Human General Transcription Factor TFIIB, C-Terminal Core Domain

The human general transcription factor TFIIB participates in the activation of eukaryotic protein-encoding genes transcribed by RNA polymerase II. More specifically, TFIIB plays a central role in the transcription of class II genes. It associates with the TFIID-IIA DNA-bound complex to form the TFIID-IIA-IIB, or DAB complex. It is the DAB complex which RNA polymerase II recognizes.
The C-terminal core domain of human TFIIB, or TFIIBc, is 208 amino acid residues long. Structurally, this protein is made up of 2 direct repeats with similar alpha-helical folds. It consists of 11 alpha helices, 2 of which are 310 alpha helices (shown in green). The TFIIBc fold is very similar to that of cyclin A suggesting an evolutionary link between the eukaryotic cell cycle control apparatus and transcriptional control components.


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