TAT - HA2 Fusion Peptide RRRQRRKKRGGDIMGEWGNEIFGAIAGFLG
This sequence is amino acids 1 to 20 of influenza A virus hemagglutinin protein (HA2) connected to a 10 amino acid cell permeable HIV Trans-Activator of Transcription (TAT) protein transduction domain (PTD). TAT-HA2 is capable of being used as a large macromolecule drug delivery peptide. The TAT PTD binds to the cell surface and penetrates the membrane via lipid raft-dependent macropinocytosis. Endosomal escape and transduction of the fusion peptide are enhanced by the HA2 domain, which is a pH-sensitive lipid membrane destabilizing sequence.