Fig. 2: Structure of the Pol I OC with A49 tWH contacting promoter DNA.
From: Molecular insight into RNA polymerase I promoter recognition and promoter melting
a The structure of the Pol I OC2 is coloured as in Fig. 1a. The clamp coiled-coil is highlighted in light orange. Cryo-EM density of the sharpened globally refined maps is shown for both DNA strands. b Top view of the OC2. c The clamp is more closed in the OC2 (light orange) than in the OC1 (light green) allowing the A49 linker to wrap around the coil-coil and A49 tWH to contact the promoter. Models were aligned on subunit A135. d The position of the upstream DNA (dark blue) and A49 tWH in the OC2 (dark purple) is compared with that in the Pol I EC (upstream DNA in light blue (PDB: 5M5X) [http://dx.doi.org/10.2210/pdb5m5x/pdb] and A49 tWH in light pink (PDB: 5M64) [http://dx.doi.org/10.2210/pdb5m64/pdb]). The movement of the A49 tWH is indicated by the orange arrow. The asterisks indicate residue Q252 in the OC2 and EC. Structures are aligned on subunit A135 as in c.
