Abstract
The Gag and Nef proteins of human immunodeficiency type l (HIV-1) have conserved N-terminal sequences that appear essential for HIV-1 function. In view of the structural similarities a Gag peptide corresponding to myrGag2_22, was subjected to cytotoxicity tests employing recently developed cell assays. The Gag peptide displays a similar activity to Nef. The role of such sequences may be important in viral membrane association, viral biogenesis and transition of these proteins through the cellular membrane.