Structural basis of increased binding affinities of spikes from SARS-CoV-2 Omicron variants to rabbit and hare ACE2s reveals the expanding host tendency.

The potential host range of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been expanding alongside its evolution during the pandemic, with rabbits and hares being considered important potential hosts, supported by a report of rabbit sero-prevalence in nature. We measured the binding affinities of rabbit and hare angiotensin-converting enzyme 2 (ACE2) with receptor-binding domains (RBDs) from SARS-CoV, SARS-CoV-2, and its variants and found that rabbit and hare ACE2s had broad variant tropism, with significantly enhanced affinities to Omicron BA.4/5 and its subsequent-emerged sub-variants (>10 fold).

Broader-species receptor binding and structural bases of Omicron SARS-CoV-2 to both mouse and palm-civet ACE2s.

The Omicron variant of SARS-CoV-2 carries multiple unusual mutations, particularly in the receptor-binding domain (RBD) of the spike (S) protein. Moreover, host-adapting mutations, such as residues 493, 498, and 501, were also observed in the Omicron RBD, which indicates that it is necessary to evaluate the interspecies transmission risk of the Omicron variant. Herein, we evaluated the interspecies recognition of the Omicron BA.

Receptor binding and complex structures of human ACE2 to spike RBD from omicron and delta SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) pandemic continues worldwide with many variants arising, some of which are variants of concern (VOCs). A recent VOC, omicron (B.1.