FIG 1.

Alignment of Nef amino acid sequences differing specifically in the TCR-CD3 downmodulation function. The SIVmac239 Nef is shown on top for comparison. The myristoylated N terminus, a basic N-proximal region, the CD4 interaction site, the acidic region, and the PxxP motif, as well as the ExxxL/V/M adaptor protein interaction site in the flexible C-loop region, are indicated. Amino acid positions in the core region specifically involved in downmodulation of TCR-CD3 are highlighted by yellow bars. Dashes indicate gaps introduced to optimize the alignment.