TFIIE_beta_winged_helix domain, located at the central core region of TFIIE beta, with double-stranded DNA binding activity
Transcription Factor IIE (TFIIE) beta winged-helix (or forkhead) domain is located at the central core region of TFIIE beta. The winged-helix is a form of helix-turn-helix (HTH) domain which typically binds DNA with the 3rd helix. The winged-helix domain is distinguished by the presence of a C-terminal beta-strand hairpin unit (the wing) that packs against the cleft of the tri-helical core. Although most winged-helix domains are multi-member families, TFIIE beta winged-helix domain is typically found as a single orthologous group. TFIIE is one of the six eukaryotic general transcription factors (TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH) that are required for transcription initiation of protein-coding genes. TFIIE is a heterotetramer consisting of two copies each of alpha and beta subunits. TFIIE beta contains several functional domains, an N-terminal serine-rich region, a central core domain exhibiting a winged-helix structure capable of binding double-stranded DNA, a leucine repeat, a sigma3 region, and a C-terminal domain containing two basic regions. The assembly of transcription preinitiation complex (PIC) includes the general transcription factors and RNA polymerase II (pol II) initiated by the binding of the TBP subunit of TFIID to the TATA box, followed by either the sequential assembly of other general transcription factors and pol II or a preassembled pol II holoenzyme pathway. TFIIE interacts directly with TFIIF, TFIIB, pol II, and promoter DNA. TFIIE recruits TFIIH and regulates its activities. TFIIE and TFIIH are also important for the transition from initiation to elongation.