Figure 4: Sequence alignments of the nucleocapsid (N) protein of the PA8, Lelystad and Euro-PRRSV SD01-08 genotypes. The cysteine residues are bolded. While PA8 contains 3 cysteine residues at position 23, 75 and 90 of the capsid protein, the European and the Euro-PRRSV in North America contain only 2 cysteine residues at 23 and 75.