title: Novel lynx spider toxin shares common molecular architecture with defense peptides from frog skin.
abstract: A unique 30-residue cationic peptide oxyopinin 4a (Oxt 4a) was identified in the venom of the lynx spider Oxyopes takobius (Oxyopidae). Oxt 4a contains a single N-terminally located disulfide bond, Cys4-Cys10, and is structurally different from any spider toxin studied so far. According to NMR findings, the peptide is disordered in water, but assumes a peculiar torpedo-like structure in detergent micelles. It features a C-terminal amphipathic α-helical segment (body; residues 12-25) and an N-terminal disulfide-stabilized loop (head; residues 1-11), and has an unusually high density of positive charge in the head region. Synthetic Oxt 4a was produced and shown to possess strong and broad-spectrum cytolytic and antimicrobial activity. cDNA cloning showed that the peptide is synthesized in the form of a conventional prepropeptide with an acidic prosequence. Unlike other arachnid toxins, Oxt 4a exhibits striking similarity with defense peptides from the skin of ranid frogs that contain the so-called Rana-box motif (a C-terminal disulfide-enclosed loop). Parallelism or convergence is apparent on several levels: the structure, function and biosynthesis of a lynx spider toxin are mirrored by those of Rana-box peptides from frogs.
authors.affiliation: M M Shemyakin and Yu A Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia. peter@nmr.ru
authors.forename: Peter V
authors.initials: PV
authors.lastname: Dubovskii
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Vassilevski
authors.forename: Olga V
authors.initials: OV
authors.lastname: Samsonova
authors.forename: Natalya S
authors.initials: NS
authors.lastname: Egorova
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Kozlov
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Feofanov
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Arseniev
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Grishin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D002942:Circular Dichroism; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D006461:Hemolysis / Q000187:drug effects; D007306:Insecticides / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011898:Ranidae; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000378:metabolism*; D013111:Spider Venoms / Q000737:chemistry* / Q000494:pharmacology*; D013112:Spiders
chemical_list: D023181:Antimicrobial Cationic Peptides; D007306:Insecticides; D013111:Spider Venoms