| Primary Identifier | IPR046440 | Type | Domain |
| Short Name | AV_NSP11N_COV_NSP15M |
| description | Positive-stranded RNA (+RNA) viruses that belong to the order Nidovirales infect a wide range of vertebrates (families Arteriviridae and Coronaviridae) or invertebrates (Mesoniviridae and Roniviridae). Examples of nidoviruses with high economic and societal impact are the arterivirus porcine reproductive and respiratory syndrome virus (PRRSV) and the zoonotic coronaviruses (CoVs) causing severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and Covid-19 (SARS-CoV-2) in humans. The replicase gene encodes two polyproteins, pp1a and pp1ab, which are proteolytically processed to nonstructural proteins (NSPs). Among the NSPs found in Nidovirales, nonstructural protein 15 (NSP15) from coronaviruses (CoV) and NSP11 from arteriviruses (AV) participate in the viral replication process and in the evasion of the host immune system. They contain in their C-terminal region a conserved endoribonuclease domain called nidoviral uridylate-specific endoribonuclease (NendoU) with cleavage specificity for single- and double-stranded RNA 5' of uridine nucleotides to produce a 2'-3'-cyclic phosphate end product. Arterivirus Nsp11 contains two conserved compact domains: the N-terminal domain (NTD) and C-terminal domain (NendoU), whereas CoV NSP15 folds into three domains: N-terminal, middle domain, and C-terminal catalytic NendoU domain. No counterpart corresponding to the NTD of CoV NSP15 exists in AV NSP11. The NTD of AV NSP11 is small and related to NSP15 middle domain, which may serve as an interaction hub with other proteins and RNA [, , , , , ].This domain contains a central β-sheet flanked by two small α-helices on either side [, , ]. |
