1hp9: Difference between revisions
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'''kappa-Hefutoxins: a novel Class of Potassium Channel Toxins from Scorpion venom''' | '''kappa-Hefutoxins: a novel Class of Potassium Channel Toxins from Scorpion venom''' | ||
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==About this Structure== | ==About this Structure== | ||
1HP9 is a [[Single protein]] structure | 1HP9 is a [[Single protein]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HP9 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Tytgat, J.]] | [[Category: Tytgat, J.]] | ||
[[Category: Yu, C.]] | [[Category: Yu, C.]] | ||
[[Category: | [[Category: Gating modifier]] | ||
[[Category: | [[Category: Scorpion toxin]] | ||
[[Category: | [[Category: Voltage-gated potassium channel]] | ||
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Revision as of 19:05, 2 May 2008
kappa-Hefutoxins: a novel Class of Potassium Channel Toxins from Scorpion venom
OverviewOverview
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.
About this StructureAbout this Structure
1HP9 is a Single protein structure. Full crystallographic information is available from OCA.
ReferenceReference
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 Page seeded by OCA on Fri May 2 19:05:19 2008