Table 1.
Significance of the nonstructural proteins in virus replication cycle and host pathogenesis
| Protein | Role in virus life cycle | Role in host pathogenesis |
|---|---|---|
| nsp1 | Inhibits host protein translation by the interaction with 40S ribosomal subunit and host mRNA | |
| nsp2 | Disturbs cell cycle by binding to prohibitin 1 and prohibitin 2 proteins | |
| nsp3 (PLpro) | Protease, ssRNA binding | Interacts with host RNA G‐quadruplex to inhibit host translation, suppresses host innate immune responses by deubiquitination, deISGylation, and ADPr binding |
| nsp4 | Assembling the viral double‐membrane vesicles | |
| nsp5 (Mpro/3CLpro) | Protease | |
| nsp6 | Induction of autophagosomes | |
| nsp7 | Primer synthesis and RNA replication | |
| nsp8 | Primer synthesis and RNA replication | |
| nsp9 | Putative role as ssRNA binding | Interacts with DEAD‐box RNA helicase 5 (DDX5) cellular protein to facilitate virus replication |
| nsp10 | mRNA cap methylation | |
| nsp12 (RdRp) | RNA replication, mRNA capping | |
| nsp13 (Helicase) | Helicase activity during RNA replication, 5ʹ‐triphosphatase activity for mRNA capping | |
| nsp14 (ExoN) | Proof reading during RNA synthesis, N7‐methyltransferase during mRNA capping | |
| nsp15 (NendoU) | Endoribonuclease cleaves RNA at polyuridylate sites | |
| nsp16 | 2ʹ‐O‐ribose methyltransferase during mRNA capping |
Note: Information is based on SARS‐CoV‐2 nsps or identical nsps from other previously studied coronaviruses.
Abbreviations: mRNA, messenger RNA; ssRNA, single‐stranded RNA.
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