Dear Editor, The COVID-19 pandemic worldwide is caused by a novel coronavirus SARS-CoV-2 (the severe acute respiratory syndrome coronavirus 2). 1 After viral invasion into the host cells, the~30 kb viral genome RNA injected is translated into structural and nonstructural proteins to replicate viral genome and assemble more viral particles. Many copies of nucleocapsid (N) protein can bind to viral genome RNA and pack it into~100 nm particles, assisting membrane (M) and envelope (E) proteins to efficiently assemble the viral envelope. 2 The exact molecular mechanism by which N protein packs up the viral genome still remains elusive. An N protein of SARS-CoV-2 consists of an N-terminal RNAbinding domain (NTD) and a C-terminal dimerization domain (CTD) and shares~90% sequence identity with N protein of SARS-CoV (Supplementary information, Fig. S1a). The regions located between the N-terminus and NTD, between NTD and CTD, and between CTD and the C-terminus of the N protein of SARS-CoV-2 (thereafter referred to as N protein) are predicted to be intrinsically disordered (Supplementary information, Fig. S1b, c). At neutral pH, the N protein is positively charged (+24 e), consistent with its strong binding affinity with negatively charged