**4.2 Virus genome replication**

Generally, the virus replication directly affects the viral burden and symptom severity in viral infections. Therefore, targeting the key molecules in the *SARS-CoV-2* replication has been highly regarded for drug discovery against COVID-19. Previous studies confirmed that 3-chymotrypsin-like cysteine protease (3CLpro), papain-like protease (PLpro), RNA-dependent RNA polymerase (RdRp), and NSPs involved in the formation of double-membrane vesicles (DMVs) are vital for the replication of *SARS-CoV-2* [28]. Among the mentioned proteins, the 3CLpro is highly regarded as an attractive target for drug development against *SARS-CoV-2* because of its key role in the viral life cycle alongside the absence of closely related homologs in humans. Subsequently, to date, several


**Table 2.**

*List of some neutralizing monoclonal antibodies against SARS-CoV-2 S1.*

*Evaluation of Drug Repositioning by Molecular Docking of Pharmaceutical Resources… DOI: http://dx.doi.org/10.5772/intechopen.101395*

efforts have been made to identify the effective *SARS-CoV-2* 3CLpro inhibitors. The 3CLpro inhibitors are mostly categorized into peptidic and small molecules. Up to now, the efficacies of several 3CLpro peptide inhibitors such as N3, 13b, GC373, and GC376 have been validated. Moreover, some small molecules such as disulfiram, carmofur, ebselen, and tideglusib are known to inhibit 3CLpro from *SARS-CoV-2* [27, 29].
