title: Sequence-specific assignment of 1H-NMR resonance and determination of the secondary structure of Jingzhaotoxin-I.
abstract: Jingzhaotoxin-I (JZTX-I) purified from the venom of the spider Chilobrachys jingzhao is a novel neurotoxin preferentially inhibiting cardiac sodium channel inactivation by binding to receptor site 3. The structure of this toxin in aqueous solution was investigated using 2-D 1H-NMR techniques. The complete sequence-specific assignments of proton resonance in the 1H-NMR spectra of JZTX-I were obtained by analyzing a series of 2-D spectra, including DQF-COSY, TOCSY and NOESY spectra, in H2O and D2O. All the backbone protons except for Gln4 and more than 95% of the side-chain protons were identified by d alphaN, d alphadelta, d betaN and d NN connectivities in the NOESY spectrum. These studies provide a basis for the further determination of the solution conformation of JZTX-I. Furthermore, the secondary structure of JZTX-I was identified from NMR data. It consists mainly of a short triple-stranded antiparallel beta-sheet with Trp7-Cys9, Phe20-Lys23 and Leu28-Trp31. The characteristics of the secondary structure of JZTX-I are similar to those of huwentoxin-I (HWTX-I) and hainantoxin-IV (HNTX-IV), whose structures in solution have previously been reported.
authors.affiliation: College of Life Sciences, Hunan Normal University, Changsha 410081, China.
authors.forename: Xiong-Zhi
authors.initials: XZ
authors.lastname: Zeng
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhu
authors.forename: Song-Ping
authors.initials: SP
authors.lastname: Liang
mesh_terms: D000595:Amino Acid Sequence; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008969:Molecular Sequence Data; D010449:Peptide Mapping / Q000379:methods*; D010455:Peptides / Q000032:analysis* / Q000737:chemistry*; D017433:Protein Structure, Secondary; D011522:Protons; D020539:Sequence Analysis, Protein / Q000379:methods*; D013111:Spider Venoms / Q000032:analysis* / Q000737:chemistry*
chemical_list: D010455:Peptides; D011522:Protons; D013111:Spider Venoms; C500354:jingzhaotoxin-I, Chilobrachys jingzhao