SARS-CoV-2 is an enveloped single-stranded, positive-sense RNA virus. The SARS-CoV-2 nucleocapsid (N) protein is essential for viral RNA replication and new virion assembly. The N protein assembles the positive strand viral genome RNA forming a helical ribonucleocapsid (RNP) during the packaging of the RNA genome. The N protein is also involved in regulating viral RNA synthesis during replication and RNA transcription and modulating metabolism in infected subjects.

The lysine residue at position 16 of this peptide is isotopically labelled with carbon-13 (6) and nitrogen-15 (2), giving this peptide a mass increase of 8 compared to the unlabelled peptide.