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. Author manuscript; available in PMC: 2022 Jul 31.
Published in final edited form as: Curr Opin Struct Biol. 2022 Feb 17;73:102335. doi: 10.1016/j.sbi.2022.102335

Figure 4. Structural overview of the holo-PIC and DNA dynamics.

Figure 4.

A. Structure of the holo-PIC ready for promoter DNA opening (PDB ID 7ENC)[4]. Mediator (dark purple), TFIID (green), TFIIH (pink) and general transcription factors TFIIA, TFIIB, TFIIE, TFIIF, and TBP (gold, dark green, light pink, purple, and red) encircle Pol II from three sides. Template and non-template DNA are colored blue and cyan, respectively.

B. Conformational changes in the arrangement of Mediator, TFIID and TFIIH reposition the promoter DNA to form the promoter opening competent holo-PIC as shown in A (PDB ID 7ENC and 7ENA)[4]. Conformational changes are indicated by arrows.

C. DNA conformations of PIC-TFIID complexes in the presence or absence of TFIIE and/or TFIIH show transition of TATA-DPE promoter DNA from opening incompetent states (PDB ID 7EG7, blue and PDB ID 7EG9, teal)[16] to an opening competent state (PDB ID 7EGB, green)[16]. TATA-less promoter DNA immediately adopts the opening competent state.