Fig. 1.

Ferret CD4 protein has a higher amino acid identity to mouse CD4 than human. Phylogenetic tree shows the homology of the CD4 amino acid sequences between ferret and other species (a). The table shows the percent identity of CD4 between ferret, mouse and human amino acid and nucleic acid sequences (b). The 3D predicted structure of mouse and ferret CD4 molecule, smooth curved lines depict polypeptide backbones, whereas the β-strands are displayed as thick coloured arrows and indicate the direction of the polypeptide chain (c). Arrows indicate some of the possible surface difference between the two molecules.