HIV-1 TAT Protein Peptide is known to be a protein and particle transduction domain (PTD) and at the same time to comprise a nuclear localization function (NLS). Oligomers of the TAT (47-57) peptide compact plasmid DNA to nanometric particles and stabilize DNA towards nuclease degradation. At optimized vector compositions, these peptides mediate gene delivery to cells in culture six to eight times more efficiently than poly-L-arginine or the mutant TAT2-M1.