Chemical shift assignments of nsp7α from porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of porcine reproductive and respiratory syndrome, a destructive disease of swine. PRRSV has a single strand positive-sense RNA genome which contains at least ten open reading frames, of these, ORF1a and ORF1b encode polyproteins pp1a and pp1ab. Subsequently, pp1a is cleaved into ten nonstructural proteins, including nonstructural protein 7 alpha and 7 beta (nsp7 alpha and 7b), the internal cleavage products of a conserved nonstructural protein nsp7. Nsp7 plays a role in provoking the humoral immune system into producing anti-nsp7 antibodies which can be highly and persistently expressed in PRRSV-infected swine. However, the functions of nsp7 alpha and 7 beta remain unknown. Western blot and radioimmunoprecipitation analysis of the two proteins showed that only cleaved nsp7 alpha was detectable and cleaved nsp7 beta was not detected in the infected cells. Here, we reported the H-1, C-13 and N-15 resonance assignment of nsp7 alpha from PRRSV as a basis for further structural and functional studies.