Nat Commun . Cryo-EM Structures of HKU2 and SADS-CoV Spike Glycoproteins Provide Insights Into Coronavirus Evolution

[tetano]

Nat Commun


. 2020 Jun 17;11(1):3070.
doi: 10.1038/s41467-020-16876-4.
Cryo-EM Structures of HKU2 and SADS-CoV Spike Glycoproteins Provide Insights Into Coronavirus Evolution


Jinfang Yu ¹ , Shuyuan Qiao ¹ , Runyu Guo ¹ , Xinquan Wang ²



Affiliations

• PMID: 32555182
• DOI: 10.1038/s41467-020-16876-4

Abstract

Porcine coronavirus SADS-CoV has been identified from suckling piglets with severe diarrhea in southern China in 2017. The SADS-CoV genome shares ~95% identity to that of bat α-coronavirus HKU2, suggesting that SADS-CoV may have emerged from a natural reservoir in bats. Here we report the cryo-EM structures of HKU2 and SADS-CoV spike (S) glycoprotein trimers at 2.38 ? and 2.83 ? resolution, respectively. We systematically compare the domains of HKU2 spike with those of α-, β-, γ-, and δ-coronavirus spikes, showing that the S1 subunit N- and C-terminal domains of HKU2/SADS-CoV are ancestral domains in the evolution of coronavirus spike proteins. The connecting region after the fusion peptide in the S2 subunit of HKU2/SADS-CoV adopts a unique conformation. These results structurally demonstrate a close evolutionary relationship between HKU2/SADS-CoV and β-coronavirus spikes and provide insights into the evolution and cross-species transmission of coronaviruses.