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Solution NMR Structure of Conotoxin GXIA from Conus geographus
Structural highlights
FunctionI3B1_CONGE May embed in the membrane and bind to the voltage sensor domain of a ion channel (PubMed:24662800). Does not induce paralysis when injected in fish, leading to the hypothesis that it may be part of the sedative nirvana cabal (Probable).[1] [2] Publication Abstract from PubMedConotoxins are disulfide-rich peptides found in the venom of cone snails. Due to their exquisite potency and high selectivity for a wide range of voltage and ligand gated ion channels they are attractive drug leads in neuropharmacology. Recently, cone snails were found to have the capability to rapidly switch between venom types with different proteome profiles in response to predatory or defensive stimuli. A novel conotoxin, GXIA (original name G117), belonging to the I(3)-subfamily was identified as the major component of the predatory venom of piscivorous Conus geographus. Using 2D solution NMR spectroscopy techniques, we resolved the 3D structure for GXIA, the first structure reported for the I(3)-subfamily and framework XI family. The 32 amino acid peptide is comprised of eight cysteine residues with the resultant disulfide connectivity forming an ICK+1 motif. With a triple stranded beta-sheet, the GXIA backbone shows striking similarity to several tarantula toxins targeting the voltage sensor of voltage gated potassium and sodium channels. Supported by an amphipathic surface, the structural evidence suggests that GXIA is able to embed in the membrane and bind to the voltage sensor domain of a putative ion channel target. Chemical Synthesis and NMR Solution Structure of Conotoxin GXIA from Conus geographus.,Armstrong DA, Jin AH, Braga Emidio N, Lewis RJ, Alewood PF, Rosengren KJ Mar Drugs. 2021 Jan 26;19(2):60. doi: 10.3390/md19020060. PMID:33530397[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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