Furin --> A protein. https://en.wikipedia.org/wiki/Furin https://en.wikipedia.org/wiki/Furin Spike protein --> the proteins on the surface of a virus used to a

Furin --> A protein. https://en.wikipedia.org/wiki/Furin https://en.wikipedia.org/wiki/Furin Spike protein --> the proteins on the surface of a virus used to attach onto or enter a host cell. https://en.wikipedia.org/wiki/Peplomer https://en.wikipedia.org/wiki/Peplomer RRAR --> This is a group of amino acids: Arginine Arginine Alanine Arginine. Here is the list of abbreviations: https://www.ncbi.nlm.nih.gov/Class/MLACourse/Modules/MolBioReview/iupac_aa_abbreviations.html https://www.ncbi.nlm.nih.gov/Class/MLACourse/Modules/MolBioR... For a discussion of cleavage --> https://en.wiktionary.org/wiki/endoproteolytic https://en.wiktionary.org/wiki/endoproteolytic For a discussion of it relevant to another virus --> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC103966/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC103966/ Mucin --> https://en.wikipedia.org/wiki/Mucin https://en.wikipedia.org/wiki/Mucin O-Glycosylation --> https://en.wikipedia.org/wiki/O-linked_glycosylation https://en.wikipedia.org/wiki/O-linked_glycosylation So this is a discussion of the differences in how these viruses uses their respective spike proteins to trigger endoproteolytic cleavage in the host cell. Specifically, what the impact of different positionings of their amino acids is. For example, the idea "Furin-sensitive motif" means that there is a section of the spike protein which contains the amino acids described (RRAR), which is sensitive to the protein Furin in host cells. See here as well: https://www.researchgate.net/publication/6756975_Proteolysis_of_Sars-Associated_Coronavirus_Spike_Glycoprotein https://www.researchgate.net/publication/6756975_Proteolysis...