Contryphan

Contryphan

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Contryphan

Conus textile, which produces contryphans

The contryphans (conus + tryptophan) are a family of peptides (, ) which are active constituents of venom produced by cone snail (genus conus). 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.^[1]

Family members
Mechanism of toxicity
References
See also
External links

Family members

Contryphan family members include:

Peptide	Sequence	Species	Reference
Des(Gly1)contryphan-R	COwEPWC-NH2	C. radiatus	^[2]
Contryphan-R	GCOwEPWC-NH2	C. radiatus	^[2]
Bromocontyphan-R	GCOwEPXC-NH2	C. radiatus	^[3]
Contryphan-Sm	GCOwQPWC-NH2	C. stercusmuscarum	^[4]
Contryphan-P	GCOwDPWC-NH₂	C. purpurascens	^[4]
Contryphan-R/Tx	GCOwEPWC-NH2	C. textile	^[4]
Contryphan-Tx	GCOWQPYC-NH2	C. textile	^[4]
Contryphan-Vn	GDCPwKPWC-NH₂	C. ventricosus	^[5]
Leu-contryphan-P	GCVlLPWC-OH	C. purpurascens	^[6]
Leu-contryphan-Tx	CVlYPWC-NH₂	C. textile	^[4]
Glaconryphan-M	N?S?CPWHPWC-NH₂	C. marmoreus	^[1]

where the sequence abbreviations stand for:

O = 4-trans-hydroxyproline,
l = D-leucine, L = L-leucine,
w = D-tryptophan, W = L-tryptophan,
? = gamma-carboxyglutamic acid,
NH₂ = C-terminal amidation

and the remainder of the letters refer to the standard one letter abbreviations for amino acids.

Mechanism of toxicity

NMR structure (<!-- PDB -->) of Contryphan-Vn. The peptide backbone is depicted by a curved cartoon diagram while the amino acid side chains are represented by capped sticks. Carbon atoms are colored grey, nitrogen blue, oxygen red, and sulfur atoms yellow.

NMR structure () of Contryphan-Vn. The peptide backbone is depicted by a curved cartoon diagram while the amino acid side chains are represented by capped sticks. Carbon atoms are colored grey, nitrogen blue, oxygen red, and sulfur atoms yellow.

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, ^[5] while glacontryphan-M is a L-type calcium channel blocker.^[1]