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2h9x
From Proteopedia
NMR structure for the CgNa toxin from the sea anemone Condylactis gigantea
Overview
CgNa (Condylactis gigantea neurotoxin) is a 47-amino-acid- residue toxin from the giant Caribbean sea anemone Condylactis gigantea. The structure of CgNa, which was solved by 1H-NMR spectroscopy, is somewhat atypical and displays significant homology with both type I and II anemone toxins. CgNa also displays a considerable number of exceptions to the canonical structural elements that are thought to be essential for the activity of this group of toxins. Furthermore, unique residues in CgNa define a characteristic structure with strong negatively charged surface patches. These patches disrupt a surface-exposed cluster of hydrophobic residues present in all anemone-derived toxins described to date. A thorough characterization by patch-clamp analysis using rat DRG (dorsal root ganglion) neurons indicated that CgNa preferentially binds to TTX-S (tetrodotoxin-sensitive) voltage-gated sodium channels in the resting state. This association increased the inactivation time constant and the rate of recovery from inactivation, inducing a significant shift in the steady state of inactivation curve to the left. The specific structural features of CgNa may explain its weaker inhibitory capacity when compared with the other type I and II anemone toxins.
About this Structure
2H9X is a Single protein structure of sequence from Condylactis gigantea. Full crystallographic information is available from OCA.
Reference
CgNa, a type I toxin from the giant Caribbean sea anemone Condylactis gigantea shows structural similarities to both type I and II toxins, as well as distinctive structural and functional properties(1)., Salceda E, Perez-Castells J, Lopez-Mendez B, Garateix A, Salazar H, Lopez O, Aneiros A, Standker L, Beress L, Forssmann WG, Soto E, Jimenez-Barbero J, Gimenez-Gallego G, Biochem J. 2007 Aug 15;406(1):67-76. PMID:17506725 Page seeded by OCA on Sun May 4 06:02:15 2008
