Purification and characterization of raventoxin-I and raventoxin-III, two neurotoxic peptides from the venom of the spider Macrothele raveni.
The spider Macrothele raveni was recently identified as a new species of Genus Macrothele. The crude venom from M. raveni was found to be neurotoxic to mice and the LD(50) of the crude venom in mice was 2.852mg/kg. Two neurotoxic peptides, raventoxin-I and raventoxin-III, were isolated from the crude venom by ion-exchange and reverse phase high performance liquid chromatography. Raventoxin-I was the most abundant toxic component in the venom, while raventoxin-III was a lower abundant component. Both toxins can kill mice and block neuromuscular transmission in an isolated mouse phrenic nerve diaphragm preparation, but have no effect on cockroaches. The LD(50) of raventoxin-I in mice is 0.772mg/kg. The complete amino acid sequences of raventoxin-I and raventoxin-III were determined and found to consist of 43 and 29 amino acid residues, respectively. It was determined by mass spectrometry that all Cys residues from raventoxin-I and raventoxin-III are involved in disulphide bonds. raventoxin-III showed no significant sequence homology with any presently known neurotoxins in the protein/DNA databases, while raventoxin-I has limited sequence identity with delta-AcTx-Hv1 and delta-AcTx-Ar1, which target both mammalian and insect sodium channels. Both raventoxin-I and raventoxin-III only work on vertebrates, but not on insects. Moreover, raventoxin-I could exert an effect of first exciting and then inhibiting the contraction of mouse diaphragm muscle caused by electrically stimulating the phrenic nerve, but raventoxin-III could not.
Zeng
Xiong-Zhi
XZ
Department of Biology, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.
Xiao
Qiao-Bin
QB
Liang
Song-Ping
SP
D000595:Amino Acid Sequence; D000818:Animals; D004305:Dose-Response Relationship, Drug; D007928:Lethal Dose 50; D051379:Mice; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D010791:Phrenic Nerve / Q000187:drug effects / Q000502:physiology; D013111:Spider Venoms / Q000737:chemistry*; D013112:Spiders
D009498:Neurotoxins; D010455:Peptides; D013111:Spider Venoms