TFIIB is an essential component of the machinery that transcribes protein-coding genes. The three-dimensional structure of the human TFIIB core domain (TFIIBc) has been determined using multidimensional heteronuclear magnetic resonance spectroscopy. The molecule consists of two direct repeats that adopt similar α-helical folds, conferring pseudo-twofold symmetry. An extensive, central basic surface including an amphipathic a helix is critical to the function of TFIIB as a bridge between the TBP-promoter complex and RNA polymerase II and associated general and regulatory transcription factors. Similarities between the TFIIBc and cyclin A folds indicate that elements of the eukaryotic cell cycle control apparatus evolved from more fundamental transcriptional control components, demonstrating a link between the transcription and cell cycle molecular machineries. © 1995.
Bagby, S., Kim, S., Maldonado, E., Tong, K. I., Reinberg, D., & Ikura, M. (1995). Solution structure of the c-terminal core domain of human TFIIB: Similarity to cyclin A and interaction with TATA-binding protein. Cell, 82(5), 857–867. https://doi.org/10.1016/0092-8674(95)90483-2