Isolation and characterization of novel conopeptides from Conus dalli.

摘要

Conus dalli is a cone snail species that preys upon mollusks (molluscivorous) and it belongs to the same clade as the better studied Conus textile. They have different biogeographical distribution: C. dalli is restricted to the Panamic area; whereas C. textile is a widespread species found from the Red Sea to Hawaii. The venom of C. textile is an extremely complex mixture of conopeptides characterized for their very high content of modified amino acids; particularly, for their high content of gamma-carboxy glutamate (Gla). Therefore, it is expected that the venom of C. dalli is equally complex and it might provide us with a library of novel conopeptides. We have collected 6 specimens of C. dalli from the Pacific coast of Panama. Their venom ducts were dissected and 40 mg of crude venom were extracted.; Venom was separated using SE-HPLC and RP-HPLC and several single-component fractions with unique molecular weights have been found. 1D and 2D NMR methods in conjunction with mass spectrometry techniques have been applied to the main components of the venom. Three novel conopeptides have been isolated and characterized; dal_C1011h, dal_C0910, and dal_C0805g. dal_C1011h is a 27-residue hydrophobic conotoxin that belongs to O-superfamily, dal_C0910 is a 16-residue conotoxin that belongs to M-superfamily, and dal_C0805g is a 12-residue linear conopeptide the belong to the Conorfamide family. The details on the characterization of these conopeptides along with a comparison with previous data obtained from C. textile are presented.