ジャーナル: J Struct Biol / 年: 2025 タイトル: Characterization of SARS-CoV-2 nucleocapsid protein oligomers. 著者: Domenica Farci / André T Graça / Michael Hall / Patrycja Haniewicz / Sami Kereïche / Peter Faull / Joanna Kirkpatrick / Enzo Tramontano / Wolfgang P Schröder / Dario Piano / 要旨: Oligomers of the SARS-CoV-2 nucleocapsid (N) protein are characterized by pronounced instability resulting in fast degradation. This property likely relates to two contrasting behaviors of the N ...Oligomers of the SARS-CoV-2 nucleocapsid (N) protein are characterized by pronounced instability resulting in fast degradation. This property likely relates to two contrasting behaviors of the N protein: genome stabilization through a compact nucleocapsid during cell evasion and genome release by nucleocapsid disassembling during infection. In vivo, the N protein forms rounded complexes of high molecular mass from its interaction with the viral genome. To study the N protein and understand its instability, we analyzed degradation profiles under different conditions by size-exclusion chromatography and characterized samples by mass spectrometry and cryo-electron microscopy. We identified self-cleavage properties of the N protein based on specific Proprotein convertases activities, with Cl playing a key role in modulating stability and degradation. These findings allowed isolation of a stable oligomeric complex of N, for which we report the 3D structure at ∼6.8 Å resolution. Findings are discussed considering available knowledge about the coronaviruses' infection cycle.