Hainantoxin-II （HnTx-II）, a novel neurotoxin, was isolated from the venom of the Chinese bird spider （Haplopelma hainanum） by cation exchange chromatography and reverse-phase HPLC. The toxin was a single chain pol...Hainantoxin-II （HnTx-II）, a novel neurotoxin, was isolated from the venom of the Chinese bird spider （Haplopelma hainanum） by cation exchange chromatography and reverse-phase HPLC. The toxin was a single chain polypeptide with calculated molecular weight of 4 253.135 obtained by mass spectrometry. The complete amino acid sequence of HnTx-II was determined by Edman degradation and found to contain 37 residues with three disulfide bonds. Results showed HnTx-II can reversibly paralyze cockroaches for several hours after intra-abdominal injection with ED50 of 16 μg/g and kill the insects immediately at a dose of 60 μg/g. It was also shown to kill mice at a LD50 value of 1.41μg/g after intracerebroventricular injection. Hainantoxin-II shares 91% sequence homology with Huwentoxin-II （HwTx-II）, an insecticidal peptide from another bird spider （Haplopelma schmidti） with a unique scaffold. While HnTx-II and HwTx-II both exhibit toxic activities in insects and mammals, HnTx-II shows higher insecticidal activity and lower lethiferous activity of mammals than HwTx-II. These results help clarify structural-functional relationships of the polypeptide toxin.展开更多
Tarantula venoms provide a model system for studying toxin selectivity, structure-activity relationships and molecular evolution ofpeptide toxins. Previous studies have identified a large number of peptide toxins in t...Tarantula venoms provide a model system for studying toxin selectivity, structure-activity relationships and molecular evolution ofpeptide toxins. Previous studies have identified a large number of peptide toxins in the venom of the Chinese bird spider Haplopelma hainanum, generally regarded as a highly venomous spider. However, the lack of available RNA-seq transcriptomic and genomic data is an obstacle to understanding its venom at the molecular level. In this study, we investigated the venom gland transcriptome of/-/, hainanum by RNA-seq, in the absence of an available genomic sequence. We identi- fied 201 potential toxins among 57 18 l de novo assembled transcripts, including knottins, Kunitz-type toxins, enzymes and other proteins. We systematically identified most of the knottins and Kunitz-type toxins, some of which showed strongly biased expression in the venom gland, including members of the huwentoxin-1, huwentoxin-2 and magi-1 families. We also discovered several novel potential toxins. These data demonstrate the high molec- ular and structural diversity in the venom toxins ofH. hainanum. This study offers a useful strategy for exploring the complex components of spider venoms.展开更多
基金supported by the Research Project of the Education Department of Zhejiang Province, China (Y200805989)~~
文摘Hainantoxin-II （HnTx-II）, a novel neurotoxin, was isolated from the venom of the Chinese bird spider （Haplopelma hainanum） by cation exchange chromatography and reverse-phase HPLC. The toxin was a single chain polypeptide with calculated molecular weight of 4 253.135 obtained by mass spectrometry. The complete amino acid sequence of HnTx-II was determined by Edman degradation and found to contain 37 residues with three disulfide bonds. Results showed HnTx-II can reversibly paralyze cockroaches for several hours after intra-abdominal injection with ED50 of 16 μg/g and kill the insects immediately at a dose of 60 μg/g. It was also shown to kill mice at a LD50 value of 1.41μg/g after intracerebroventricular injection. Hainantoxin-II shares 91% sequence homology with Huwentoxin-II （HwTx-II）, an insecticidal peptide from another bird spider （Haplopelma schmidti） with a unique scaffold. While HnTx-II and HwTx-II both exhibit toxic activities in insects and mammals, HnTx-II shows higher insecticidal activity and lower lethiferous activity of mammals than HwTx-II. These results help clarify structural-functional relationships of the polypeptide toxin.
文摘Tarantula venoms provide a model system for studying toxin selectivity, structure-activity relationships and molecular evolution ofpeptide toxins. Previous studies have identified a large number of peptide toxins in the venom of the Chinese bird spider Haplopelma hainanum, generally regarded as a highly venomous spider. However, the lack of available RNA-seq transcriptomic and genomic data is an obstacle to understanding its venom at the molecular level. In this study, we investigated the venom gland transcriptome of/-/, hainanum by RNA-seq, in the absence of an available genomic sequence. We identi- fied 201 potential toxins among 57 18 l de novo assembled transcripts, including knottins, Kunitz-type toxins, enzymes and other proteins. We systematically identified most of the knottins and Kunitz-type toxins, some of which showed strongly biased expression in the venom gland, including members of the huwentoxin-1, huwentoxin-2 and magi-1 families. We also discovered several novel potential toxins. These data demonstrate the high molec- ular and structural diversity in the venom toxins ofH. hainanum. This study offers a useful strategy for exploring the complex components of spider venoms.
