Atomic naming in PDB consists of 4 character field: atomic symbol (2 char), remoteness indicator (1 char), branch designator (1 char).
Remoteness indcator uses Greek letter distance abbreviation. In order of increasing distance, these are A for alpha, B for beta, G for gamma, D for delta, E for epsilon, Z for zeta, and H for eta.
Branch designator: digit designating the branch direction; left blank if the sidechain is unbranched.
Color scheme: Red=Oxygen; Gray=Carbon; Blue=Nitrogen; Cyan=Hydrogen; Yellow=Sulphur
Tryptophan
| AA | W |
| Code | Trp |
| Fullname | Tryptophan |
| Side chain type | hydrophobic |
| Mass | 204.23 |
| pI | 5.89 |
| pK1(a-COOH) | 2.46 |
| pK2(a-+NH3) | 9.41 |
| pKr (R) | |
| hydrophobic | X |
| positive | - |
| negative | - |
| polar | X |
| charged | - |
| small | - |
| tiny | - |
| aromatic | X |
| aliphatic | - |
| van der Waals volume | 163
|
| Remarks
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