1Y29

Three dimensional solution structure of huwentoxin-x by 2D 1H-NMR

1Y29 の概要

• エントリーDOI: 10.2210/pdb1y29/pdb
• 分子名称: huwentoxin-x (1 entity in total)
• 機能のキーワード: a double-stranded beta-sheet, ick, knottin, toxin
• 細胞内の位置: Secreted: P68424
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 2942.57

構造登録者

Liu, Z.,Liang, S. (登録日: 2004-11-22, 公開日: 2004-12-07, 最終更新日: 2024-10-30)

主引用文献

Liu, Z.,Dai, J.,Dai, L.,Deng, M.,Hu, Z.,Hu, W.,Liang, S.
Function and solution structure of Huwentoxin-X, a specific blocker of N-type calcium channels, from the Chinese bird spider Ornithoctonus huwena
J.Biol.Chem., 281:8628-8635, 2006

PubMed Abstract: Huwentoxin-X (HWTX-X) is a novel peptide toxin, purified from the venom of the spider Ornithoctonus huwena. It comprises 28 amino acid residues including six cysteine residues as disulfide bridges linked in the pattern of I-IV, II-V, and III-VI. Its cDNA, determined by rapid amplification of 3' and 5' cDNA ends, encodes a 65-residue prepropeptide. HWTX-X shares low sequence homology with omega-conotoxins GVIA and MVIIA, two well known blockers of N-type Ca2+ channels. Nevertheless, whole cell studies indicate that it can block N-type Ca2+ channels in rat dorsal root ganglion cells (IC50 40 nm) and the blockage by HWTX-X is completely reversible. The rank order of specificity for N-type Ca2+ channels is GVIA approximately HWTX-X > MVIIA. In contrast to GVIA and MVIIA, HWTX-X had no detectable effect on the twitch response of rat vas deferens to low frequency electrical stimulation, indicating that HWTX-X has different selectivity for isoforms of N-type Ca2+ channels, compared with GVIA or MVIIA. A comparison of the structures of HWTX-X and GVIA reveals that they not only adopt a common structural motif (inhibitor cystine knot), but also have a similar functional motif, a binding surface formed by the critical residue Tyr, and several basic residues. However, the dissimilarities of their binding surfaces provide some insights into their different selectivities for isoforms of N-type Ca2+ channels.

PubMed: 16439354
DOI: 10.1074/jbc.M513542200

実験手法

SOLUTION NMR