title: Arthropod defensins illuminate the divergence of scorpion neurotoxins.
abstract: Defensins are phylogenetically ancient antibacterial polypeptides found in plants and animals. Isolation of the cDNA and genomic sequences encoding the scorpion (Leiurus quinquestriatus hebraeus) defensin revealed similarity to scorpion neurotoxins in gene organization (two exons and a phase I intron) and intron characteristics (conserved acceptor, donor and putative branch sites). This commonality, alongside a similar core structure, protein sequence and bioactivity suggest that arthropod defensins and scorpion neurotoxins share a common ancestor. Interestingly, phylogenetic analysis of defensins and scorpion neurotoxins illuminates for the first time a putative evolutionary trajectory for scorpion sodium and potassium channel neurotoxins.
authors.affiliation: Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food, and Environmental Quality, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel. froy@agri.huji.ac.il
authors.forename: Oren
authors.initials: O
authors.lastname: Froy
authors.forename: Michael
authors.initials: M
authors.lastname: Gurevitz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001181:Arthropods / Q000235:genetics; D001483:Base Sequence; D023082:Defensins / Q000235:genetics*; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D012605:Scorpions / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D023082:Defensins; D009498:Neurotoxins