An Buthus martensii Karsch Insect Toxin (BmK IT ) gene was inserted into the genome of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) to construct a recombinant baculovirus, AcMNPV-BmK IT. The expres...An Buthus martensii Karsch Insect Toxin (BmK IT ) gene was inserted into the genome of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) to construct a recombinant baculovirus, AcMNPV-BmK IT. The expression of BmK IT was confirmed using RT-PCR, dot blot and SDS-PAGE analysis. Dose-lethal time responses to Spodoptera exigua larvae were compared between wild-type baculovirus AcMNPV and recombinant virus AcMNPV-BmK IT. At the concentration of 1×107 PIBs/mL, the median lethal time of recombinant baculovirus (LT50 = 73.6h) on third instar S. exigua larvae showed an improvement of 13.2% over the efficacy of wild type virus (LT50 = 84.8h) during a 192h in-fection.展开更多
A natural scorpion toxin BmK 16 was purified for the first time from the venom of the Chinese scorpion Buthus martensii Karsch (BmK) by using combined gel filtration, ion exchange and reversed phase chromatograph...A natural scorpion toxin BmK 16 was purified for the first time from the venom of the Chinese scorpion Buthus martensii Karsch (BmK) by using combined gel filtration, ion exchange and reversed phase chromatography. The sequence of the N terminal 8 amino acid residues was determined by Edman degradation. Using the N terminal sequence as a tag, the database searching revealed a hit in the scorpion cDNA Bank. The sequence for N terminal 8 amino acid residues, molecular weight and amino acid compositions of BmK 16 were identical with the calculated values according to the first 64 residues' sequence of the precursor peptide alpha neurotoxin TX16 derived from the sequence of the cDNA AF156597 (EMBL). The sequence specific resonance assignment of BmK 16 was achieved and the intact sequence of BmK 16 was determined as followings: VRDAY IAKPH NCVYE CARNE YCNDL CTKNG AKSGY CQWVG KYGNG CWCKE LPDNV PIRVP GKCH. Furthermore, the results from the sequence homology analysis and the toxicity assays indicated that BmK 16 was an α like scorpion neurotoxin.展开更多
Scorpion toxins are a family of small neurotoxic proteins with high selectivity. Gener-ally, most of the toxins are a group of basic homologous polypeptides containing about60—80 amino acids except BmK Ⅳ whose pl is...Scorpion toxins are a family of small neurotoxic proteins with high selectivity. Gener-ally, most of the toxins are a group of basic homologous polypeptides containing about60—80 amino acids except BmK Ⅳ whose pl is 5.3. It has been reported that theybind to various ion channels with high affinity and selectivity. In spite of the significantsequence similarity found among different toxins, they display various degrees of toxicityand specificity to different animal species. So far they form a good system to study thestructure-function relationship.展开更多
The crystal structure of an acidic neurotoxin, BmK M8, from Chinese scorpion Buthus martensii Karsch was determined at 0.25 nm resolution. The X-ray diffraction data of BmK M8 crystals at 0.25nm resolution were collec...The crystal structure of an acidic neurotoxin, BmK M8, from Chinese scorpion Buthus martensii Karsch was determined at 0.25 nm resolution. The X-ray diffraction data of BmK M8 crystals at 0.25nm resolution were collected on a Siemens area detector. Using molecular replacement method with a basic scorpion toxin AaH II in a search model, the cross-rotation function, PC-refinement and translation function were calculated by X-PLOR program package. The correct orientation and position of BmK M8 molecule in crystal were determined in a resolution range of 1.5 - 0.35nm, The oystallographic refinement was further performed by stereo-chemical restrict least-square technique, followed by simulated annealing, slow-cooling protocols. The final crystallographic R-factor at 0.8-0.25 nm is 0.171. The standard deviations of bond length and bond angle from ideality are 0.001 7nm and 2.24° , respectively. The final model of BmK M8 structure is composed of a dense core of secondary structure elements by a stretch of α-helix with two and a half turns (residues 19-28) and a three-stranded antiparallel β-sheet (residues 2-4, 32 - 37, 45- 51). In addition, three loops protruded from the structural core. The general folding properties of BmK M8 molecule were described; a common structure motif which may appear in all scorpion neurotoxins was identified. The conserved aromatic residues and charged residues were found to be distributed on two roughly opposite surfaces of the molecule. The relationship between these two faces and receptor-binding sites are also discussed.展开更多
Scorpion anti-insect toxins can be divided into long chain (about 61-70 aminoacid residues)and short chain (about 5 amino acid residues) types according to theirmolecular size, and the former can be further divided in...Scorpion anti-insect toxins can be divided into long chain (about 61-70 aminoacid residues)and short chain (about 5 amino acid residues) types according to theirmolecular size, and the former can be further divided into excitatory and depressanttypes on the basis of their pharmacological action. In our previous papers, the iso-lation and determination of the primary structure of an excitatory展开更多
Scorpion venoms contain several kinds of neurotoxins, such as antimammalian neurotoxins, anti-insect neurotoxins and others. But most of them form a family of structurally related single chain proteins of 60—70 amino...Scorpion venoms contain several kinds of neurotoxins, such as antimammalian neurotoxins, anti-insect neurotoxins and others. But most of them form a family of structurally related single chain proteins of 60—70 amino acid residues and selectively interact with voltage-dependent sodium channels in different excitable cells, only a few minipeptides of 31—39 amino acid residues are proved to block potassium channels. As a kind of molecular probe, scorpion neurotoxins have been widely used for analyzing the展开更多
基金the National Natural Science Foundation of China (Grant Nos.30670282 and 30700534)the Department of Science and Technology of Shanxi Province
文摘An Buthus martensii Karsch Insect Toxin (BmK IT ) gene was inserted into the genome of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) to construct a recombinant baculovirus, AcMNPV-BmK IT. The expression of BmK IT was confirmed using RT-PCR, dot blot and SDS-PAGE analysis. Dose-lethal time responses to Spodoptera exigua larvae were compared between wild-type baculovirus AcMNPV and recombinant virus AcMNPV-BmK IT. At the concentration of 1×107 PIBs/mL, the median lethal time of recombinant baculovirus (LT50 = 73.6h) on third instar S. exigua larvae showed an improvement of 13.2% over the efficacy of wild type virus (LT50 = 84.8h) during a 192h in-fection.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .2 0 13 2 0 3 0 )
文摘A natural scorpion toxin BmK 16 was purified for the first time from the venom of the Chinese scorpion Buthus martensii Karsch (BmK) by using combined gel filtration, ion exchange and reversed phase chromatography. The sequence of the N terminal 8 amino acid residues was determined by Edman degradation. Using the N terminal sequence as a tag, the database searching revealed a hit in the scorpion cDNA Bank. The sequence for N terminal 8 amino acid residues, molecular weight and amino acid compositions of BmK 16 were identical with the calculated values according to the first 64 residues' sequence of the precursor peptide alpha neurotoxin TX16 derived from the sequence of the cDNA AF156597 (EMBL). The sequence specific resonance assignment of BmK 16 was achieved and the intact sequence of BmK 16 was determined as followings: VRDAY IAKPH NCVYE CARNE YCNDL CTKNG AKSGY CQWVG KYGNG CWCKE LPDNV PIRVP GKCH. Furthermore, the results from the sequence homology analysis and the toxicity assays indicated that BmK 16 was an α like scorpion neurotoxin.
基金Project supported by the National Natural Science Foundation of China.
文摘Scorpion toxins are a family of small neurotoxic proteins with high selectivity. Gener-ally, most of the toxins are a group of basic homologous polypeptides containing about60—80 amino acids except BmK Ⅳ whose pl is 5.3. It has been reported that theybind to various ion channels with high affinity and selectivity. In spite of the significantsequence similarity found among different toxins, they display various degrees of toxicityand specificity to different animal species. So far they form a good system to study thestructure-function relationship.
基金Project supported by the National Natural Science Foundation of China.
文摘The crystal structure of an acidic neurotoxin, BmK M8, from Chinese scorpion Buthus martensii Karsch was determined at 0.25 nm resolution. The X-ray diffraction data of BmK M8 crystals at 0.25nm resolution were collected on a Siemens area detector. Using molecular replacement method with a basic scorpion toxin AaH II in a search model, the cross-rotation function, PC-refinement and translation function were calculated by X-PLOR program package. The correct orientation and position of BmK M8 molecule in crystal were determined in a resolution range of 1.5 - 0.35nm, The oystallographic refinement was further performed by stereo-chemical restrict least-square technique, followed by simulated annealing, slow-cooling protocols. The final crystallographic R-factor at 0.8-0.25 nm is 0.171. The standard deviations of bond length and bond angle from ideality are 0.001 7nm and 2.24° , respectively. The final model of BmK M8 structure is composed of a dense core of secondary structure elements by a stretch of α-helix with two and a half turns (residues 19-28) and a three-stranded antiparallel β-sheet (residues 2-4, 32 - 37, 45- 51). In addition, three loops protruded from the structural core. The general folding properties of BmK M8 molecule were described; a common structure motif which may appear in all scorpion neurotoxins was identified. The conserved aromatic residues and charged residues were found to be distributed on two roughly opposite surfaces of the molecule. The relationship between these two faces and receptor-binding sites are also discussed.
基金National Natural Science Foundation of China and partly by the Grant-in-aid for Overseas Scientific Research from the Ministry of Education, Science and Culture, Japan.
文摘Scorpion anti-insect toxins can be divided into long chain (about 61-70 aminoacid residues)and short chain (about 5 amino acid residues) types according to theirmolecular size, and the former can be further divided into excitatory and depressanttypes on the basis of their pharmacological action. In our previous papers, the iso-lation and determination of the primary structure of an excitatory
基金This Work was respectively supported in part by a grant for Youth Foundation (388008) the National Natural Science Foundation of China and the Grant-in-Aid for Overeas Scientific Reseatrch from the Ministry of Education, Science Culture, Japan
文摘Scorpion venoms contain several kinds of neurotoxins, such as antimammalian neurotoxins, anti-insect neurotoxins and others. But most of them form a family of structurally related single chain proteins of 60—70 amino acid residues and selectively interact with voltage-dependent sodium channels in different excitable cells, only a few minipeptides of 31—39 amino acid residues are proved to block potassium channels. As a kind of molecular probe, scorpion neurotoxins have been widely used for analyzing the
