Contryphans from Conus textile venom ducts

Contryphans an unusual Conus peptides which contain a distinctive post-translational modification, D-tryptophan or D-leucine. cDNA clones encoding new contryphans from the mollusc-hunting cone snail Conus textile were identified and the inferred mature peptides were synthesized: contryphan-Tx (Glp-Cys-Hyp-D-Trp-Gln-Pro-Tyr-Cys-NH2), Leu-contryphan-Tx (Cys-Val-D-Leu-Tyr-Pro-Trp-Cys-NH2) and contryphan R/Tx which is identical to contryphan-R [Jimenez et al., 1996. Contryphan is a D-tryptophan containing Conus peptide. J. Biol. Chem. 281, 78002-28005], Leu-contryphan-Tx exhibits a single peak, but contryphan-Tx shows two peaks under reverse-phase high-performance liquid chromatography conditions. Ultraviolet resonance Raman spectroscopy demonstrates a difference in the D-tryptophan dihedral angle for the two contryphan-Tx equilibrium conformers. Both the sequences and in vivo effects of all contryphans isolated suggest that there are two major branches of the contryphan family. (C) 2001 Elsevier Science Ltd. All rights reserved.