General transcription factor that functions at the core of the DNA-binding multiprotein factor TFIID. Binding of TFIID to the TATA box is the initial transcriptional step of the pre-initiation complex (PIC), playing a role in the activation of eukaryotic genes transcribed by RNA polymerase II. Belongs to the TFIID complex together with the TBP-associated factors (TAFs). Binds DNA as monomer. Belongs to the TBP family.