Aminoacyl-tRNA synthetases (aaRSs) covalently attach an amino acid to its cognate tRNA isoacceptors through an ester bond. The standard set of 20 amino acids implies 20 aaRSs for each pair of amino acid/tRNA isoacceptors. However, the genomes of all archaea and some bacteria do not encode for a complete set of 20 aaRSs. For the human pathogenic bacterium Helicobacter pylori, a gene encoding asparaginyl-tRNA synthetase (AsnRS) is absent whilst an aspartyl-tRNA synthetase (AspRS) aminoacylates both tRNA(Asp) and tRNA(Asn) with aspartate. The structural and functional basis for this non-discriminatory behavior is not well understood. Here we report the over-production of the N-terminal anticodon-binding domain of H. pylori ND-AspRS using Escherichia coli BL21(DE3) host cells. Prolonged expression of this protein resulted in a toxic phenotype, limiting the expression period to just 30min. Purified protein was monomeric in solution by gel filtration chromatography and stable up to 42°C as observed in temperature-dependent dynamic light scattering measurements. Circular dichroism indicated a mixture of α-helix and β-sheet secondary structure at 20°C and predominantly β-sheet at 70°C. Optimized crystallization conditions at pH 5.6 with PEG 4000 as a co-precipitant produced well-formed crystals and (1)H NMR spectrum showed a well dispersed chemical shift envelope characteristic of a folded protein.
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http://dx.doi.org/10.1016/j.pep.2013.02.006 | DOI Listing |
J Biol Chem
August 2020
Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA. Electronic address:
Human lysyl-tRNA synthetase (hLysRS) is essential for aminoacylation of tRNA Higher eukaryotic LysRSs possess an N-terminal extension (Nterm) previously shown to facilitate high-affinity tRNA binding and aminoacylation. This eukaryote-specific appended domain also plays a critical role in hLysRS nuclear localization, thus facilitating noncanonical functions of hLysRS. The structure is intrinsically disordered and therefore remains poorly characterized.
View Article and Find Full Text PDFBiochem Biophys Res Commun
April 2019
Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan. Electronic address:
This study reports the X-ray crystallographic structure of the glycyl-tRNA synthetase (GlyRS) of Nanoarchaeum equitans - a hyperthermophilic archaeal species. This is the first archaeal GlyRS crystal structure elucidated. The GlyRS comprises an N-terminal catalytic domain and a C-terminal anticodon-binding domain with a long β-sheet inserted between these domains.
View Article and Find Full Text PDFBiochem J
November 2018
Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
The asparaginyl-tRNA synthetase (NRS) catalyzes the attachment of asparagine to its cognate tRNA during translation. NRS first catalyzes the binding of Asn and ATP to form the NRS-asparaginyl adenylate complex, followed by the esterification of Asn to its tRNA. We investigated the role of constituent domains in regulating the structure and activity of NRS (FgNRS).
View Article and Find Full Text PDFActa Crystallogr F Struct Biol Commun
February 2017
Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, and Special Research Unit for Advanced Magnetic Resonance, Kasetsart University, 50 Ngamwongwan Road, Chatuchak, Bangkok 10900, Thailand.
The N-terminal anticodon-binding domain of the nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) plays a crucial role in the recognition of both tRNA and tRNA. Here, the first X-ray crystal structure of the N-terminal domain of this enzyme (ND-AspRS) from the human-pathogenic bacterium Helicobacter pylori is reported at 2.0 Å resolution.
View Article and Find Full Text PDFJ Biol Chem
May 2016
From the Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712 and
The mitochondrial tyrosyl-tRNA synthetases (mtTyrRSs) of Pezizomycotina fungi, a subphylum that includes many pathogenic species, are bifunctional proteins that both charge mitochondrial tRNA(Tyr) and act as splicing cofactors for autocatalytic group I introns. Previous studies showed that one of these proteins, Neurospora crassa CYT-18, binds group I introns by using both its N-terminal catalytic and C-terminal anticodon binding domains and that the catalytic domain uses a newly evolved group I intron binding surface that includes an N-terminal extension and two small insertions (insertions 1 and 2) with distinctive features not found in non-splicing mtTyrRSs. To explore how this RNA binding surface diverged to accommodate different group I introns in other Pezizomycotina fungi, we determined x-ray crystal structures of C-terminally truncated Aspergillus nidulans and Coccidioides posadasii mtTyrRSs.
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