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 ...
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.
Related Citations:
Proton Nuclear Magnetic Resonance Studies on Huwentoxin-I from the Venom of the Spider Selenocosmia Huwena:1.Sequence-Specific 1H-NMR Assignment Qu, Y., Liang, S., Ding, J., Ma, L., Zhang, R., Gu, X. (1995) J Protein Chem 14: 549
Properties and Amino Acid Sequence of Huwentoxin-I, a Neurotoxin Purified from the Venom of the Chinese Bird Spider Selenocosmia Huwena Liang, S., Zhang, D., Pan, X., Chen, Q., Zhou, P. (1993) Toxicon 31: 969
Assignment of the Three Disulfide Bridges of Huwentoxin-I,A Neurotoxin from the Spider Selenocosmia Huwena Zhang, D., Liang, S. (1993) J Protein Chem 12: 735
Organizational Affiliation:
Department of Biology, Peking University, Beijing, China.
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