Table 1.
Main-chain hydrogen bonds in the X-ray, NMR, and simulated structures of toxin α determined using the DSSP program (Kabsch and Sander 1983)
| Residue | Hydrogen bond | |||
| NH | CO | X-ray | NMR(%) | MD(%) |
| X1 | ||||
| Q2* | D57.od1 | — | D57.od1 | |
| C3* | K15 | X | X | 97 |
| H4* | K58 | R60.od1 | X | 44 |
| N5* | T13 | X | X | 72 |
| Q6* | T13 | Q6.oe1 | — | — |
| Q7 | ||||
| S8 | 136 | X | 88 | — |
| S9 | ||||
| Q10* | Q7 | X | X | 36 |
| P11 | ||||
| P12 | ||||
| T13* | P11 | Q6.oe1 | — | 95 |
| T14 | ||||
| K15* | C3 | X | X | X |
| T16 | ||||
| C17* | X1 | X | X | 79 |
| P18 | ||||
| G19 | C17 | — | X | X |
| Q20 | C17 | X | X | — |
| T21 | ||||
| N22* | ||||
| C23* | C54 | X | X | 64 |
| Y24* | G39 | X | X | X |
| K25* | N52 | X | X | X |
| K26* | Q37 | X | X | X |
| V27* | K50 | X | X | X |
| W28* | I35 | X | X | X |
| R29* | G48 | — | 38 | — |
| D30* | G33 | X | X | X |
| H31 | ||||
| R32 | ||||
| G33 | D30 | X | ||
| T34* | ||||
| I35* | W28 | X | X | X |
| I36* | T34 | S8.og | — | 41 |
| Q37* | K26 | X | X | X |
| R38* | Q6 | — | — | 28 |
| G39* | Y24 | X | X | 95 |
| C40 | ||||
| G41* | N22 | X | X | X |
| C42 | ||||
| P43 | ||||
| T44 | ||||
| V45* | ||||
| K46* | T44 | 36 | ||
| P47 | ||||
| G48 | K46 | 50 | ||
| I49* | K46 | X | X | 82 |
| K50* | V27 | X | X | 95 |
| N52* | K25 | X | X | X |
| C53 | ||||
| C54* | C23 | X | X | X |
| T55 | ||||
| T56* | ||||
| D57 | ||||
| K58* | Q2 | X | 50 | 97 |
| C59 | T56 | X | 75 | 51 |
| N60* | N60.og | 46 | ||
| N61* | C59.o | C59.o | ||
Residue names with an asterisk are those for which the amide proton is found to be protected from the exchange by NMR. “X” indicates that the hydrogen bond is present in the X-ray structure, or at 100% present in NMR and simulated structures. Percentage of structures presenting the hydrogen bond is indicated for NMR and simulated structures when different from 100%. Identified side-chain acceptors are also indicated.