The genome of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has two large open reading frames (ORFs): ORF1a and ORF1ab[1]. At the 5' end of genome encode polyproteins that are processed into 16 nonstructural proteins (nsp1-nsp16) by proteolytic enzymes, the Mpro (3CLpro) and the papain-like protease PLpro[2]. The accessory proteins and four structural proteins including: spike (S), membrane (M), envelope (E), and nucleocapsid (N) are encoded by the 3' end of the SARS-CoV-2 genome[3]. The genome of SARS-CoV-2 is similar to SARS-CoV except for the 3' open reading frame: SARS-CoV encodes ORF8a and ORF8b however ORF8 of the novel coronavirus is intact[4].
Relation between ORF8a and the mitochondrial protein TOM70 in SARS‐CoV‐2 infection