title: Purification, structure determination and synthesis of covalitoxin-II, a short insect-specific neurotoxic peptide from the venom of the Coremiocnemis validus (Singapore tarantula).
abstract: Spider venoms contain toxins that specifically immobilize and kill insects. We report the purification and characterization of a new insect-specific toxin named covalitoxin-II (Cvtx-II; mass, 3406. 24+/-0.64), from Coremiocnemis validus (Singapore tarantula) venom. The complete 31 amino acid sequence of Cvtx-II has been determined and it shows less than 40% identity with spider toxins. However, Cvtx-II has conserved cystine motif analogous to other spider and omega-conotoxins. Cvtx-II was chemically synthesized and identified with the native Cvtx-II. Synthetic Cvtx-II induced insect-specific non-lethal excitatory activity when injected into crickets, but not in cockroaches and mice.
authors.affiliation: Venom and Toxin Research Programme, Department of Anatomy, Faculty of Medicine, National University of Singapore, Singapore.
authors.forename: R A
authors.initials: RA
authors.lastname: Balaji
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: P
authors.initials: P
authors.lastname: Gopalakrishnakone
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: R M
authors.initials: RM
authors.lastname: Kini
authors.forename: B H
authors.initials: BH
authors.lastname: Bay
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003058:Cockroaches / Q000187:drug effects / Q000502:physiology; D003553:Cystine / Q000378:metabolism; D006135:Gryllidae / Q000187:drug effects / Q000502:physiology; D008124:Locomotion / Q000187:drug effects; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009043:Motor Activity / Q000187:drug effects; D009498:Neurotoxins / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification* / Q000633:toxicity; D010243:Paralysis / Q000139:chemically induced; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D013045:Species Specificity; D013111:Spider Venoms / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification* / Q000633:toxicity
chemical_list: D009498:Neurotoxins; D013111:Spider Venoms; C410350:covalitoxin II; D003553:Cystine