The fundamental transcription factor TFIIB has the characteristics of stabilizing the DNA binding of TATA box-binding protein (TBP) and binding directly to DNA by its conformational change. Also its N terminal region binds to the RNA channel of RNA polymerase undertaking a very important role in the determination of transcription initiation point and promoter clearance. Sua7p is the TFIIB of budding yeast and is composed of 346 amino acid residues.