title: Proton nuclear magnetic resonance studies on huwentoxin-I from the venom of the spider Selenocosmia huwena: 2. Three-dimensional structure in solution.
abstract: The three-dimensional structure in aqueous solution of native huwentoxin-I, a neurotoxin from the venom of the spider Selenocosmia huwena, has been determined from two-dimensional H NMR data recorded at 500 and 600 MHz. Structural constraints consisting of interproton distances inferred from NOEs and dihedral angles from spin-spin coupling constants were used as input for distance geometry calculation with the program XPLOR 3.1. The best 10 structures have NOE violations < 0.3 A, dihedral violations < 2 degrees, and pairwise root-mean-square differences of 1.08 (+/- 0.20) A over backbone atoms (N, C alpha, C). The molecule adopts a compact structure consisting of a small triple-stranded antiparallel beta-sheet and five beta-turns. A small hydrophobic patch consisting of Phe 6, Trp 28, and Trp 31 is located on one side of the molecule. All six lysine residues are distributed on the molecular surface. The three disulfide bridges are buried within the molecule. The structure contains an "inhibitor cystine knot motif" which is adopted by several other small proteins, such as omega-conotoxin, agatoxin IVA, and gurmarin.
authors.affiliation: Department of Biology, Peking University, Beijing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Qu
authors.forename: S
authors.initials: S
authors.lastname: Liang
authors.forename: J
authors.initials: J
authors.lastname: Ding
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Zhang
authors.forename: X
authors.initials: X
authors.lastname: Gu
mesh_terms: D000595:Amino Acid Sequence; D001667:Binding, Competitive; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000737:chemistry* / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011522:Protons; D011978:Receptors, Nicotinic / Q000378:metabolism; D030162:Reptilian Proteins; D012996:Solutions; D013111:Spider Venoms / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship; D020866:omega-Conotoxin GVIA
chemical_list: D009498:Neurotoxins; D010455:Peptides; D011522:Protons; D011978:Receptors, Nicotinic; D030162:Reptilian Proteins; D012996:Solutions; D013111:Spider Venoms; C083624:huwentoxin I; D020866:omega-Conotoxin GVIA