1LQQ

ANTI-MAMMAL AND ANTI-INSECT LQQIII SCORPION TOXIN, NMR, 15 STRUCTURES

1LQQ の概要

• エントリーDOI: 10.2210/pdb1lqq/pdb
• 分子名称: LQQIII (1 entity in total)
• 機能のキーワード: neurotoxin, lqqiii, scorpion toxin, csalpha-beta motif, sodium channel inhibitor
• 由来する生物種: Leiurus quinquestriatus quinquestriatus (Egyptian scorpion)
• 細胞内の位置: Secreted: P01487
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 7248.19

構造登録者

Landon, C.,Sodano, P.,Vovelle, F.,Ptak, M. (登録日: 1997-05-18, 公開日: 1998-05-20, 最終更新日: 2024-10-16)

主引用文献

Landon, C.,Cornet, B.,Bonmatin, J.M.,Kopeyan, C.,Rochat, H.,Vovelle, F.,Ptak, M.
1H-NMR-derived secondary structure and the overall fold of the potent anti-mammal and anti-insect toxin III from the scorpion Leiurus quinquestriatus quinquestriatus.
Eur.J.Biochem., 236:395-404, 1996

PubMed Abstract: We describe the secondary structure and the overall fold of toxin III from the venom of the scorpion Leiurus quinquestriatus quinquestriatus determined using two-dimensional-1H-NMR spectroscopy. This protein, which contains 64 amino acids and 4 disulfide bridges, belongs to the long-chain toxin category and is highly toxic to both mammals and insects. The overall fold was determined on the basis of 1208 inter-proton-distance restraints derived from NOE measurements and 90 psi, phi dihedral-angle restraints derived from NOE connectivities and 3JNH-alphaH coupling constants using the HABAS program. This fold, which mainly consists of an alpha-helix packed against a small antiparallel three-stranded beta-sheet, and of several turns and loops, is similar to that of other long-chain scorpion toxins. Aromatic and non-polar residues form several patches on the surface of the protein which alternate with patches of charged and polar residues. Such a topology should be important in the interactions of toxin III with sodium channels in membranes. Two weakly constrained loops introduce some flexibility to the structure which could be related to the activity of this toxin. The central core of toxin III is compared with the cysteine-stabilized alpha beta motif (an alpha-helix connected to a beta-sheet through two disulfide bridges) found in insect defensins and plant thionins. Defensins and thionins are small proteins (approximately 40--50 amino acid residues) containing three or four disulfide bridges, respectively. This comparison confirms that the cysteine-stabilized alpha beta motif is a common core to a number of small proteins from different origins and having different activities.

PubMed: 8612608
DOI: 10.1111/j.1432-1033.1996.00395.x

実験手法

SOLUTION NMR