Inhibitory mechanism of reveromycin A at the tRNA binding site of a class I synthetase.

Chen, Bingyi; Luo, Siting; Zhang, Songxuan; Ju, Yingchen; Gu, Qiong; Xu, Jun; Yang, Xiang-Lei; Zhou, Huihao · Nat Commun · 2021

basic_science · Level V

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Abstract

The polyketide natural product reveromycin A (RM-A) exhibits antifungal, anticancer, anti-bone metastasis, anti-periodontitis and anti-osteoporosis activities by selectively inhibiting eukaryotic cytoplasmic isoleucyl-tRNA synthetase (IleRS). Herein, a co-crystal structure suggests that the RM-A molecule occupies the substrate tRNA<sup>Ile</sup> binding site of Saccharomyces cerevisiae IleRS (ScIleRS), by partially mimicking the binding of tRNA<sup>Ile</sup>. RM-A binding is facilitated by the copurified intermediate product isoleucyl-adenylate (Ile-AMP). The binding assays confirm that RM-A competes with tRNA<sup>Ile</sup> while binding synergistically with L-isoleucine or intermediate analogue Ile-AMS to the aminoacylation pocket of ScIleRS. This study highlights that the vast tRNA binding site of the Rossmann-fold catalytic domain of class I aminoacyl-tRNA synthetases could be targeted by a small molecule. This finding will inform future rational drug design.

Medical subject headings