  • Protein Binding
  • Protein Conformation*
  • Tryptophan / chemistry*
  • Tryptophan-tRNA Ligase / chemistry*

Substances

  • Tryptophan
  • Tryptophan-tRNA Ligase

Associated data

  • PDB/4JFA

Grants and funding

The funding agency for this work is the Department of Biotechnology, Govt. of India. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.