Characterisation of the RNA binding properties of the coronavirus infectious bronchitis virus nucleocapsid protein amino‐terminal region

The coronavirus nucleocapsid (N) protein binds viral RNA to form the ribonucleocapsid and regulate RNA synthesis. The interaction of N protein with viral RNA was investigated using circular dichroism and surface plasmon resonance. N protein underwent a conformational change upon binding viral RNA and the data indicated electrostatic interactions were involved in the binding of the protein to RNA. Kinetic analysis suggested the amino‐terminal region facilitates long‐range non‐specific interactions between N protein and viral RNA, thus bringing the RNA into close proximity to N protein allowing specific contacts to form via a ‘lure’ and ‘lock’ mechanism.