1wz5
From Proteopedia
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Solution structure of Pi1-3p
Overview
Animal toxins are highly reticulated and structured polypeptides that, adopt a limited number of folds. In scorpion species, the most represented, fold is the alpha/beta scaffold in which an helical structure is connected, to an antiparallel beta-sheet by two disulfide bridges. The intimate, relationship existing between peptide reticulation and folding remains, poorly understood. Here, we investigated the role of disulfide bridging on, the 3D structure of HsTx1, a scorpion toxin potently active on Kv1.1 and, Kv1.3 channels. This toxin folds along the classical alpha/beta scaffold, but belongs to a unique family of short-chain, four disulfide-bridged, toxins. Removal of the fourth disulfide bridge of HsTx1 does not affect, its helical structure, whereas its two-stranded beta-sheet is altered from, a twisted to a nontwisted configuration. This structural change in HsTx1, is accompanied by a marked decrease in Kv1.1 and Kv1.3 current blockage, and by alterations in the toxin to channel molecular contacts. In, contrast, a similar removal of the fourth disulfide bridge of Pi1, another, scorpion toxin from the same structural family, has no impact on its 3D, structure, pharmacology, or channel interaction. These data highlight the, importance of disulfide bridging in reaching the correct bioactive, conformation of some toxins.
About this Structure
1WZ5 is a Single protein structure of sequence from Pandinus imperator. Full crystallographic information is available from OCA.
Reference
The impact of the fourth disulfide bridge in scorpion toxins of the alpha-KTx6 subfamily., Carrega L, Mosbah A, Ferrat G, Beeton C, Andreotti N, Mansuelle P, Darbon H, De Waard M, Sabatier JM, Proteins. 2005 Dec 1;61(4):1010-23. PMID:16247791
Page seeded by OCA on Wed Nov 21 05:45:31 2007
