Table 2.
Steady-state kinetic parameters for hpol κ19-526 catalysis on G4 DNA and non-G4 DNA substrates prepared in KCl
kcat (min−1) | KM,dNTP (μM) | kcat/KM,dNTP (min−1 μM−1) | Relative activitya | |
---|---|---|---|---|
13/42-mer: dCMP insertion opposite template dG −10 nt from G22 | ||||
non-G4 DNA | 7.5 ± 0.9 | 13 ± 3 | 0.58 | - |
G4 DNA | 1.7 ± 0.2 | 30 ± 9 | 0.06 | 10.4 ± 1.4% |
14/42-mer: dGMP insertion opposite template dC −9 nt from G22 | ||||
non-G4 DNA | 3.7 ± 1.0 | 26 ± 3 | 0.15 | - |
G4 DNA | 1.2 ± 0.8 | 169 ± 37 | 0.007 | 5.0 ± 1.0% |
18/42-mer: dAMP insertion opposite template dT −5 nt from G22 | ||||
non-G4 DNA | 8.9 ± 4.1 | 13 ± 2 | 0.65 | - |
G4 DNA | 3.8 ± 0.8 | 85 ± 29 | 0.05 | 7.5 ± 2.1% |
19/42-mer: dCMP insertion opposite template dG −4 nt from G22 | ||||
non-G4 DNA | 9.0 ± 3.5 | 20 ± 1 | 0.45 | - |
G4 DNA | 2.3 ± 0.3 | 25 ± 8 | 0.10 | 22.8 ± 2.4% |
20/42-mer: dGMP insertion opposite template dC −3 nt from G22 | ||||
non-G4 DNA | 5.1 ± 0.3 | 4.9 ± 1.5 | 1.10 | - |
G4 DNA | 4.4 ± 1.0 | 4.1 ± 0.7 | 1.13 | 103 ± 18% |
21/42-mer: dCMP insertion opposite template dG −2 nt from G22 | ||||
non-G4 DNA | 8.6 ± 1.8 | 28 ± 1 | 0.31 | - |
G4 DNA | 7.9 ± 1.9 | 14 ± 2 | 0.57 | 188 ± 25% |
22/42-mer: dAMP insertion opposite template dT −1 nt from G22 | ||||
non-G4 DNA | 7.3 ± 1.5 | 4.4 ± 0.9 | 1.67 | - |
G4 DNA | 2.6 ± 0.4 | 11 ± 1 | 0.24 | 14.6 ± 3.1% |
23/42-mer: dCMP insertion opposite G22 | ||||
non-G4 DNA | 6.4 ± 0.3 | 6.1 ± 0.4 | 1.06 | - |
G4 DNA | 0.21 ± 0.03 | 26 ± 3 | 0.0081 | 0.76 ± 0.11% |
Relative activity was calculated as [(kcat/Km,dNTP)G4 DNA/(kcat/Km,dNTP)non-G4 DNA] × 100 for three to four individual sets of experiments. For determination of kcat and Km,dNTP, graphs of the initial rate of product formation versus dNTP concentration were plotted using non-linear regression analysis (one-site hyperbolic fit) in the GraphPad Prism program. The mean and standard deviation of three to four individual sets of experiments is reported for each kcat and Km,dNTP value.