FIG. 1.
Structural features of HIV-1 Vif. The highly conserved SLQYLA motif (amino acids 144 to 153) in Vif forms a BC box that interacts with ElonginC (EloC) (16, 19, 24, 43, 44). Amino acids 108 to 139 in Vif form a highly conserved H-X5-C-X17-18C-X3-5-H motif that mediates the interaction with Cul5 (19). The N-terminal region of HIV-1 Vif has been implicated in the interaction with A3G (23). This region is unusually rich in tryptophans. The indicated mutants were constructed to evaluate the functions of conserved Trp residues.