2ca1 | pdb_00002ca1
Crystal structure of the IBV coronavirus nucleocapsid
Structural highlights
FunctionNCAP_IBVB Packages the positive strand viral genome RNA into a helical ribonucleocapsid (RNP) and plays a fundamental role during virion assembly through its interactions with the viral genome and membrane protein M. Plays an important role in enhancing the efficiency of subgenomic viral RNA transcription as well as viral replication.[HAMAP-Rule:MF_04097] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCoronaviruses cause a variety of respiratory and enteric diseases in animals and humans including severe acute respiratory syndrome. In these enveloped viruses, the filamentous nucleocapsid is formed by the association of nucleocapsid (N) protein with single-stranded viral RNA. The N protein is a highly immunogenic phosphoprotein also implicated in viral genome replication and in modulating cell signaling pathways. We describe the structure of the two proteolytically resistant domains of the N protein from infectious bronchitis virus (IBV), a prototype coronavirus. These domains are located at its N- and C-terminal ends (NTD and CTD, respectively). The NTD of the IBV Gray strain at 1.3-A resolution exhibits a U-shaped structure, with two arms rich in basic residues, providing a module for specific interaction with RNA. The CTD forms a tightly intertwined dimer with an intermolecular four-stranded central beta-sheet platform flanked by alpha helices, indicating that the basic building block for coronavirus nucleocapsid formation is a dimeric assembly of N protein. The variety of quaternary arrangements of the NTD and CTD revealed by the analysis of the different crystal forms delineates possible interfaces that could be used for the formation of a flexible filamentous ribonucleocapsid. The striking similarity between the dimeric structure of CTD and the nucleocapsid-forming domain of a distantly related arterivirus indicates a conserved mechanism of nucleocapsid formation for these two viral families. X-ray structures of the N- and C-terminal domains of a coronavirus nucleocapsid protein: implications for nucleocapsid formation.,Jayaram H, Fan H, Bowman BR, Ooi A, Jayaram J, Collisson EW, Lescar J, Prasad BV J Virol. 2006 Jul;80(13):6612-20. PMID:16775348[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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