Figure 9.

Comparison of WT Pol β and I260Q T:G mismatched incorporation at pH 7.6. Reactions were initiated by rapid mixing of equal volumes of solution A (containing 1 μM Pol β or I260Q and 400 nM 19/36AP(T)/15) and solution B (containing 4 mM dGTP) and performed at 37 °C in Pol β assay buffer at pH 7.6 containing 5 mM free Mg²⁺ and 10% glycerol. Fast and slow phase misincorporation rates were 70 ± 5 s⁻¹ and 0.25 ± 0.0004 s⁻¹ respectively for WT, and 314 ± 22 s⁻¹ and 1.7 ± 0.003 s⁻¹ respectively for I260Q. The insets show a close-up of the fast phases for WT (red trace) and I260Q (blue trace).