ACE2 N -glycosylation modulates interactions with SARS-CoV-2 spike protein in a site-specific manner

SARS-CoV-2 has evolved continuously and accumulated spike mutations with each variant having a different binding for the cellular ACE2 receptor. It is not known whether the interactions between such mutated spikes and ACE2 glycans are conserved among different variant lineages. Here, we focused on three ACE2 glycosylation sites (53, 90 and 322) that are geometrically close to spike binding sites and investigated the effect of their glycosylation pattern on spike affinity. These glycosylation deletions caused distinct site-specific changes in interactions with the spike and acted cooperatively. Of note, the particular interaction profiles were conserved between the SARS-CoV-2 parental virus and the variants of concern (VOCs) Delta and Omicron. Our study provides insights for a better understanding of the importance of ACE2 glycosylation on ACE2/SARS-CoV-2 spike interaction and guidance for further optimization of soluble ACE2 for therapeutic use.