Fig. 1.

CDV-H structural model and localization of residues selected for alanine-scanning mutagenesis. (A) Primary structure of the H protein. CT, cytoplasmic tail; TM, transmembrane region; β1 to β6, color-coded β-propeller blades 1 to 6. (B) (Left) Top view of MeV-H (cartoon) in complex with CD46 (surface representation; dark blue) (PDB code 3INB) (28). (Right) Side view of MeV-H/CD46 (with CD46 removed). The color coding of β-strands corresponds to that in panel A. (C) Surface representation of MeV-H, shown in the same orientation as that on the right side of panel B. The curved black line indicates the top of the MeV-H β-propeller structure. The small socket (red asterisk) that locates the tip of the recessed groove (dashed red line) is indicated. Red, residues recently documented to contact SLAM (11); white, residues reported in MeV-H to contact CD46 (28); pink, residues shown to contact both CD46 and SLAM. Residues that support EpR-dependent fusion activity (16, 32) are shown in different colors: residue 482 in yellow, residue 497 in cyan, residue 541 in dark blue, and residue 543 in raspberry. Residues 482, 541, and 543 are also part of the SLAM and CD46 binding site. (D) Surface representation of the CDV-H structural model (based on MeV-H/CD46 [PDB code 3INB]), shown in the same orientation as that of MeV-H in panel C. Yellow, residues selected for alanine-scanning mutagenesis (20 amino acids) that potentially interact with multiple receptors used by CDV. Positions of selected residues are labeled in red. The small socket and the recessed groove (dashed red line) are also indicated.