View source for 1hp9

[[Image:1hp9.jpg|left|200px]]

 {{Structure
|PDB= 1hp9 |SIZE=350|CAPTION= <scene name='initialview01'>1hp9</scene>
|SITE= 
|LIGAND= 
|ACTIVITY= 
|GENE= 
|DOMAIN=
|RELATEDENTRY=
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1hp9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1hp9 OCA], [http://www.ebi.ac.uk/pdbsum/1hp9 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1hp9 RCSB]</span>
}}

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


==Overview==
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 Structure==
1HP9 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HP9 OCA]. 

==Reference==
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:[http://www.ncbi.nlm.nih.gov/pubmed/12034709 12034709]
[[Category: Single protein]]
[[Category: Bowie, J H.]]
[[Category: Cheng, B.]]
[[Category: Chia, C S.Brian.]]
[[Category: Gopalakrishnakone, P.]]
[[Category: Huys, I.]]
[[Category: Kini, R M.]]
[[Category: Kumar, T K.S.]]
[[Category: Ranganathan, S.]]
[[Category: Sasaki, T.]]
[[Category: Sato, K.]]
[[Category: Sivaraja, V.]]
[[Category: Srinivasan, K N.]]
[[Category: Tytgat, J.]]
[[Category: Yu, C.]]
[[Category: gating modifier]]
[[Category: scorpion toxin]]
[[Category: voltage-gated potassium channel]]

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