Table 5. Steady-State Kinetic Parameters for dNTP Incorporation Opposite G, O6-MeG, and N2-EtG by Wild-Type and Variant hPols ι(1-445) in the Presence of 0.15 mM Mn2+.
template | pol ι(1–445) | dNTP | Km (μM) | kcat (s–1) | kcat/Km (s–1 mM–1) | finsa | relative efficiencyb |
---|---|---|---|---|---|---|---|
G | wild-type | C | 1.5 ± 0.1 | 0.11 ± 0.002 | 73 | 1 | 1 |
T | 3.3 ± 0.2 | 0.094 ± 0.002 | 28 | 0.38 | |||
Δ1–25 | C | 0.52 ± 0.05 | 0.036 ± 0.0007 | 72 | 1 | 0.99 | |
T | 1.2 ± 0.1 | 0.055 ± 0.001 | 46 | 0.64 | |||
ΔD17 | C | 1.4 ± 0.003 | 0.12 ± 0.003 | 86 | 1 | 1.2 | |
T | 3.6 ± 0.2 | 0.12 ± 0.002 | 33 | 0.38 | |||
R96G | C | 11 ± 1 | 0.028 ± 0.001 | 2.5 | 1 | 0.034 | |
T | 11 ± 1 | 0.0075 ± 0.0003 | 0.68 | 0.27 | |||
I261M | C | 1.3 ± 0.08 | 0.068 ± 0.0009 | 52 | 1 | 0.71 | |
T | 3.0 ± 0.2 | 0.068 ± 0.001 | 23 | 0.44 | |||
E276K | C | 1.4 ± 0.08 | 0.051 ± 0.0006 | 36 | 1 | 0.49 | |
T | 3.4 ± 0.1 | 0.047 ± 0.0005 | 14 | 0.39 | |||
Y374N | C | 2.6 ± 0.2 | 0.14 ± 0.003 | 54 | 1 | 0.74 | |
T | 3.8 ± 0.2 | 0.095 ± 0.001 | 25 | 0.46 | |||
O6-MeG | wild-type | C | 3.9 ± 0.1 | 0.10 ± 0.001 | 26 | 1 | 1 |
T | 3.2 ± 0.2 | 0.069 ± 0.001 | 22 | 0.85 | |||
Δ1–25 | C | 1.6 ± 0.09 | 0.039 ± 0.0005 | 24 | 1 | 0.93 | |
T | 1.4 ± 0.2 | 0.027 ± 0.001 | 19 | 0.79 | |||
ΔD17 | C | 3.8 ± 0.2 | 0.18 ± 0.003 | 47 | 1 | 1.8 | |
T | 2.5 ± 0.4 | 0.087 ± 0.003 | 35 | 0.74 | |||
R96G | C | 12 ± 3 | 0.019 ± 0.002 | 1.6 | 1 | 0.062 | |
T | 4.3 ± 0.6 | 0.0073 ± 0.0003 | 1.7 | 1.1 | |||
I261M | C | 2.3 ± 0.1 | 0.075 ± 0.001 | 33 | 1 | 1.3 | |
T | 4.0 ± 0.5 | 0.036 ± 0.001 | 9.0 | 0.27 | |||
E276K | C | 2.5 ± 0.1 | 0.044 ± 0.0006 | 18 | 1 | 0.69 | |
T | 3.2 ± 0.4 | 0.038 ± 0.001 | 12 | 0.67 | |||
Y374N | C | 3.7 ± 0.3 | 0.077 ± 0.001 | 21 | 1 | 0.81 | |
T | 2.0 ± 0.3 | 0.050 ± 0.002 | 25 | 1.2 | |||
N2-EtG | wild-type | C | 27 ± 2 | 0.034 ± 0.001 | 1.3 | 1 | 1 |
T | 80 ± 5 | 0.045 ± 0.001 | 0.56 | 0.44 | |||
Δ1–25 | C | 7.5 ± 1.1 | 0.011 ± 0.001 | 1.5 | 1 | 1.2 | |
T | 29 ± 2 | 0.018 ± 0.0005 | 0.62 | 0.42 | |||
ΔD17 | C | 13 ± 1 | 0.025 ± 0.001 | 1.9 | 1 | 1.5 | |
T | 93 ± 12 | 0.044 ± 0.003 | 0.47 | 0.24 | |||
R96G | C | 3.7 ± 0.1 | 0.045 ± 0.0004 | 12 | 1 | 9.2 | |
T | 26 ± 9 | 0.0058 ± 0.0008 | 0.22 | 0.018 | |||
I261M | C | 16 ± 2 | 0.023 ± 0.001 | 1.4 | 1 | 1.1 | |
T | 87 ± 11 | 0.042 ± 0.002 | 0.48 | 0.34 | |||
E276K | C | 20 ± 5 | 0.018 ± 0.002 | 0.90 | 1 | 0.69 | |
T | 92 ± 13 | 0.042 ± 0.003 | 0.46 | 0.51 | |||
Y374N | C | 33 ± 3 | 0.039 ± 0.02 | 1.2 | 1 | 0.92 | |
T | 82 ± 4 | 0.035 ± 0.001 | 0.43 | 0.36 |
Misinsertion frequency, calculated by dividing kcat/Km for each dNTP incorporation by the kcat/Km for dCTP incorporation opposite template base. All values are presented to two significant digits.
Relative efficiency, calculated by dividing kcat/Km of each pol ι(1–445) for dCTP incorporation opposite template base by kcat/Km of wild-type pol ι(1–445) for dCTP incorporation opposite template base.