Tat conjugated peptides refers to peptides that are conjugated to peptides in turn derived from the trans-activator of transcription (Tat) protein of HIV-1.
Tat is a regulatory protein that consists of between 86 and 101 amino acids depending on the subtype, that drastically enhances the efficiency of viral transcription. Tat contains a protein transduction domain which allows it to enter cells by crossing the cell membrane. The amino acid sequence of the protein transduction domain is YGRKKRRQRRR and this property confers cell penetrating peptide properties on Tat and derivatives. Tat derived peptides belong to the cationic class of cell penetrating peptides which are peptides with highly positive net charges at physiological pH that primarily originate from the basic short strands of arginines and lysines.
Tat peptides have been widely used to deliver functional biomolecules into cells both in vitro and in vivo. The entire protein can be used but in practice it is more efficient to use truncated sequences containing only the basic residues required for transport. Through covalent attachment to Tat derived peptides, cargo molecules including proteins, nucleic acids, small molecules, oligonucleotides, enzymes, polymers, plasmid DNA and liposomes can be transported into cells with high efficiency.