title: Molecular cloning, bioinformatics analysis and functional characterization of HWTX-XI toxin superfamily from the spider Ornithoctonus huwena.
abstract: Spider venom contains a very valuable repertoire of natural resources to discover novel components for molecular diversity analyses and therapeutic applications. In this study, HWTX-XI toxins from the spider venom glands of Ornithoctonus huwena which are Kunitz-type toxins (KTTs) and were directly cloned, analyzed and functionally characterized. To date, the HWTX-XI superfamily consists of 38 members deduced from 121 high-quality expressed sequence tags, which is the largest spider KTT superfamily with significant molecular diversity mainly resulted from cDNA tandem repeats as well as focal hypermutation. Among them, HW11c40 and HW11c50 may be intermediate variants between native Kunitz toxins and sub-Kunitz toxins based on evolutionary analyses. In order to elucidate their biological activities, recombinant HW11c4, HW11c24, HW11c27 and HW11c39 were successfully expressed, further purified and functionally characterized. Both HW11c4 and HW11c27 display inhibitory activities against trypsin, chymotrypsin and kallikrein. Moreover, HW11c4 is also an inhibitor relatively specific for Kv1.1 channels. HW11c24 and HW11c39 are found to be inactive on chymotrysin, trypsin, kallikrein, thrombin and ion channels. These findings provide molecular evidence for toxin diversification of the HWTX-XI superfamily and useful molecular templates of serine protease inhibitors and ion channel blockers for the development of potentially clinical applications.
authors.affiliation: Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China. Electronic address: jiangliping@csu.edu.cn.
authors.forename: Liping
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Department of Biochemistry, School of Life Sciences, Central South University, Changsha, Hunan 410013, PR China.
authors.forename: Meichun
authors.initials: M
authors.lastname: Deng
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, PR China.
authors.forename: Zhigui
authors.initials: Z
authors.lastname: Duan
authors.affiliation: College of Chemistry, Biology, and Material Science, East China Institute of Technology, Nanchang, Jiangxi 330013, PR China.
authors.forename: Xing
authors.initials: X
authors.lastname: Tang
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, PR China. Electronic address: liangsp@hunnu.edu.cn.
authors.forename: Songping
authors.initials: S
authors.lastname: Liang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D005260:Female; D051662:Kv1.1 Potassium Channel / Q000037:antagonists & inhibitors; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects; D010802:Phylogeny; D020033:Protein Isoforms; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D015842:Serine Proteinase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D013111:Spider Venoms / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D013112:Spiders / Q000737:chemistry* / Q000235:genetics; D014982:Xenopus laevis
chemical_list: D020033:Protein Isoforms; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; D013111:Spider Venoms; C510374:hwentoxin-X, Ornithoctonus huwena; D051662:Kv1.1 Potassium Channel
keywords: Evolution; K(+) channel blocker; Kunitz-type toxin; Ornithoctonus huwena; Spider toxin; Trypsin inhibitor