Table 1.
Steady-state kinetic parameters for nucleotide incorporation opposite the two diastereomers of N2-CEdG and unmodified dG by E. coli DNA polymerase IV (Km and Vmax are average values based on three independent measurements)
| dNTP | Vmax, nM min−1 | Km, nM | Vmax/Km, min−1 | finc |
|---|---|---|---|---|
| S-N2-CEdG-containing substrate | ||||
| dATP | 0.62 ± 0.07 | (8.41 ± 0.74) × 105 | 7.37 × 10−7 | 2.91 × 10−4 |
| dGTP | 0.23 ± 0.02 | (6.83 ± 0.63) × 105 | 3.36 × 10−7 | 1.33 × 10−4 |
| dCTP | 0.19 ± 0.02 | 75 ± 8.4 | 2.53 × 10−3 | 1.00 |
| dTTP | 0.46 ± 0.06 | (5.83 ± 0.68) × 105 | 7.89 × 10−7 | 3.12 × 10−4 |
| R-N2-CEdG-containing substrate | ||||
| dATP | 0.16 ± 0.01 | (7.90 ± 0.89) × 105 | 2.02 × 10−7 | 1.44 × 10−4 |
| dGTP | 0.49 ± 0.08 | (1.49 ± 0.26) × 106 | 3.28 × 10−7 | 2.34 × 10−4 |
| dCTP | 0.16 ± 0.03 | (1.14 ± 0.28) × 102 | 1.40 × 10−3 | 1.00 |
| dTTP | 0.48 ± 0.05 | (1.23 ± 0.05) × 106 | 3.89 × 10−7 | 2.78 × 10−4 |
| dG-containing substrate* | ||||
| dCTP | 0.34 ± 0.07 | 53 ± 8.4 | 6.42 × 10−3 | 1.00 |
| dTTP | 0.073 ± 0.001 | (4.61 ± 0.56) × 104 | 1.58 × 10−6 | 2.46 × 10−4 |
*The incorporation of dATP and dGTP opposite undamaged dG was barely detectable even at extraordinarily high dNTP concentrations (Fig. S8).