The SARS-CoV-2 nucleocapsid (N) protein is an abundant RNA-binding protein critical for viral genome packaging, yet the molecular details that underlie this process are poorly understood. Here we combine single-molecule spectroscopy with all-atom simulations to uncover the molecular details that contribute to N protein function. N protein contains three dynamic disordered regions that house putative transiently-helical binding motifs. The two folded domains interact minimally such that full-length N protein is a flexible and multivalent RNA-binding protein. N protein also undergoes liquid-liquid phase separation when mixed with RNA, and polymer theory predicts that the same multivalent interactions that drive phase separation also engender RNA compaction. We offer a simple symmetry-breaking model that provides a plausible route through which single-genome condensation preferentially occurs over phase separation, suggesting that phase separation offers a convenient macroscopic readout of a key nanoscopic interaction. SARS-CoV-2 nucleocapsid (N) protein is responsible for viral genome packaging. Here the authors employ single-molecule spectroscopy with all-atom simulations to provide the molecular details of N protein and show that it undergoes phase separation with RNA.
【저자키워드】 Computational models, Intrinsically disordered proteins, Single-molecule biophysics, 【초록키워드】 Polymer, RNA, Protein, Region, N protein, molecular, Critical, predict, binding, Interaction, motifs, viral genome, domain, SARS-CoV-2 nucleocapsid, full-length, offer, flexible, responsible, provide, contribute, occur, underlie, macroscopic, single-genome, 【제목키워드】 RNA, Protein, SARS-CoV-2 nucleocapsid,