**5. Phosphorylation**

In SARS-CoV2 the most abundant genomic protein encoded is the N protein with a significantly higher level of translation at the early stage of the infection. In *Post-Translational Modifications of Proteins Exacerbate Severe Acute Respiratory Syndrome… DOI: http://dx.doi.org/10.5772/intechopen.100740*

all form of the coronaviruses, the N-protein is almost the same and conserved containing two globular domains, the N- terminal domain (NTD) and the C-terminal domain (CTD). Around these domains, intrinsically disorganized regions are present. N protein is dimeric with multiple RNA binding sites including one major RNA-binding groove, which is created by the two CTD piling on each other on NTD [42]. In previously published literature it has been found that in the disorganized region, there is an abundance of serine-arginine residues that is essential for the essential function and regulation of the N-protein [42]. Cytoplasmic kinases mediate the phosphorylation of the N-protein in the early infection phase. N protein, a helical nucleocapsid, constituent of SARS-CoV2 virus arranged in beads on a string pattern which shows binding with the RNA. It has two domains namely the N-terminal domain and C-terminal domain. It has been found that both domains contribute to the binding of the viral genome. In one of the recently published study, it was demonstrated in truncation analysis that an L/Q-rich region placed within the intrinsically disordered region of the SARS-CoV-2 N protein plays a vital role in RNA-mediated phase separation, which is located adjacent to the phosphorylated SR-rich region (constituting residues 176–206) [43]. In the same study, it was concluded that N protein central intrinsically disordered region shown to be involved in protein–protein interactions mediated via putative hydrophobic α-helix spanning residues (213–225 residues) [43].

### **6. Prospects**

The functional role of PTMs in SARS-CoV2 associated proteins has not been fully explored and many trials are needed for proposing the role of all types of glycosylation like N-linked and O-linked along with palmitoylation and phosphorylation in the initial phase of the infection. However multiple modification sites on the proteins of the SARS-CoV2 virus provides opportunities to explore more about the replication and pathogenesis of the virus into the host cells. Moreover, newer techniques for the detection of the PTMs are also needed to detect the modifications at multiple sites in dynamically changing virus structure. It is also needed in the current scenario to better understand the molecular mechanism of these PTMs. Also, the PTMs of the coronavirus proteins might be attractive targets for the therapeutic regime. PTMs of the coronavirus proteins might also provide a prospective target for the development of the vaccines.

*Fundamentals of Glycosylation*
