1C49

STRUCTURAL AND FUNCTIONAL DIFFERENCES OF TWO TOXINS FROM THE SCORPION PANDINUS IMPERATOR

1C49 の概要

• エントリーDOI: 10.2210/pdb1c49/pdb
• NMR情報: BMRB: 4760
• 分子名称: TOXIN K-BETA (1 entity in total)
• 機能のキーワード: scorpion toxin, potassium channels blockers, alpha-k toxin family, neurotoxin, nmr solution structure, toxin
• 由来する生物種: Pandinus imperator (emperor scorpion)
• 細胞内の位置: Secreted: P55928
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 4080.82

構造登録者

Klenk, K.C.,Tenenholz, T.C.,Matteson, D.R.,Rogowski, R.S.,Blaustein, M.P.,Weber, D.J. (登録日: 1999-08-17, 公開日: 2000-03-22, 最終更新日: 2024-10-30)

主引用文献

Klenk, K.C.,Tenenholz, T.C.,Matteson, D.R.,Rogowski, R.S.,Blaustein, M.P.,Weber, D.J.
Structural and functional differences of two toxins from the scorpion Pandinus imperator.
Proteins, 38:441-449, 2000

PubMed Abstract: The Pandinotoxins, PiTX-K alpha and PiTX-K beta, are members of the Charybdotoxin family of scorpion toxins that can be used to characterize K+ channels. PiTX-K alpha differs from PiTX-K beta, another peptide from Pandinus imperator, by one residue (P10E). When the two toxins are compared in a physiological assay, the affinity of PiTX-K beta for voltage-gated, rapidly inactivating K+ channels in dorsal root ganglia (DRG) neurons is 800-fold lower than that of PiTX-K alpha (K alpha-IC50 = 8.0 nM versus K beta-IC50 = 6,500 nM). To understand this difference, the three-dimensional structure of PiTX-K beta was determined by nuclear magnetic resonance (NMR) spectroscopy and compared to that of PiTX-K alpha. This comparison shows that structural differences between the two toxins occur at a residue that is critical for blocking K+ channels (K27) as well as at the site of the natural mutation (P10E). In PiTX-K beta, the negatively charged carboxylate oxygen of E10 can approach the positive charge of K27 and presumably reduces the net positive charge in this region of the toxin. This is likely the reason why PiTX-K beta binds K+ channels from DRG neurons with a much lower affinity than does PiTX-K alpha.

PubMed: 10707030
DOI: 10.1002/(SICI)1097-0134(20000301)38:4<441::AID-PROT9>3.3.CO;2-C

実験手法

SOLUTION NMR