TATA-binding protein (TBP) is a ubiquitously expressed nuclear protein that functions at the core of the general transcription factor protein complex TFIID . TFIID, which contains TBP and 13 TBP-associated factors (TAFs), contributes to the formation of the transcription pre-initiation complex, an assembly of multiple protein complexes (TFIIA, TFIIB, TFIIE, TFIIF, TFIIH, and RNA polymerase II) that bind to a gene promoter during the initiation of transcription. A distinctive feature of TBP is a long string of glutamines in the N-terminus. This region of the protein modulates the DNA binding activity of the C terminus, and modulation of DNA binding affects the rate of transcription complex formation and initiation of transcription.
