Potent Inhibition of SARS-CoV-2 nsp14 N7-Methyltransferase by Sulfonamide-Based Bisubstrate Analogues

Abstract

Enzymes involved in RNA capping of SARS-CoV-2 are essential for the stability of viral RNA, translation of mRNAs, and virus evasion from innate immunity, making them attractive targets for antiviral agents. In this work, we focused on the design and synthesis of nucleoside-derived inhibitors against the SARS-CoV-2 nsp14 ( N 7-guanine)-methyltransferase ( N 7-MTase) that catalyzes the transfer of the methyl group from the S -adenosyl- l -methionine (SAM) cofactor to the N 7-guanosine cap. Seven compounds out of 39 SAM analogues showed remarkable double-digit nanomolar inhibitory activity against the N 7-MTase nsp14. Molecular docking supported the structure–activity relationships of these inhibitors and a bisubstrate-based mechanism of action. The three most potent inhibitors significantly stabilized nsp14 (Δ T m ≈ 11 °C), and the best inhibitor demonstrated high selectivity for nsp14 over human RNA N 7-MTase.

Facile access to 4′-(N-acylsulfonamide) modified nucleosides and evaluation of their inhibitory activity against SARS-CoV-2 RNA cap N7-guanine-methyltransferase nsp14

“…[17][18][19] Recently, our group reported the synthesis of 5′-N-sulfonamide adenosine derivatives that showed significant inhibition of SARS-CoV-2 (N7-guanine)-methyltransferase (N7-MTase) nsp14 by acting as a competitor of S-adenosyl-L-methionine (SAM), the methyl donor in the N7-cap RNA methylation. 20 Interestingly, out of 39 synthesized compounds, 20 diversely substituted arylsulfonamide adenosines were shown to inhibit the enzyme nsp14 in the submicromolar range (Fig. 1B).…”

“…Sinefugin was used as positive control for its wellknown ability to inhibit MTases. 37 The inhibition data were 20 (C) Previous approaches for the synthesis of 4'-(N-acylsulfonamide) adenosine derivatives. 29,30 (D) This work describing an easy and efficient access to the target compounds via the sulfo-click reaction.…”

“…1 (A) Examples of bioactive compounds comprising an N-acylsulfonamide moiety. (B) Sulfonamide inhibitors of SARS-CoV-2 N7-MTase nsp14 previously reported 20. (C) Previous approaches for the synthesis of 4'-(N-acylsulfonamide) adenosine derivatives 29,30.…”

Bisubstrate Inhibitors of Severe Acute Respiratory Syndrome Coronavirus-2 Nsp14 Methyltransferase

“…During the preparation of this manuscript, potent and selective bisubstrate inhibitors that contained an sulfonamide functionality were reported; however, no antiviral activity was disclosed. 24 …”

The structure of monkeypox virus 2’-O-ribose methyltransferase VP39 in complex with sinefungin provides the foundation for inhibitor design

“…In fact, only a handful of inhibitors of viral MTases, mostly targeting flaviviruses 24,25 , were known prior to the COVID-19 pandemic. However, recently many inhibitors of SARS-CoV-2 MTases were reported by us and others [26][27][28][29][30] .…”