Plasmodium Apicoplast Gln-tRNAGln Biosynthesis Utilizes a Unique GatAB Amidotransferase Essential for Erythrocytic Stage Parasites

J Biol Chem. 2015 Dec 4;290(49):29629-41. doi: 10.1074/jbc.M115.655100. Epub 2015 Aug 28.


The malaria parasite Plasmodium falciparum apicoplast indirect aminoacylation pathway utilizes a non-discriminating glutamyl-tRNA synthetase to synthesize Glu-tRNA(Gln) and a glutaminyl-tRNA amidotransferase to convert Glu-tRNA(Gln) to Gln-tRNA(Gln). Here, we show that Plasmodium falciparum and other apicomplexans possess a unique heterodimeric glutamyl-tRNA amidotransferase consisting of GatA and GatB subunits (GatAB). We localized the P. falciparum GatA and GatB subunits to the apicoplast in blood stage parasites and demonstrated that recombinant GatAB converts Glu-tRNA(Gln) to Gln-tRNA(Gln) in vitro. We demonstrate that the apicoplast GatAB-catalyzed reaction is essential to the parasite blood stages because we could not delete the Plasmodium berghei gene encoding GatA in blood stage parasites in vivo. A phylogenetic analysis placed the split between Plasmodium GatB, archaeal GatE, and bacterial GatB prior to the phylogenetic divide between bacteria and archaea. Moreover, Plasmodium GatA also appears to have emerged prior to the bacterial-archaeal phylogenetic divide. Thus, although GatAB is found in Plasmodium, it emerged prior to the phylogenetic separation of archaea and bacteria.

Keywords: apicoplast; glutamyl-tRNA amidotransferase; glutamyl-tRNA synthetase; malaria; nucleic acid; nucleic acid enzymology; plasmodium; transfer RNA (tRNA).

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antimalarials / chemistry
  • Apicoplasts / metabolism*
  • Cell Nucleus / metabolism
  • Computational Biology
  • Erythrocytes / parasitology
  • GATA Transcription Factors / metabolism*
  • Gene Deletion
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Malaria / metabolism
  • Malaria / parasitology
  • Models, Molecular
  • Nitrogenous Group Transferases / metabolism*
  • Phylogeny
  • Plasmodium falciparum / metabolism*
  • Protein Structure, Tertiary
  • Protozoan Proteins / metabolism*
  • RNA, Transfer, Amino Acyl / biosynthesis*
  • RNA, Transfer, Gln / genetics
  • Recombinant Proteins / metabolism


  • Antimalarials
  • GATA Transcription Factors
  • Protozoan Proteins
  • RNA, Transfer, Amino Acyl
  • RNA, Transfer, Gln
  • Recombinant Proteins
  • glutamyl-tRNA(Gln)
  • Green Fluorescent Proteins
  • Nitrogenous Group Transferases

Associated data

  • PDB/2df4
  • PDB/2f2a
  • PDB/2g5i