O-61 - Three predicted O-linked glycosylation sites flank the SARS-CoV-2 furin cleavage site
The proline in the inserted PRRA is predicted to create O-linked glycans at residues S673, T678 and S686 flanking the furin cleavage site.
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Why this is evidence
Predicted O-linked glycans flanking the furin site are consistent with selection in an immunocompetent host and hard to obtain in cell culture — favouring the natural members (H-41/H-42) over cell-culture engineering (H-43).