| Type: | Domain | Name: | Potyvirus NIa protease (NIa-pro) domain |
| Description: | Tobacco etch virus (TEV), tomato vein mottling virus (TVMV), and plum pox virus (PPV) are members of the Potyviridae family. The potyvirus genomeis a (+) stranded RNA and is translated into a single polyprotein upon infection, which is processed by the virally encoded proteases P1, HC-Pro, andNIa. Most of the cleavage events are performed by NIa (nuclear inclusion protein a) protease (NIa-pro). NIa-pro processes seven sites present in thepotyvirus polyprotein, named as A, B, C, D, V, E, and F. NIa-pros obtained from potyviruses have similar structures and functions. The potyvirus NIa-prohas a His-Asp-Cys catalytic triad, which is homologous to the trypsin-like proteases except for Cys replacing Ser. NIa-pros obtainedfrom potyviruses share certain sequence identities; however they recognise distinct amino acid sequences at each recognition sites. Consequently, theycannot recognise the cleavage sites of each other efficiently []. Nia-probelongs to peptidase family C4. In addition to the catalytic activity NIa-pro possesses also sequence non-specific RNA-binding activity and RNApolymerase (NIb) binding activity [].The potyvirus NIa protein contains the following two domains; the VPg domain at the N terminus and the NIa-pro domain at the C terminus [, ]. The ~250-amino acid NIaPro domain adopts the characteristic two-domain antiparallelbeta-barrel fold that is the hallmark of trypsin-like serine proteases, with the catalytic triad residues His, Asp, and Cys located at the interfacebetween domains [].This entry represents the NIa-pro domain. | Short Name: | Potyv_NIa-pro_dom |
