Titratable residues within the influenza virion.

Residues may reside at the c-terminus (c), n-terminus (n), or within the chain (s). For each residue type, the corresponding pKa value (from ref [12]) is given. The total count of each residue in a single virion was estimated by counting each residue type in the sequence of each protein, then multiplying by the copy number of that protein, then summing for all proteins.