Cryo-EM structures of HKU2 and SADS-CoV spike glycoproteins provide insights into coronavirus evolution.

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 ?-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?Å and 2.83?Å resolution, respectively. We systematically compare the domains of HKU2 spike with those of ?-, ?-, ?-, and ?-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 ?-coronavirus spikes and provide insights into the evolution and cross-species transmission of coronaviruses.

SUBMITTER: Yu J 

PROVIDER: S-EPMC7300015 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature