Expression, purification, and crystallization of glutamyl-tRNA Gln specific amidotransferase from Bacillus stearothermophilus

Joon Hyeok Kwak, Kunyoo Shin, Ji Su Woo, Mun Kyung Kim, Sung Il Kim, Soo Hyun Eom, Hong Kwang-Won

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Although the genes that encode the glutamyl-tRNAGln (Glu-tRNAGln) specific amidotransferase (Glu-AdTase) from various bacteria and eukaryotic organelles are known, the precise mechanism of the enzyme is still unclear. One of the reasons is that there is no information on the three-dimensional structure of the complex, the Glu-AdTase:Glu-tRNA Gln:ATP:amino group donor. To obtain the crystals of Glu-AdTase, the Glu-AdTase of Bacillus stearothermophilus was overexpressed and purified after cloning of the gene that encodes the enzyme. The cloned DNA contained the full-length gene cluster that represented the Glu-AdTase of B. stearothermophilus, and was organized as an operon that consisted of three open-reading frames (ORFs). The order of the genes was gatCAB, as shown in Bacillus subtilis. The ORFs showed a high amino-acid homology to those of B. subtilis (A subunit, 73.2%; B subunit, 81.6%; C subunit, 69.5%) and Staphylococcus aureus (A subunit, 61.9%; B subunit, 71.8%; C subunit, 45.9%). The ORFs were re-cloned on the overexpression vector, pTrc99a, and a recombinant pTrcgatCABBST was obtained. The Glu-AdTase that was overexpresscd with pTrcgatCABBST in Escherichia coli retained transamidation activity on the mischarged glutamic acid on the tRNAGln. It also produced correctly-charged Gln-tRNAGln at 37, 42, and 50°C. Although Glu-AdTases from both B. subtilis and B. stearothermophilus were subjected to crystallization, the micro-crystals were only obtained from the B. stearothermophilus enzyme.

Original languageEnglish (US)
Pages (from-to)374-381
Number of pages8
JournalMolecules and Cells
Issue number3
StatePublished - Dec 2002
Externally publishedYes


  • Bacillus stearothermophilus gatCAB
  • Glu-tRNA Amidotransferase (Glu-AdTase)
  • Purification and Crystallization

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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