Cartoon drawings for the superposition of the FLUAV N protein with that of the VSV N protein (gray). (a) Superposition of the FLUAV N protein as in the reported crystal structure. Only the C-terminal domain of the putative RNA binding region of the FLUAV N protein was included in the calculation for the structural alignment by FATCAT . The N-terminal domain of the putative RNA binding region in the FLUAV N protein was colored green, the C-terminal domain, yellow, and the addition domain at the C-terminal end of the FLUAV N protein, blue. (b) Superposition of a hypothetical structure of the FLUAV N protein with the structure of the VSV N protein. The orientation of the C-terminal domain is the same in (a) and (b). The N-terminal domain (green) was aligned with the N-terminal domain of the VSV N protein as in Figure 5. The additional domain at the C-terminal end (blue) was positioned by twisting the torsion angles of the peptide chain including residues 295–297 (indicated by the red arrow) to match the loop at the end of the VSV C-terminal domain.