Fig. 3: Catalytically competent hPolμΔ2 active site geometry leads to nucleotide incorporation in crystallo.
From: Structural snapshots of human DNA polymerase μ engaged on a DNA double-strand break
a Structural snapshot of the hPolμΔ2 active site, exhibiting incomplete incorporation of the hydrolyzable dTTP nucleotide, with a zoomed view b of the primer terminal and unincorporated dUMPNPP (cyan) or newly incorporated TMP nucleotides. Protein components are shown as an orange ribbon; DNA is drawn in stick (colored as in Fig. 1a–b). Mg2+ ions are shown as purple spheres. The pyrophosphate (PPi) leaving group is drawn in green. c Fully post-catalytic nicked complex. Though Mg2+ fully occupies the B site in the post-catalytic complex, the A site metal has been partially replaced by Na+ (yellow). 2Fo-Fc electron density for active site components is shown as a gray mesh (contoured at 1σ). Red arrow indicates template backbone break. Superposition of hPolμΔ2 pre- (green; dUMPNPP in cyan) and post-catalytic nicked (purple; Na+ ion in yellow) complexes, shown as global d or zoomed in e views. Positional shifts are shown by black arrows, with the measured distances indicated.
