Allosteric inhibition of tRNA synthetase Gln4 by N-pyrimidinyl-β-thiophenylacrylamides exerts highly selective antifungal activity

• Published in: Cell chemical biology Vol. 31; no. 4; pp. 760 - 775.e17
• Main Authors: Puumala, Emily, Sychantha, David, Lach, Elizabeth, Reeves, Shawn, Nabeela, Sunna, Fogal, Meea, Nigam, AkshatKumar, Johnson, Jarrod W., Aspuru-Guzik, Alán, Shapiro, Rebecca S., Uppuluri, Priya, Kalyaanamoorthy, Subha, Magolan, Jakob, Whitesell, Luke, Robbins, Nicole, Wright, Gerard D., Cowen, Leah E.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 18.04.2024
• Subjects: antifungal; Candida; fungal pathogens; Gln4; glutaminyl-tRNA synthetase; translation inhibitor; antifungal; Gln4; glutaminyl-tRNA synthetase; translation inhibitor; fungal pathogens; Candida
• ISSN: 2451-9456; 2451-9456
• DOI: 10.1016/j.chembiol.2024.01.010

Candida species are among the most prevalent causes of systemic fungal infections, which account for ∼1.5 million annual fatalities. Here, we build on a compound screen that identified the molecule N-pyrimidinyl-β-thiophenylacrylamide (NP-BTA), which strongly inhibits Candida albicans growth. NP-BTA was hypothesized to target C. albicans glutaminyl-tRNA synthetase, Gln4. Here, we confirmed through in vitro amino-acylation assays NP-BTA is a potent inhibitor of Gln4, and we defined how NP-BTA arrests Gln4’s transferase activity using co-crystallography. This analysis also uncovered Met496 as a critical residue for the compound’s species-selective target engagement and potency. Structure-activity relationship (SAR) studies demonstrated the NP-BTA scaffold is subject to oxidative and non-oxidative metabolism, making it unsuitable for systemic administration. In a mouse dermatomycosis model, however, topical application of the compound provided significant therapeutic benefit. This work expands the repertoire of antifungal protein synthesis target mechanisms and provides a path to develop Gln4 inhibitors. [Display omitted] •NP-BTA allosterically inhibits the C. albicans glutaminyl-tRNA synthetase Gln4•Met496 is a critical residue for the compound’s species-selective target engagement•Topical application of NP-BTA provided benefit in a mouse dermatomycosis model•Fungal protein synthesis is a promising target for future antifungal development Fungal pathogens pose a threat to human health. Puumala et al. demonstrate that the compound NP-BTA inhibits the Candida albicans glutaminyl-tRNA synthetase by locking the allosteric site in a non-productive state. In a mouse dermatomycosis model, application of NP-BTA provided therapeutic benefit, supporting translation inhibition as a promising antifungal strategy.