TFIIA changes the conformation of the DNA in TBP/TATA complexes and increases their kinetic stability.
Hieb AR, Halsey WA, Betterton MD, Perkins TT, Kugel JF, Goodrich JA. TFIIA changes the conformation of the DNA in TBP/TATA complexes and increases their kinetic stability. J Mol Biol. 2007 Sep 21; 372(3):619-32.