1WCT: A NOVEL CONOTOXIN FROM CONUS TEXTILE WITH UNUSUAL POST-TRANSLATIONAL MODIFICATIONS REDUCES PRESYNAPTIC CALCIUM INFLUX, NMR, 1 STRUCTURE, GLYCOSYLATED PROTEIN

Citation:
Abstract
Cone snails are gastropod mollusks of the genus Conus that live in tropical marine habitats. They are predators that paralyze their prey by injection of venom containing a plethora of small, conformationally constrained peptides (conotoxins). We report the identification, characterization, and structure of a gamma-carboxyglutamic acid-containing peptide, conotoxin epsilon-TxIX, isolated from the venom of the molluscivorous cone snail, Conus textile. The disulfide bonding pattern of the four cysteine residues, an unparalleled degree of posttranslational processing including bromination, hydroxylation, and glycosylation define a family of conotoxins that may target presynaptic Ca2+ channels or act on G protein-coupled presynaptic receptors via another mechanism. This conotoxin selectively reduces neurotransmitter release at an Aplysia cholinergic synapse by reducing the presynaptic influx of Ca2+ in a slow and reversible fashion. The three-dimensional structure, determined by two-dimensional 1H NMR spectroscopy, identifies an electronegative patch created by the side chains of two gamma-carboxyglutamic acid residues that extend outward from a cavernous cleft. The glycosylated threonine and hydroxylated proline enclose a localized hydrophobic region centered on the brominated tryptophan residue within the constrained intercysteine region.
PDB ID: 1WCTDownload
MMDB ID: 51900
PDB Deposition Date: 1998/12/18
Updated in MMDB: 2017/12
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Biological Unit for 1WCT: monomeric; determined by author
Molecular Components in 1WCT
Label Count Molecule
Protein (1 molecule)
1
Omegac-txix
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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