Binding of an N protein peptide to M protein of a bat coronavirus

The interaction between the membrane (M) protein and the nucleocapsid (N) protein of coronaviruses plays a crucial role in virus assembly and morphogenesis. Previous studies indicate that one M−N interaction occurs between M protein and the carboxy-terminus of N protein. However, the mechanistic details of M−N interactions remain unclear. Here, we present a complex structure of an N protein carboxy-terminal peptide bound to M protein from Pipistrellus bat coronavirus HKU5. The structure shows that the M−N peptide binding site includes a “horizontal” groove located between the carboxy-terminal domain and the transmembrane domain of M protein. Combined with molecular docking and binding analysis, our results provide structural insight into the binding mechanism between M and N proteins of a coronavirus.