Structure of TFIIK for phosphorylation of CTD of RNA polymerase II

TFIIH is a 10-protein complex that is conserved through out eukaryotes. TFIIH has two primary cellular functions: transcription initiation and nucleotide excision repair (NER). In transcription initiation, TFIIH acts as a structural scaffold, phosphorylates the RNA polymerase II (pol II) C-terminal domain (CTD) and translocates promoter DNA through the pol II active site to facilitate start site selection. In NER, again is a structural scaffold, opens a bubble around damaged DNA and scans the damaged strand for bulky lesions. In yeast (Saccharomyces cerevisiae), TFIIH is composed of the two helicases Ssl2 and Rad3, the scaffolding subunits Tfb1, Tfb2, Tfb4 and Ssl1 and the kinase subunits Kin28, Ccl1 and Tfb3.