Human angiotensin‑converting enzyme 2‑specific benzothiazole-based allosteric inhibitor against pan‑sarbecoviruses

Abstract

Emerging SARS‑CoV‑2 variants and related zoonotic sarbecoviruses rely on ACE2 for cell entry, motivating host‑directed antivirals that block spike-ACE2 interaction. Here, we characterize MB‑32, a benzothiazole small molecule that binds ACE2, selectively disrupts binding of SARS‑CoV‑2 spike receptor‑binding domain to ACE2, and preserves ACE2 enzymatic activity across species. MB‑32 potently inhibits entry of SARS‑CoV‑2 variants, SARS‑CoV‑1 and diverse bat/pangolin sarbecoviruses in ACE2‑expressing cells, while sparing vesicular stomatitis virus and authentic MERS‑CoV, indicating non‑virucidal, ACE2‑focused activity. Biochemical and biophysical analyses, supported by ACE2 mutagenesis, support a model in which MB‑32 engages a non‑catalytic surface pocket on the ACE2 N‑terminal helix to allosterically disrupt spike attachment. Intranasal MB‑32 achieves high airway concentrations, protects male ACE2‑transgenic mice and hamsters from SARS‑CoV‑2 disease, and prevents contact transmission of Omicron‑lineage viruses without detectable cardiovascular toxicity. These findings establish MB‑32 as a host‑targeted ACE2 entry inhibitor and provide a framework for small‑molecule ACE2‑directed antivirals against current and future sarbecovirus spillovers.