Proteomic Analysis of the Predatory Venom of Conus striatus Reveals Novel and Population-Specific κA-Conotoxin SIVC

Abstract

Animal venoms are a rich source of pharmacological compounds with ecological and evolutionary significance, as well as with therapeutic and biotechnological potentials. Among the most promising venomous animals, cone snails produce potent neurotoxic venom to facilitate prey capture and defend against aggressors. Conus striatus, one of the largest piscivorous species, is widely distributed, from east African coasts to remote Polynesian Islands. In this study, we investigated potential intraspecific differences in venom composition between distinct geographical populations from Mayotte Island (Indian Ocean) and Australia (Pacific Ocean). Significant variations were noted among the most abundant components, namely the κA-conotoxins, which contain three disulfide bridges and complex glycosylations. The amino acid sequence of a novel κA-conotoxin SIVC, including its N-terminal acetylated variant, was deciphered using tandem mass spectrometry (MS/MS). In addition, the glycosylation pattern was found to be consisting of two HexNAc and four Hex for the Mayotte population, which diverge from the previously characterized two HexNAc and three Hex combinations for this species, collected elsewhere. Whereas the biological and ecological roles of these modifications remain to be investigated, population-specific glycosylation patterns provide, for the first time, a new level of intraspecific variations in cone snail venoms.

Predatory and Defensive Strategies in Cone Snails

“…Exhaustive investigation of the predatory venom of Pionoconus consors also revealed the importance of κA-conotoxins, with the abundant injection of κA-CcTx and the sequencing of a series of CcTx variants [ 24 , 37 , 50 ]. Although not confirmed, the major compounds found in the predatory venom of another Pionoconus species, Pionoconus magus , were determined within the mass range of κA-conotoxins [ 40 ]. More recently, these κA-conotoxins were identified abundantly in both predatory and defensive venom of Pionoconus striatus [ 32 ] and in the predatory venom of Pionoconus catus [ 25 ].…”

“…These α-conotoxins, although not systematically injected, are especially represented in the Pionoconus and Chelyconus clades, and less in the Gastridium clades [ 2 ]. For instance, some of the α-conotoxins identified in the Pionoconus clade include α-SI ( Pionoconus striatus ) [ 23 , 32 , 39 ], α-CnIB ( Pionoconus consors ) [ 37 , 51 ], α-MI ( Pionoconus magus ) [ 40 ], and α-CIB ( Pionoconus catus ) [ 25 ]. Similarly, α-PIB ( Chelyconus purpurascens ) and α-EIIA ( Chelyconus ermineus ) [ 52 ] are found in the Chelyconus clade.…”