Fig. 1: Structure of mismatched (A:C) DNA-Polζ ternary complex.
From: Cryo-EM structure of translesion DNA synthesis polymerase ζ with a base pair mismatch
For the mismatched (A:C) DNA-Polζ ternary complex, the NTD (N-terminal domain), Exo (Exonuclease), RIR (Rev7 interacting region), fingers, palm, thumb, CTD (C-terminal domain) of Rev3 are shown in blue, magenta, brown, yellow, cyan, orange, and light gray, respectively; Rev7A and Rev7B in green; Pol31 and Pol32N in purple and salmon, respectively; and the DNA and incoming dCTP in red. For comparison, the matched (G:C) DNA-Polζ ternary complex7 (PDB ID: 6V93) is shown below following the same color scheme, except for the fingers domain depicted in wheat color and the DNA and incoming dCTP in gray. The figure also displays the palindromic template-primer DNA sequences and the dCTP used to reconstitute the ternary complexes with Polζ. The right panel displays a close-up view of the region around the DNA, upon an ~90° clockwise rotation of the structure along the y-axis, depicting the fingers helices αF, αxA, and αxB in a closed (matched DNA complex) and open (mismatched DNA complex) conformation. An arc arrow highlights the ~15°outward movement of the fingers domain in the mismatched DNA complex relative to the matched DNA complex. Also highlighted in sticks are the active site residues D975 and D1144. Green spheres depict the active site metal B in the mismatched DNA complex and the active site metals A and B in the matched DNA complex.
