Contryphan


The contryphans are a family of peptides that are active constituents of the potent venom produced by cone snail. The two amino acid cysteine residues in contryphans are linked by a disulfide bond. In addition, contryphans undergo an unusual degree of post-translational modification including
epimerization of leucine and tryptophan, tryptophan bromination, amidation of the C-terminus, and proline hydroxylation. In the broader scheme of genetic conotoxin classification, contryphans are members of "Conotoxin Superfamily O2."

Family members

Contryphan family members include:
PeptideSequenceSpeciesReference
Descontryphan-RCOwEPWC-NH2C. radiatus
Contryphan-RGCOwEPWC-NH2Conus radiatus
Bromocontyphan-RGCOwEPXC-NH2C. radiatus
Contryphan-SmGCOwQPWC-NH2Conus stercusmuscarum
Contryphan-PGCOwDPWC-NH2C. purpurascens
Contryphan-R/TxGCOwEPWC-NH2Conus textile
Contryphan-TxGCOWQPYC-NH2Conus textile
Contryphan-VnGDCPwKPWC-NH2Conus ventricosus
Leu-contryphan-PGCVlLPWC-OHConus purpurascens
Leu-contryphan-TxCVlYPWC-NH2Conus textile
Glaconryphan-MNγSγCPWHPWC-NH2Conus marmoreus

where the sequence abbreviations stand for:
and the remainder of the letters refer to the standard one letter abbreviations for amino acids.

Mechanism of toxicity

The venom of cone snails cause paralysis of their fish prey. The molecular target has not been determined for all contryphan peptides, however it is known that contryphan-Vn is a Ca2+-dependent K+ channel modulator, while glacontryphan-M is a L-type calcium channel blocker.