Crystal structure of threonyl-tRNA synthetase (ThrRS) from Salmonella enterica in complex with an inhibitorCrystal structure of threonyl-tRNA synthetase (ThrRS) from Salmonella enterica in complex with an inhibitor

Structural highlights

7cbh is a 2 chain structure with sequence from Salmonella enterica subsp. enterica serovar Cubana str. 76814. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.95Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

V7II86_SALET

Publication Abstract from PubMed

Aminoacyl-tRNA synthetases (aaRSs) are an attractive class of antibacterial drug targets due to their essential roles in protein translation. While most traditional aaRS inhibitors target the binding pockets of substrate amino acids and/or ATP, we recently developed a class of novel tRNA-amino acid dual-site inhibitors including inhibitor 3 ((2S,3R)-2-amino-N-((E)-4-(6,7-dichloro-4-oxoquinazolin-3(4H)-yl)but-2-en-1-yl)-3 -hydroxybutanamide) against threonyl-tRNA synthetase (ThrRS). Here, the binding modes and structure-activity relationships (SARs) of these inhibitors were analyzed by the crystal structures of Salmonella enterica ThrRS (SeThrRS) in complex with three of them. Based on the cocrystal structures, twelve quinazolinone-threonine hybrids were designed and synthesized, and their affinities, enzymatic inhibitory activities, and cellular potencies were evaluated. The best derivative 8g achieved a Kd value of 0.40 muM, an IC50 value of 0.50 muM against SeThrRS and MIC values of 16-32 mug/mL against the tested bacterial strains. The cocrystal structure of the SeThrRS-8g complex revealed that 8g induced a bended conformation for Met332 by forming hydrophobic interactions, which better mimicked the binding of tRNA(Thr) to ThrRS. Moreover, the inhibitory potency of 8g was less impaired than a reported ATP competitive inhibitor at high concentrations of ATP, supporting our hypothesis that tRNA site inhibitors are likely superior to ATP site inhibitors in vivo, where ATP typically reaches millimolar concentrations.

Structure-guided optimization and mechanistic study of a class of quinazolinone-threonine hybrids as antibacterial ThrRS inhibitors.,Guo J, Chen B, Yu Y, Cheng B, Ju Y, Tang J, Cai Z, Gu Q, Xu J, Zhou H Eur J Med Chem. 2020 Sep 19;207:112848. doi: 10.1016/j.ejmech.2020.112848. PMID:32980741[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Guo J, Chen B, Yu Y, Cheng B, Ju Y, Tang J, Cai Z, Gu Q, Xu J, Zhou H. Structure-guided optimization and mechanistic study of a class of quinazolinone-threonine hybrids as antibacterial ThrRS inhibitors. Eur J Med Chem. 2020 Dec 1;207:112848. PMID:32980741 doi:10.1016/j.ejmech.2020.112848

7cbh, resolution 1.95Å

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