| The DNA binding domain of the Drosophila transcription factor (Antennapedia), a 60 amino acid protein, has the ability to penetrate biological membranes. The 16-mer peptide (RQIKIWFQNRRMKWKK), residues 43-58, known as penetratin, from antennapedia preferentially targets the Class I pathway. The peptide has the same translocating properties as the entire protein and can facilitate the cytoplasmic uptake of CTL epitope 9-mer peptides. For CRQIKIWFQNRRMKWKKGG, the extra cysteine is used for the downstream conjugation. |