Huwentoxin-V, a novel insecticidal peptide toxin from the spider Selenocosmia huwena, and a natural mutant of the toxin: indicates the key amino acid residues related to the biological activity.
A neurotoxin peptide (named Huwentoxin-V) was purified from the venom of the Chinese bird spider Selenocosmia huwena by a combination of ion exchange chromatography and reverse phase HPLC. HWTX-V has 35 amino acid residues, and is in perfect agreement with the molecular mass 4111.4 Da identified by mass spectrometry. A natural mutant of the toxin (called mHuwentoxin-V) was also isolated from the venom. mHWTX-V was only truncated two amino acid residues from the C-terminus of HWTX-V, and its molecular weight is 3877.1 Da determined by mass spectrometry. The six cysteine residues in each sequence of the two peptides suggest three disulfide bridges, the present of which was demonstrated by mass spectrometry after dithiothreiotol reduce and S-carboxymethylation. The primary structure of the two toxins exhibits sequence identity with other spider toxins such as ProTx-I (64%), SGTx (57%), SNX-482 (55%), and Hanatoxin (54%). HWTX-V can reversibly paralyze locusts and cockroaches for several hours with a ED50 value as 16 +/- 5 microg/g to locusts, and a larger dose of the toxin can cause death. However, mHWTX-V shows no significant effect on locusts and cockroaches. The structure-activity relationship indicates that the residues Phe34 and Ser35 in the C-terminus of HWTX-V are the key residues of the biological activity.
Zhang
Peng-Fei
PF
College of Life Science, Hunan Normal University, Changsha 410081, People's Republic of China.
Chen
Ping
P
Hu
Wei-Jun
WJ
Liang
Song-Ping
SP
D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003058:Cockroaches / Q000187:drug effects / Q000502:physiology; D005260:Female; D006110:Grasshoppers / Q000187:drug effects / Q000502:physiology; D008297:Male; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009498:Neurotoxins / Q000737:chemistry* / Q000494:pharmacology; D010243:Paralysis / Q000139:chemically induced; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013111:Spider Venoms / Q000737:chemistry* / Q000494:pharmacology; D013112:Spiders; D013329:Structure-Activity Relationship
D009498:Neurotoxins; D013111:Spider Venoms; C477808:huwentoxin-V, Selenocosmia huwena