Role of structural and functional proteins of SARS -COV-2

Severe acute respiratory corona virus-2 (SARS-CoV-2) is a ribonucleic acid (RNA) virus with enveloped no-segmented positive sense belonging to a beta (β) - corona virus family. It has 29,903 nucleotides sized genome with 10 open reading frames (ORF). ORF1 (ab) encodes two polypeptides pp1a and pp1b cleaved into 16 functional proteins, which are mainly intended to form replication transcription complex (RTC). The cleavage process of pp1a and pp1b polypeptides to 16 functional proteins of SARs-CoV-2 is mainly facilitated by main protease and papain-like protease. The replication transcription complex (RTC) formed by the action of 16-functional proteins of SARs-CoV-2 is mainly involved as viral RNA synthesis machinery in the transcriptional and replication process of viral RNAs. ORF (2-10) encodes for structural (for example: spike (S), membrane (M), nucleocapsid (N), and envelop (E)) and accessory proteins of SARs-CoV-2. The main functions of structural proteins are viral assembly, viral coating, viral entry into host cells and assembly of the RNA genome. Accessory proteins are proteins that are not involved in the viral synthesis machinery, as 16 functional proteins, and in the viral assembly, coating, entry into host cells and packaging of Viral RNAs, as structural proteins. Rather, these are proteins that may play central role by enhancing viral assembly process, virulence and pathogenesis of SARs-CoV-2. Our aim in the current review was to elaborate the specific role of these structural and functional proteins on viral genomic replication and transcription, viral assembly, host cell attachment and pathogenesis. Multiple literatures have been reviewed to achieve the objective of this review.