TABLE 3.
Summary of total interactions of each NTP with EV-D68-3Dpol and their stability enhancement effectsa
| Sample (PDB accession no.) | No. of hydrogen bonds | No. of salt bridges | Total no. of interactions | Distance to Asp234/Asp238b (Å) | Stability enhancementc |
|---|---|---|---|---|---|
| GTP-3Dpol-EV-D68 | 8 | 3 | 11 | 2.42 | ++++ |
| GTP-3Dpol-EV71 (3N6M) | 8 | 2 | 10 | 2.67 | ++++ |
| GTP-3Dpol-polio (1RA7) | 6 | 3 | 9 | 2.76 | ++++ |
| UTP-3Dpol-polio (2IM2) | 6 | 2 | 8 | 2.49 | +++ |
| ATP-3Dpol-polio (2ILY) | 6 | 3 | 9 | 2.99 | ++ |
| CTP-3Dpol-polio (2IM0) | 5 | 2 | 7 | 2.83 | + |
a
Cutoff distance, ≤3.35 Å.
b
Asp234 is according to EV-D68 numbering, and Asp238 is according to EV71 numbering.
c
Stability enhancement was measured by the unfolding temperature differences between NTP-bound EV-D68-3Dpol and apoenzyme. The number of plus signs indicates the extent of protection conferred by each NTP.