Domain structure of the vertebrate TBP family. The core domain (blue) is formed by an imperfect direct repeat (blue) and is involved in binding to the TATA box in the case of TBP and TBP2. TLF lacks an N-terminal domain. The N-terminal domain of TBP2 is not as well conserved as the core domain. The PXT repeats in the N-terminal domain are indicated (green), as well as the poly-glutamine stretch of TBP (orange).