PMID: 32869027

Authors:

Flower TG, Buffalo CZ, Hooy RM, Allaire M, Ren X, Hurley JH

Title:

Structure of SARS-CoV-2 ORF8, a rapidly evolving coronavirus protein implicated in immune evasion.

Journal:

bioRxiv. 2020 Aug 27. doi: 10.1101/2020.08.27.270637.

Abstract:

The molecular basis for the severity and rapid spread of the COVID-19 disease caused by SARS-CoV-2 is largely unknown. ORF8 is a rapidly evolving accessory protein that has been proposed to interfere with immune responses. The crystal structure of SARS-CoV-2 ORF8 was determined at 2.04 A resolution by x-ray crystallography. The structure reveals a ~60 residue core similar to SARS-CoV ORF7a with the addition of two dimerization interfaces unique to SARS-CoV-2 ORF8. A covalent disulfide-linked dimer is formed through an N-terminal sequence specific to SARS-CoV-2, while a separate non-covalent interface is formed by another SARS-CoV-2-specific sequence, 73 YIDI 76 . Together the presence of these interfaces shows how SARS-CoV-2 ORF8 can form unique large-scale assemblies not possible for SARS-CoV, potentially mediating unique immune suppression and evasion activities.