title: Purification and characterization of a short insect toxin from the venom of the scorpion Buthus tamulus.
abstract: A short chain peptide has been isolated from the venom of a red scorpion of Indian origin, Buthus tamulus. This peptide was purified using ion exchange and reverse phase chromatography and was characterized by molecular weight determination and amino acid sequence. The primary structure analysis shows that BtITx3 is a short peptide of 35 amino acid residues having a molecular weight of 3796 Da. The toxin shows toxicity towards the Lepidopteran species of insect Helicoverpa armigera causing flaccid paralysis and even death within 24 h. It shows more than 50% homology with the short insectotoxins having four disulfide bridges, which suggests that the toxin belongs to the class of short chain toxins blocking the chloride ion channels. This sequence homology study has also helped to bring out the structure-function relationship between the various short toxins. Homology modeling done by using template structure of a known toxin indicated that this toxin consists of a similar alpha/beta scaffold, as present in other scorpion toxins.
authors.affiliation: Biomembrane Lab, Department of Chemistry and School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.
authors.forename: Ritu Dhawan
authors.initials: RD
authors.lastname: Dhawan
authors.forename: Suresh
authors.initials: S
authors.lastname: Joseph
authors.forename: Anurag
authors.initials: A
authors.lastname: Sethi
authors.forename: Anil K
authors.initials: AK
authors.lastname: Lala
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D007915:Lepidoptera; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D012604:Scorpion Venoms / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000633:toxicity; D012605:Scorpions / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: C109066:KTX toxin, Buthus; D012604:Scorpion Venoms