Fig. 2.

Schematic diagram of SARS-CoV-2 life cycle and potential antiviral drug targets based on life cycle. SARS-CoV-2 life cycle comprises several stages. 1) Attachment of the viral S glycoprotein RBM with cellular receptor ACE2 to facilitate entry into the host cell. 2) Disassembly of SARS-CoV-2 to release the RNA into the cytoplasm of the host cell. 3) The viral RNA is translated into replicase polyproteins, which are further cleaved by the viral proteases, papain like protease (PL^pro) and 3C like protease (3CL^pro) to produce non-structural proteins (nsps). 4) The viral RNA also acts as a template for synthesis of negative sense RNA which subsequently converts to positive sense genomic RNAs. 5) RdRp, one of the nsps, get involved in non-contiguous transcription to produce subgenomic RNAs which are consequently translated into the viral structural proteins. 6) The RNA genome and structural proteins assemble to form new virions. 7) Subsequently mature virions are released from the host cell. Bar-headed lines and red fonts indicate potential antiviral drug targets-viral spike protein/host cellular receptors, protease inhibitors, RdRp inhibitors, and mRNA synthesis inhibitors-that can block different stages of viral life cycle.