SignalScan^™ Peptide Mix (SARS-CoV-2)

The SignalScan™ Peptide Mix (SARS-CoV-2) enables targeted analysis of selected peptides in human-sourced cells or tissues. Peptides and phosphopeptides derived from SARS-CoV-2 spike and nucleocapsid proteins as well as nine human host response proteins are included. This mixture contains 96 pmol each of 25 heavy-labeled (13C, 15N) Stable Isotope Standard (SIS) peptides, quantified by amino acid analysis (AAA). Inclusion of SIS peptides enhances the sensitivity of the LCMS assay by acting as a trigger for targeted MS/MS analysis. Targeted assays ensure that peptides present in the biological sample of interest are consistently observed and sensitivity is maximized. SIS-assisted scanning provides the sensitivity of a parallel reaction monitoring (PRM) assay without use of rigid retention time windows. Full peptide list, detailed protocol, and files for method set-up and data analysis are available for download at http://media.cellsignal.cn/www/zip/proteomics/signalscan-peptide-mix.zip.

The cause of the COVID-19 pandemic is a novel and highly pathogenic coronavirus, termed SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2). SARS-CoV-2 is a member of the Coronaviridae family of viruses (1). The genome of SARS-CoV-2 is similar to other coronaviruses, and is comprised of four key structural proteins: S, the spike protein, E, the envelope protein, M, the membrane protein, and N, the nucleocapsid protein (2). Coronavirus spike proteins are class I fusion proteins and harbor an ectodomain, a transmembrane domain, and an intracellular tail (3,4). The highly glycosylated ectodomain projects from the viral envelope surface and facilitates attachment and fusion with the host cell plasma membrane. The ectodomain can be further subdivided into host receptor-binding domain (RBD) (S1) and membrane-fusion (S2) subunits, which are produced upon proteolysis by host proteases at S1/S2 and S2’ sites. S1 and S2 subunits remain associated after cleavage and assemble into crown-like homotrimers (2,4). In humans, both SARS-CoV and SARS-CoV-2 spike proteins utilize the angiotensin-converting enzyme 2 (ACE2) protein as a receptor for cellular entry (5-7). The cell’s subsequent host response to SARS-CoV-2 infection involves complex signaling cascades, observable through perturbations in protein phosphorylation patterns (8,9) that lead to interferon and cytokine production (10).