The third helix of the Antennapedia homeodomain translocates through biological membranes

摘要: The 60-amino acid long homeodomain of Antennapedia crosses biological membranes by an energy-independent mechanism, a phenomenon abolished directed mutagenesis within the polypeptide C-terminal region. This finding led us to study internalization several chemically synthesized peptides derived from third helix homeodomain. We report here that 16 amino acids in length corresponding deleted its N-terminal glutamate is still capable translocating through membrane. A longer peptide 20 also translocates, whereas shorter (15 acids) are not internalized cells. As case for entire homeodomain, 20- and 16-amino at 4 degrees C, suggesting mechanism translocation involving classical endocytosis. two translocated can be recovered, intact, cells, strongly they targeted lysosomal compartment. Finally, substitution tryptophans phenylalanines diminishes translocation, raising possibility solely based on general hydrophobicity.