RNA polymerase II and TAFs undergo a slow isomerization after the polymerase is recruited to promoter-bound TFIID.
Yakovchuk P, Gilman B, Goodrich JA, Kugel JF. RNA polymerase II and TAFs undergo a slow isomerization after the polymerase is recruited to promoter-bound TFIID. J Mol Biol. 2010 Mar 19; 397(1):57-68.