NP–RNA interactions in the helical NP(full)–RNA complex. (a) The overall structure of the protomeric NP(full)–RNA complex in cylindrical presentation (colored the same as Fig. 1a). (b) Close-up view of the RNA binding site. Hydrogen bonds (distance < 4 Å) were detected by ChimeraX (35) and shown as blue dotted lines. (c) Close-up view of the RNA binding site. Positively charged amino acids are marked. (d) Schematic diagram of the NP–RNA interactions. The RNA bases are numbered in the 3′ to 5′ direction. The RNA bases on the helix, facing inward (light-orange) and outward (light-brown). Secondary structure labels are based on our atomic model. Orange dotted lines represent the potential interactions between the NP residues and RNA backbone.