Identification of SARS-CoV-2 main protease cleavage sites in host cellular selenoproteins and glutathione-related proteins

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Ignacio A. Gallardo (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Ethan Taylor

Abstract: SARS-CoV-2 (severe acute respiratory syndrome-coronavirus-2) continues to be a global threat. Even as vaccines and therapeutics become increasingly available, COVID-19 (Coronavirus Disease-2019) infections continue to rise, leading to the proliferation of even more transmissible variants. Although the current Omicron variant appears to be milder in pathogenicity when compared to previous strains of the virus, it is said to be about three times more infectious than its predecessor, the Delta variant, thus greatly increasing the chances of more breakthrough infections. Therefore, it has become increasingly important that we understand the mechanisms by which this virus operates in order to find ways to decrease the rates of infection/replication. One viral mechanism of interest is that of the SARS-CoV-2 Main Protease (Mpro), also known as the 3CL Protease. This protease plays vital roles in viral gene expression and replication via the proteolytic processing of two overlapping polyproteins encoded by the virus’ replicase gene. However, recent studies, including the one from our group, have shown that Mpro may also be targeting certain host cellular proteins that possess short stretches of homologous host-pathogen protein sequences (SSHHPS) corresponding to the canonical Mpro cleavage sites. Of particular interest are those with sequences resembling the P1, P2, P1’, and P4 positions of SARS-CoV-2’s non-structural proteins (NSPs), as those are the ones in direct contact with Mpro’s active site. Relating to the established link between selenium and viral pathogenesis, the goal of this study was to assess whether SARS-CoV-2 Mpro is targeting essential host selenoproteins and other glutathione-related proteins. Various in silico methods, including NetCorona, PROSPER, Procleave, and 3D modeling were utilized in the prediction of six potential Mpro cleavage sites. The validity of these sites was assessed by incubating recombinant SARS-CoV-2 Mpro with 10 12-mer peptides corresponding to the proposed cleavage sites in each selected protein, and analyzing their cleavage via mass-spectrometry-based methods. Definitive in vitro cleavage was observed in those within thioredoxin reductase-1 (TXNRD1), glutamate-cysteine ligase catalytic subunit (GCLC), Selenoprotein F (SelenoF), and Selenoprotein P (SelenoP). These results, not only support our hypothesis, but have broad implications for the ways we view prevention, treatment, and the evolution of SARS-CoV-2.

Additional Information

Language: English
Date: 2022
Coronavirus, COVID-19, SARS-CoV-2, Selenium, Selenoprotein, Vitamin D
COVID-19 (Disease)
Proteolytic enzymes
Scission (Chemistry)

Email this document to