Table 2.
Ensemble-averaged structural properties of WT DHFR and I14X mutants with the Met20 loop in a closed conformation at 25 °C in the ground and transition states
Standard deviations are shown in parentheses. The ensemble-averaged data were obtained from 250-ps simulations of the GS and TS. The position of the TS along the reaction coordinate was determined from the position of the maximum PMF value.
| WT |
I14V |
I14A |
I14G |
|||||
|---|---|---|---|---|---|---|---|---|
| GS | TS | GS | TS | GS | TS | GS | TS | |
| ζasym (Å)a | −1.73 (0.28) | −0.09 (0.01) | −1.98 (0.29) | −0.09 (0.01) | −1.98 (0.33) | −0.10 (0.01) | −1.88 (0.24) | −0.09 (0.01) |
| C4N–C6 (DAD) (Å) | 3.82 (0.21) | 2.64 (0.07) | 4.02 (0.21) | 2.63 (0.07) | 4.00 (0.21) | 2.65 (0.07) | 3.84 (0.23) | 2.65 (0.07) |
| C4N–H4N–C6 (∡D-H-A) (°) | 145.09 (15.33) | 157.46 (7.69) | 140.27 (13.87) | 155.09 (7.97) | 133.77 (15.58) | 157.20 (7.94) | 142.15 (17.68) | 156.70 (7.75) |
| N5–S(Met20) (Å) | 3.79 (0.34) | 3.70 (0.37) | 3.90 (0.33) | 3.58 (0.29) | 3.82 (0.28) | 4.16 (0.44) | 4.37 (0.56) | 3.78 (0.44) |
| N7N–S(Met20) (Å) | 3.67 (0.33) | 3.72 (0.33) | 3.60 (0.26) | 3.71 (0.31) | 4.09 (0.45) | 4.45 (0.44) | 4.66 (0.73) | 4.10 (0.61) |
| N7N–O(Ala7) (Å) | 2.78 (0.14) | 2.82 (0.13) | 2.88 (0.16) | 2.90 (0.14) | 2.84 (0.13) | 2.84 (0.13) | 2.91 (0.18) | 2.87 (0.14) |
| N7N–O(Ile14) (Å) | 3.02 (0.24) | 2.93 (0.22) | 3.07 (0.22) | 3.13 (0.25) | 3.20 (0.32) | 3.15 (0.33) | 3.21 (0.37) | 2.93 (0.18) |
| O7N–N(Ala7) (Å) | 3.19 (0.23) | 2.90 (0.11) | 3.41 (0.29) | 2.92 (0.12) | 3.15 (0.18) | 2.99 (0.14) | 3.30 (0.25) | 2.99 (0.14) |
| N3–Oδ2(Asp27) (Å) | 2.73 (0.17) | 2.74 (0.17) | 2.96 (0.26) | 2.86 (0.18) | 2.87 (0.20) | 2.85 (0.16) | 2.91 (0.22) | 2.84 (0.17) |
| NA2–Oδ1(Asp27) (Å) | 2.72 (0.11) | 2.75 (0.12) | 2.79 (0.12) | 2.81 (0.12) | 2.78 (0.11) | 2.78 (0.11) | 2.78 (0.11) | 2.80 (0.12) |
a Determined from the stationary points along the PMF profile.