Isolation of δ‐missulenatoxin‐Mb1a, the major vertebrate‐active spider δ‐toxin from the venom of Missulena bradleyi (Actinopodidae)

FEBS Letters

Chong, Youmie²  Hains, Peter G³  Khalife, Ali A²  Nicholson, Graham M²  Gunning, Simon J²  Broady, Kevin W¹ 

[1] Department of Cell and Molecular Biology, University of Technology, Sydney, NSW 2007, Australia;Department of Health Sciences, University of Technology, Sydney, NSW 2007, Australia;Department of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia

关键词: Spider;    Peptide;    δ-Missulenatoxin;    Sodium channel;    Scorpion toxin;    δ-Atracotoxin;    δ-MSTX-Mb1a;    δ-missulenatoxin-Mb1a from the eastern mouse spider Missulena bradleyi;    TTX;    tetrodotoxin;    δ-ACTX;    δ-atracotoxins from Australian funnel-web spiders;    δ-ACTX-Ar1a;    δ-atracotoxin-Ar1a (formerly robustoxin) from the Sydney funnel-web spider Atrax robustus;    δ-ACTX-Hv1a;    δ-atracotoxin-Hv1a (formerly versutoxin) from the Blue Mountains funnel-web spider Hadronyche versuta;    δ-ACTX-Hv1b;    δ-atracotoxin-Hv1b from Hadronyche versuta;    δ-ACTX-Hs20.1a;    δ-atracotoxin-Hs20.1a from Hadronyche sp. 20;    Lqh II;    anti-mammal α-toxin from the scorpion Leiurus quinquestriatus hebraeus;    Aah-II;    anti-mammal α-toxin from the scorpion Androctonus australis hector;    LqhαIT;    α-insect toxin from the scorpion Leiurus quinquestriatus hebraeus;    SDS–PAGE;    sodium dodecyl sulphate–polyacrylamide gel electrophoresis;    PVDF;    polyvinylidene fluoride;    TBS;    Tris-buffered saline;    FWS-AV;    Sydney funnel-web spider antivenom;    RP-HPLC;    reverse-phase high-performance liquid chromatography;    TFA;    trifluoroacetic acid;    DRG;    dorsal root ganglion;    HEPES;    N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid;    TEA;    tetraethylammonium;    (+)-TC;    (+)-tubocurarine;    LD50;    median lethal dose;    PD50;    median paralytic dose;    ApB;    anthopleurin-B from the sea anemone Anthopleura xanthogrammica;    Magi 4;    sodium channel toxin from the spider Macrothele gigas;   

DOI  :  10.1016/S0014-5793(03)01175-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The present study describes the isolation and pharmacological characterisation of the neurotoxin δ-missulenatoxin-Mb1a (δ-MSTX-Mb1a) from the venom of the male Australian eastern mouse spider, Missulena bradleyi. This toxin was isolated using reverse-phase high-performance liquid chromatography and was subsequently shown to cause an increase in resting tension, muscle fasciculation and a decrease in indirect twitch tension in a chick biventer cervicis nerve-muscle bioassay. Interestingly, these effects were neutralised by antivenom raised against the venom of the Sydney funnel-web spider Atrax robustus. Subsequent whole-cell patch-clamp electrophysiology on rat dorsal root ganglion neurones revealed that δ-MSTX-Mb1a caused a reduction in peak tetrodotoxin (TTX)-sensitive sodium current, a slowing of sodium current inactivation and a hyperpolarising shift in the voltage at half-maximal activation. In addition, δ-MSTX-Mb1a failed to affect TTX-resistant sodium currents. Subsequent Edman degradation revealed a 42-residue peptide with unusual N- and C-terminal cysteines and a cysteine triplet (Cys^14-16). This toxin was highly homologous to a family of δ-atracotoxins (δ-ACTX) from Australian funnel-web spiders including conservation of all eight cysteine residues. In addition to actions on sodium channel gating and kinetics to δ-ACTX, δ-MSTX-Mb1a caused significant insect toxicity at doses up to 2000 pmol/g. δ-MSTX-Mb1a therefore provides evidence of a highly conserved spider δ-toxin from a phylogenetically distinct spider family that has not undergone significant modification.

【 授权许可】

Unknown