1i25
From Proteopedia
Three dimensional solution structure of huwentoxin-II by 2D 1H-NMR
Structural highlights
FunctionTXH21_CYRSC Lethal neurotoxin that blocks neuromuscular transmission. Acts cooperatively to potentiate the activity of huwentoxin-I. This toxin is active against insects.[1] Publication Abstract from PubMedThe three-dimensional structure of huwentoxin-II (HWTX-II), an insecticidal peptide purified from the venom of spider Selenocosmia huwena with a unique disulfide bond linkage as I-III, II-V, and IV-VI, has been determined using 2D (1)H-NMR. The resulting structure of HWTX-II contains two beta-turns (C4-S7 and K24-W27) and a double-stranded antiparallel beta-sheet (W27-C29 and C34-K36). Although the C-terminal double-stranded beta-sheet cross-linked by two disulfide bonds (II-V and IV-VI in HWTX-II, II-V and III-VI in the ICK molecules) is conserved both in HWTX-II and the ICK molecules, the structure of HWTX-II is unexpected absence of the cystine knot because of its unique disulfide linkage. It suggests that HWTX-II adopts a novel scaffold different from the ICK motif that is adopted by all other spider toxin structures elucidated thus far. Furthermore, the structure of HWTX-II, which conforms to the disulfide-directed beta-hairpin (DDH) motif, not only supports the hypothesis that the ICK is a minor elaboration of the more ancestral DDH motif but also suggests that HWTX-II may have evolved from the same structural ancestor. The structure of spider toxin huwentoxin-II with unique disulfide linkage: evidence for structural evolution.,Shu Q, Lu SY, Gu XC, Liang SP Protein Sci. 2002 Feb;11(2):245-52. PMID:11790834[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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