title: Nuclear magnetic resonance studies on huwentoxin-XI from the Chinese bird spider Ornithoctonus huwena: 15N labeling and sequence-specific 1H, 15N nuclear magnetic resonance assignments.
abstract: Huwentoxin-XI purified from the Chinese bird spider Ornithoctonus huwena is a toxin with both antiprotease activity and potassium channel blocking activity. To determine its solution structure, huwentoxin-XI was expressed in a yeast eukaryotic expression system and studied by NMR. The 15N labeling strategy was used to facilitate the process of resonance assignments. The nearly complete sequence-specific assignments of proton and nitrogen resonances were obtained by analyzing a series of two-dimensional (2D) and three-dimensional (3D) spectra, including DQF-COSY, TOCSY, NOESY, 15N-1H HSQC, 15N-1H HNHA, 15N-1H HNHB, 15N-1H TOCSY-HSQC and 15N-1H NOESY-HSQC spectra. Secondary structure analysis of huwentoxin-XI showed that it mainly contains an N-terminal 310-helix from Thr3 to Arg5 and a C-terminal alpha-helix from Gln45 to Cys52, plus a triple-stranded antiparallel beta-sheet of Glu18-Asn23, Thr26-Ile31 and Asn40-Lys41. These studies provide a solid basis for the final structure determination of huwentoxin-XI.
authors.affiliation: College of Life Science, Peking University, Beijing 100871, China. liangsp@hunnu.edu.cn.
authors.forename: Kuan
authors.initials: K
authors.lastname: Peng
authors.forename: Ying
authors.initials: Y
authors.lastname: Lin
authors.forename: Song-Ping
authors.initials: SP
authors.lastname: Liang
mesh_terms: D000818:Animals; D006860:Hydrogen Bonding; D019906:Nuclear Magnetic Resonance, Biomolecular; D026902:Potassium Channel Blockers / Q000737:chemistry; D011480:Protease Inhibitors / Q000737:chemistry; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D013111:Spider Venoms / Q000737:chemistry*; D013112:Spiders / Q000737:chemistry
chemical_list: D026902:Potassium Channel Blockers; D011480:Protease Inhibitors; D011994:Recombinant Proteins; D013111:Spider Venoms