Fig. 2.

Mediator Core–ITC Architecture. The structure of a Mediator core bound to an initially transcribing RNA pol II-containing complex (EMD-2786; PDB ID: 4V1O) is shown in two views related by a 180° rotation along the vertical axis (arrow). TBP (green), promoter DNA (yellow and green), TFIIB (blue), TFIIF (purple), and the mediator Head module are depicted in a cartoon representation based on X-ray crystal structure coordinates. RNA Pol II is colored in gray. Mediator Middle Module (Knob, Hook) is colored in orange. The structure was determined by cryo-EM combined with CLMS and by fitting of available atomic coordinates (adapted from Ref. [24]).