1hp9

kappa-Hefutoxins: a novel Class of Potassium Channel Toxins from Scorpion venom

spinqualitylabelsall models 1hp9, 1 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1hp9 is a 1 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed An important and exciting challenge in the postgenomic era is to understand the functions of newly discovered proteins based on their structures. The main thrust is to find the common structural motifs that contribute to specific functions. Using this premise, here we report the purification, solution NMR, and functional characterization of a novel class of weak potassium channel toxins from the venom of the scorpion Heterometrus fulvipes. These toxins, kappa-hefutoxin1 and kappa-hefutoxin2, exhibit no homology to any known toxins. NMR studies indicate that kappa-hefutoxin1 adopts a unique three-dimensional fold of two parallel helices linked by two disulfide bridges without any beta-sheets. Based on the presence of the functional diad (Tyr(5)/Lys(19)) at a distance (6.0 +/- 1.0 A) comparable with other potassium channel toxins, we hypothesized its function as a potassium channel toxin. kappa-Hefutoxin 1 not only blocks the voltage-gated K(+)-channels, Kv1.3 and Kv1.2, but also slows the activation kinetics of Kv1.3 currents, a novel feature of kappa-hefutoxin 1, unlike other scorpion toxins, which are considered solely pore blockers. Alanine mutants (Y5A, K19A, and Y5A/K19A) failed to block the channels, indicating the importance of the functional diad. kappa-Hefutoxin1, a novel toxin from the scorpion Heterometrus fulvipes with unique structure and function. Importance of the functional diad in potassium channel selectivity.,Srinivasan KN, Sivaraja V, Huys I, Sasaki T, Cheng B, Kumar TK, Sato K, Tytgat J, Yu C, San BC, Ranganathan S, Bowie HJ, Kini RM, Gopalakrishnakone P J Biol Chem. 2002 Aug 16;277(33):30040-7. Epub 2002 May 28. PMID:12034709 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Potassium channel toxin

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