FIG 2.

Nanobody binding sites on the P dimer. The X-ray crystal structures of the P domain nanobody complexes were superimposed onto one P dimer in order to show all four nanobody binding sites. Nanobodies were colored accordingly: NB-5853, sky; NB-5867, purple; NB-5820, salmon; NB-5829, warm pink. NB-5853 and NB-5867 bound on the top of the P2 subdomain, whereas NB-5820 and NB-5829 bound on the side of the P1 subdomain and at a dimeric interface. The structure of the MNV P domain in complex with CD300lf (green) receptor and bile acid (orange) were superpositioned onto the P dimer.