CRYSTAL-STRUCTURE OF A TFIIB-TBP-TATA-ELEMENT TERNARY COMPLEX

The crystal structure of the transcription factor IIB (TFIIB)/TATA box -binding protein (TBP)/TATA-element ternary complex is described at 2. 7 Angstrom resolution, core TFIIB resembles cyclin A, and recognizes t he preformed TBP-DNA complex through protein-protein and protein-DNA i nteractions. The amino-terminal domain of core TFIIB forms the downstr eam surface of the ternary complex, where it could fix the transcripti on start site. The remaining surfaces of TBP and the TFIIB can interac t with TBP-associated factors, other class II initiation factors, and transcriptional activators and coactivators.