title: Toxin III of the scorpion Androctonus australis Hector: proton nuclear magnetic resonance assignments and secondary structure.
abstract: 1H NMR has been applied to a 3.5 mM, pH 5.4, solution of toxin III (64 amino acids) from venom of the scorpion Androctonus australis Hector. The resonance assignment strategy began by applying a generalized main-chain directed method for rapid identification and resonance assignments of secondary structures. The remaining resonances were assigned by the sequential method. Major structural features include a helix of 2 1/2 turns (residues 20-28) which is linked by two disulfide bridges to the central strand of a triple-stranded anti-parallel beta-sheet. Turns were identified at residues 15-17, 47-49 and also at residues 51-53. Numerous NOEs have been observed between hydrophobic residues which suggest the presence of a hydrophobic core; these include Leu37, Leu23, Val47, Tyr14, Trp45 and Tyr5. The Trp45 and Tyr5 rings lie orthogonal to one another. No crystal structure has been solved for this AaH III toxin. Comparisons are made with other members of the scorpion toxin family.
authors.affiliation: Laboratoire de R.M.N. ICSN CNRS, Gif-sur-Yvette, France.
authors.forename: A
authors.initials: A
authors.lastname: Mikou
authors.forename: S R
authors.initials: SR
authors.lastname: LaPlante
authors.forename: E
authors.initials: E
authors.lastname: Guittet
authors.forename: J Y
authors.initials: JY
authors.lastname: Lallemand
authors.forename: M F
authors.initials: MF
authors.lastname: Martin-Eau Claire
authors.forename: H
authors.initials: H
authors.lastname: Rochat
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009479:Neuropeptides / Q000737:chemistry* / Q000302:isolation & purification; D011487:Protein Conformation; D012604:Scorpion Venoms / Q000737:chemistry*; D012605:Scorpions
chemical_list: D009479:Neuropeptides; D012604:Scorpion Venoms; C067223:scorpion toxin AaH III