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Signatures of tRNA Glx -specificity in bacterial glutamyl-tRNA synthetases
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  • Gautam Basu,
  • Saumya Dasgupta,
  • Aditya Dev,
  • Nipa Chongdar
Gautam Basu
Bose Institute Department of Biophysics

Corresponding Author:[email protected]

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Saumya Dasgupta
Bose Institute Department of Biophysics
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Aditya Dev
Bose Institute Department of Biophysics
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Nipa Chongdar
Bose Institute Department of Biophysics
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The canonical function of glutamyl-tRNA synthetase (GluRS) is to glutamylate tRNA Glu. Yet, not all bacterial GluRSs glutamylate tRNA Glu; many glutamylate both tRNA Glu and tRNA Gln, while some glutamylate only tRNA Gln and not the cognate substrate tRNA Glu. Understanding the basis of this unique tRNA Glx-specificity is important. Mutational studies have hinted at hotspot residues, both on tRNA Glx and GluRS, that play crucial roles in tRNA Glx-specificity. But the underlying structural basis remains unexplored. Majority of biochemical studies related to tRNA Glx-specificity have been performed on GluRS from Escherichia coli and other proteobacterial species. However, since the early crystal structures of GluRS and tRNA Glu-bound GluRS were from non-proteobacterial species ( Thermus thermophilus), the proteobacterial biochemical data have often been interpreted in the context of non-proteobacterial GluRS structures. Marked differences between proteo- and non-proteobacterial GluRSs have been demonstrated and therefore it is important that tRNA Glx-specificity be understood vis-a-vis proteobacterial GluRS structures. Towards this goal we have solved the crystal structure of GluRS from E. coli. Using the solved structure and several other currently available proteo- and non-proteobacterial GluRS crystal structures, we have probed the structural basis of tRNA Glx-specificity of bacterial GluRSs. Specifically, our analysis suggests a unique role played by a tRNA Glx D-helix contacting loop of GluRS in modulation of tRNA Gln-specificity. While earlier studies had identified functional hotspots on tRNA Glx that controlled tRNA Glx-specificity of GluRS, this is the first report of complementary signatures of tRNA Glx-specificity in GluRS.
21 Jun 2023Submitted to PROTEINS: Structure, Function, and Bioinformatics
21 Jun 2023Submission Checks Completed
21 Jun 2023Assigned to Editor
21 Jun 2023Review(s) Completed, Editorial Evaluation Pending
27 Jun 2023Reviewer(s) Assigned
11 Aug 2023Editorial Decision: Revise Major
11 Aug 20231st Revision Received
12 Aug 2023Submission Checks Completed
12 Aug 2023Assigned to Editor
12 Aug 2023Review(s) Completed, Editorial Evaluation Pending
12 Aug 2023Reviewer(s) Assigned
19 Oct 2023Reviewer(s) Assigned
25 Oct 2023Editorial Decision: Accept