TAT TFA (YGRKKRRQRRR) is derived from the transactivator of transcription (TAT) of human immunodeficiency virus (HIV-1) and is a cell-penetrating peptide. TAT can increase the yields and the solubility of heterologous proteins[1].
TAT (YGRKKRRQRRR) represents amino acids 47-57 of the human immunodeficiency virus type I (HIV-1) TAT protein. The positively charged protein transduction domain of the HIV-1 TAT protein (TAT-PTD; residues 47-57 of TAT) rapidly translocates across the plasma membrane of living cells. TAT (YGRKKRRQRRR; TAT-PTD) can cross the hydrophobic lipid bilayer of a cell membrane simply by passive diffusion[1].
[1]. Ziegler A, et al. Interaction of the protein transduction domain of HIV-1 TAT with heparan sulfate: binding mechanism and thermodynamic parameters. Biophys J. 2004 Jan;86(1 Pt 1):254-63.