title: Sequence-specific 1H-NMR assignment and determination of the secondary structure of hainantoxin-III from the spider Ornithoctonus hainana.
abstract: Hainantoxin-III (HNTX-III) purified from the venom of the spider Ornithoctonus hainana is a novel neurotoxin preferentially inhibiting tetrodotoxin-sensitive voltage-gated sodium channels in rat dorsal root ganglion cells. The structure of this toxin in aqueous solution was investigated using 2-D 1H-NMR techniques. The complete sequencespecific assignments of proton resonances in the 1H-NMR spectra were obtained by analyzing a series of 2-D spectra, including DQF-COSY, TOCSY and NOESY spectra, in H2O or D2O. All the backbone protons and more than 95% of the side-chain protons have been assigned by dαN, dβN, and dNN connectivities in NOESY spectrum. Furthermore, the secondary structure of HNTX-III was identified from NMR data. It consists mainly of a short triple-stranded antiparallel β-sheet formed by Asp7 to Cys9, Tyr21 to Ser23, and Lys27 to Val30. Because HNTX-III shares high sequence identity (>70%) with HWTX-I and HNTX-I, we proposed that they all share a structural scaffold known as the inhibitor cystine knot architectural motif. This study provides a basis for the further determination of the solution conformation of HNTX-III.
authors.affiliation: College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, P. R. China.
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Liu
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhu
authors.forename: Weijun
authors.initials: W
authors.lastname: Hu
authors.forename: Songping
authors.initials: S
authors.lastname: Liang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D041961:Deuterium Exchange Measurement; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D013111:Spider Venoms / Q000737:chemistry*; D013112:Spiders / Q000737:chemistry*
chemical_list: D013111:Spider Venoms