Design of Entry Inhibitor Peptides Covalently Bonding SARS-CoV-2 Variants in Wastewater

Design of inhibitors with universal blocking activities for variants of concern is highly demanded in fighting against the COVID-19 pandemic. We proposed an <i>in silico</i>-aided design of entry inhibitor peptides that block protein-protein interaction between SARS-CoV-2 receptor-binding domain (RBD) and human angiotensin-converting enzyme 2 (hACE2). First, we screened affinity peptides by identifying hot spot residues of hACE2 that interact with the prototype RBD. Then, equipped with sulfur(VI) fluoride exchange reaction modifications and added with a PEG12 spacer arm, the entry inhibitor peptides could form irreversible bonds with the RBD in a wide range, potentially overcoming the inhibition escape of SARS-CoV-2 variants with RBD mutations. Combined with magnetic beads, the entry inhibitor peptides were used as enrichment materials to preconcentrate SARS-CoV-2 pseudovirus in different water matrices, showing recoveries of 15-75% even in 10²-10⁷ copies/mL wastewater. The entry inhibitor peptides may serve as a starting point for the development of new viral capturing, enrichment, and detection technologies in the field of environmental monitoring.