Fig. 5. Titration of the Me²⁺_A on primer 3′-OH alignment.

a Structure of Pol η:dGMPNPP with 2.0 mM Mg²⁺. b Plot showing Mg²⁺_A density and omit map electron density for the down primer with Mg²⁺ concentration. c Correlation (R²) between the Mg²⁺_A density and omit map electron density for the down primer. d Structure of Pol η:dGMPNPP with 3.0 mM Mn²⁺. e Plot showing Mn²⁺_A density and omit map electron density for the down primer with Mn²⁺ concentration. f Correlation (R²) between the Mn²⁺_A density and omit map electron density for the down primer conformation. The 2F_o-F_c map for the primer up conformation (blue) was contoured at 2 σ in (a) and 1.5 σ in (d). The F_o-F_c omit map for both the Me²⁺_A and primer down conformation (red) were contoured at 3 σ. All data points shown in the plot were collected at t  =  600 s and represent singular measurements.