New "Birtoxin analogs" from Androctonus australis venom.
From the venom of the scorpion Androctonus australis, we have isolated a new bioactive polypeptide termed AaBTX-L1. When tested on the insect voltage-gated Na(+) channel (para) of the fruit fly, this toxin was able to induce a clear shift in activation (V(1/2)), resulting in the opening of the channel at more negative membrane potentials. Furthermore, AaBTX-L1 was totally devoid of toxicity when injected into mice intracerebroventricularly and did not compete with radiolabeled voltage-gated K(+) and Na(+) channel toxins in binding experiments on rat brain synaptosomes. Using its N-terminal amino acid sequence to design degenerate primers, several clones were amplified by PCR from the A. australis venom gland cDNA library. As a consequence, seven full oligonucleotide sequences encoding "long-chain" polypeptides with only three disulfide bridges have been cloned for the first time and are described here. Remarkably, they share high similarity with the anti-insect toxin Birtoxin from Parabuthus transvaalicus.
Martin-Eauclaire
Marie-France
MF
CNRS FRE 2738, Ingénierie des Protéines, Faculté de Médecine secteur Nord, Institut Jean Roche, Université de la Méditerranée, Bd Pierre Dramard, 13916 Marseille 20, France. eauclaire.mf@jean-roche.univ-mrs.fr
Ceard
Brigitte
B
Bosmans
Frank
F
Rosso
Jean-Pierre
JP
Tytgat
Jan
J
Bougis
Pierre E
PE
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D012604:Scorpion Venoms / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity*; D012605:Scorpions / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D016019:Survival Analysis; D013574:Synaptosomes / Q000378:metabolism*; D014982:Xenopus laevis
D012604:Scorpion Venoms; C440191:birtoxin