Table 2. Conotoxin cysteine frameworks.
| Cysteine frameworka | Cysteine patternb | # Cysteines | # Mature proteins | Gene superfamilies |
|---|---|---|---|---|
| I | CC-C-C | 4 | 293 | A, M, O1, T |
| II | CCC-C-C-C | 6 | 3 | A, M |
| III | CC-C-C-CC | 6 | 299 | M |
| IV | CC-C-C-C-C | 6 | 51 | A, M |
| V | CC-CC | 4 | 128 | T |
| VI/VII | C-C-CC-C-C | 6 | 517 | H, I1, I3, M, O1, O2, O3 |
| VIII | C-C-C-C-C-C-C-C-C-C | 10 | 11 | B2, S |
| IX | C-C-C-C-C-C | 6 | 29 | M, P |
| X | CC-C[PO]C | 4 | 11 | M, T |
| XI | C-C-CC-CC-C-C | 8 | 89 | I1, I2, I3 |
| XII | C-C-C-C-CC-C-C | 8 | 49 | I2, O1 |
| XIII | C-C-C-CC-C-C-C | 8 | 2 | G |
| XIV | C-C-C-C | 4 | 56 | A, I2, J, L, M, O1, O2 |
| XV | C-C-CC-C-C-C-C | 8 | 23 | D, N, O2, V |
| XVI | C-C-CC | 4 | 7 | M, T |
| XVII | C-C-CC-C-CC-C | 8 | 1 | Y |
| XVIII | C-C-CC-CC | 6 | 2 | |
| XIX | C-C-C-CCC-C-C-C-C | 10 | 2 | |
| XX | C-CC-C-CC-C-C-C-C | 10 | 21 | D |
| XXI | CC-C-C-C-CC-C-C-C | 10 | 1 | |
| XXII | C-C-C-C-C-C-C-C | 8 | 8 | E |
| XXIII | C-C-C-CC-C | 6 | 6 | K |
| XXIV | C-CC-C | 4 | 1 | B3 |
| XXV | C-C-C-C-CC | 6 | 1 | |
| XXVI | C-C-C-C-CC-CC | 8 | 1 |
a
The conotoxin cysteine frameworks are defined according to a specific pattern of cysteines in the mature peptide region of conopeptide precursors. The founding reference for each cysteine framework can be found on the ConoServer website (http://www.conoserver.org), which provides updates to this table and additional statistics.
b
Hyphens separating the cysteines (C) stand for a protein segments of one or more amino acids. “[PO]” indicate a position that could be occupied by a proline (P) or hydroxy-proline (O). “.” represents a single position that could be occupied by any amino acid.