Table 1. Hydrogen-bond and energetic analysis of ATP binding to the wild type and mutant ε subunit.
| a) | Wild type (kcal/mol) | R103A/R115A (kcal/mol) | ||
| Oα/Oβ | Oβ/Oγ | Oα/Oβ | Oβ/Oγ | |
| h-bonds (protein-ATP) | 9.38 +/- 0.48 | 9.45 +/- 0.09 | 10.4 +/- 0.60 | 9.74 +/- 0.47 |
| h-bonds (2nd α-helix) | 5.27 +/- 0.20 | 4.93 +/- 0.69 | 4.01 +/- 0.18 | 4.05 +/- 0.26 |
| repulsive contacts | 1.96 +/- 0.51 | 1.58 +/- 0.20 | 1.08 +/- 0.51 | 1.54 +/- 0.06 |
| b) | Wild type (kcal/mol) | R103A/R115A (kcal/mol) | ||
| Oα/Oβ | Oβ/Oγ | Oα/Oβ | Oβ/Oγ | |
| EHB (h-bonds (protein-ATP)) | 64.6 +/- 2.4 | 65.2 +/- 0.1 | 73.4 +/- 2.1 | 67.8 +/- 2.9 |
| EHB (h-bonds (2nd α-helix)) | 28.6 +/- 0.7 | 27.0 +/- 2.3 | 26.4 +/- 1.5 | 27.4 +/- 2.3 |
| EHB | 93.2 +/- 0.31 | 92.2 +/- 0.42 | 99.8 +/- 1.8 | 95.2 +/- 2.6 |
a) The number of hydrogen bonds between the protein and ATP, internal protein-protein hydrogen bonds of the C-terminal second α-helix to the rest of the protein and repulsive contacts in the ε subunit from the wild type and the R103A/R115A mutant derived from MD simulations. b) Energetic analysis of the hydrogen bonding network towards ATP and the flexible α-helices. In a) and b) Oα/Oβ and Oβ/Oγ denote the ATP oxygen atoms to which the Mg2+ ion is coordinated during the simulation. Standard deviations were calculated using the averages of the three individual runs.