Dhamotharan Karthikeyan, Korn Sophie M, Wacker Anna, Becker Matthias A, Günther Sebastian, Schwalbe Harald, Schlundt Andreas
Institute for Molecular Biosciences, Goethe University, Frankfurt, Germany.
Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Frankfurt, Germany.
Nat Commun. 2024 Dec 9;15(1):10656. doi: 10.1038/s41467-024-55024-0.
The SARS-CoV-2 nucleocapsid protein is indispensable for viral RNA genome processing. Although the N-terminal domain (NTD) is suggested to mediate specific RNA-interactions, high-resolution structures with viral RNA are still lacking. Available hybrid structures of the NTD with ssRNA and dsRNA provide valuable insights; however, the precise mechanism of complex formation remains elusive. Similarly, the molecular impact of nucleocapsid NTD mutations that have emerged since 2019 has not yet been fully explored. Using crystallography and solution NMR, we investigate how NTD mutations influence structural integrity and RNA-binding. We find that both features rely on a core network of residues conserved in Betacoronaviruses, crucial for protein stability and communication among flexible loop-regions that facilitate RNA-recognition. Our comprehensive structural analysis demonstrates that contacts within this network guide selective RNA-interactions. We propose that the core network renders the NTD evolutionarily robust in stability and plasticity for its versatile RNA processing roles.
严重急性呼吸综合征冠状病毒2（SARS-CoV-2）核衣壳蛋白对于病毒RNA基因组加工至关重要。尽管有人提出N端结构域（NTD）介导特定的RNA相互作用，但仍缺乏与病毒RNA的高分辨率结构。现有的NTD与单链RNA和双链RNA的杂交结构提供了有价值的见解；然而，复合物形成的确切机制仍然难以捉摸。同样，自2019年以来出现的核衣壳NTD突变的分子影响尚未得到充分探索。我们利用晶体学和溶液核磁共振技术，研究NTD突变如何影响结构完整性和RNA结合。我们发现这两个特征都依赖于β冠状病毒中保守的核心残基网络，这对于蛋白质稳定性以及促进RNA识别的柔性环区域之间的通讯至关重要。我们全面的结构分析表明，该网络内的接触引导选择性RNA相互作用。我们提出，核心网络使NTD在稳定性和可塑性方面具有进化上的稳健性，以发挥其多样的RNA加工作用。
