Fig. 2.

Comparative sequence analysis of the nsp1α/nsp1β and nsp1β/nsp2 cleavage sites. Partial ORF1a amino acid sequence of six PRRSV strains corresponding to SD23983 ORF1a amino acid position 160–204 and 361–409 was aligned with EAV nsp1. The alignment was generated by ALIGNX program of Vector NTI Suite software (InforMax, Inc.). Two boxes depicted in the map of amino acid sequence comparison represent the result of nsp1β and nsp2 protein N-terminal sequencing, which was determined by sequential Edman degradation of 10 cycles for each viral protein. The upward and downward solid arrows point to the identified cleavage site of nsp1β/nsp2 and nsp1α/nsp1β, respectively. The downward dashed arrow points to the predicted nsp1α/nsp1β cleavage site.