BACKGROUND： Buthus martensii Karsch is a rare medicinal animal, and dried integral Buthus rnartensii Karsch is an important drug in traditional Chinese medicine. OBJECTIVE： To investigate the effects of scorpion ven...BACKGROUND： Buthus martensii Karsch is a rare medicinal animal, and dried integral Buthus rnartensii Karsch is an important drug in traditional Chinese medicine. OBJECTIVE： To investigate the effects of scorpion venom analgesic active peptide （SAP） extracted from Buthus martensii Karsch on evoked unit discharge of the common peroneal nerve in the posterior nucleus group of the thalamus using a stereotaxic electrophysiological extracellular microelectrode recording. DESIGN, TIME AND SETTING： One-way designed study, performed in the Physiological Laboratory of Shenyang Medical College on September 15, 2006. MATERIALS： Fifty 3-4 months old Wistar rats （25 males and 25 females） were used. SAP was provided by Shenyang Pharmaceutical University. Morphine solution was made by the First Drug Manufactory, Northeastern Drug Manufacture Group （batch number： H20013351）. Naloxone solution was made by Hunan Pharmaceutical Co., Ltd. （batch number： H43021669）. Type ATAC-350 medical data processing equipment was made by the Photoelectricity Company, Japan. METHODS： Fifty rats were randomly divided into the SAP group （n=20）, saline group （n=10）, morphine group （n=10）, or naloxone group （n=10）. In the SAP group, the common peroneal nerve was separated and stimulated with a single square wave （17-19 V intensity; 0.2 ms width; 20 ms retardation time）. Subsequently, SAP （0.01%, 2 μL） was injected into the posterior nucleus group of the thalamus. Rats in the naloxone group were injected with naloxone （1.0 mg/kg i.v.） before SAP injection. Rats in the saline group and the morphine group were injected with saline （2 μL） or morphine （0.01%, 2μL）, respectively, before SAP injection. Other procedures were the same as those in the SAP group. MAIN OUTCOME MEASURES： Evoked discharge in the posterior nucleus group of the thalamus and effects of SAP alone and SAP in combination with saline, morphine, or naloxone on discharges in the posterior nucleus group of the thalamus as measured by TQ-19 medical data processing equipment. RESULTS： SAP group： At 1-3 minutes after SAP injection, evoked discharges in the posterior nucleus group of the thalamus were inhibited, and the inhibitory time lasted for （45.0±0.7） minutes. Saline group： Evoked discharges in the posterior nucleus group of the thalamus did not change after saline injection. Morphine group： At 1-3 minutes after morphine injection, evoked discharges in the posterior nucleus group of the thalamus were inhibited, and the inhibitory time lasted for （35.0±7.8） minutes. Naloxone group： SAP had no effects on evoked potentials in the posterior nucleus group of the thalamus. CONCLUSION： The inhibitory effect of SAP on evoked potentials was superior to that of morphine at the same concentration （2 μL of 0.01% solution）. Naloxone resupination demonstrated that the inhibitory effects of SAP on evoked discharges were influenced by the opioid receptor.展开更多
In order to investigate the cardiovascular effects of the scorpion(Buthus martensiKarsch)venom(BmKv),the left ventricle of the rats was catheterized via the right carotidartery.The LVP,LVEDP,+dp/dt max,Vmax,HR and BP ...In order to investigate the cardiovascular effects of the scorpion(Buthus martensiKarsch)venom(BmKv),the left ventricle of the rats was catheterized via the right carotidartery.The LVP,LVEDP,+dp/dt max,Vmax,HR and BP were observed.The results showedthat intravenous injection of the BmKv(60μg/kg),in comparison with the control,elicited obvi-ous hypertension and increase of cardiac contractility,both of which lasted for 1h,while theheart rate had no significant change rand that pretreating the rats with alpha-adrenergic blocker,phentolamine,antagonized the hypertensive effects,but did not antagonize the increase of cardiaccontractility.Pretreatment with beta-adrenergic blocker,propranolol,has no influence on the ef-fects of the venom.It is suggested that the hypertensive effects are due to the activation of al-pha-adrenergic receptor,whereas the increase of cardiac contractility may not be resulted fromthe activation of beta-adrenergic receptor.The BmKv treated with dithiothreitol before injectionhad no cardiovascular effects,indicating that the intact disulfide bridges play a decisive role inthe cardiovascular effects of the BmKv.展开更多
A novel peptide was purified and characterized from Buthus martensii Karch.The peptide,named BmK M6,is a single-chain polypeptide cross-linked by four intramolecular disulfide bridges.The molecular weight of the pepti...A novel peptide was purified and characterized from Buthus martensii Karch.The peptide,named BmK M6,is a single-chain polypeptide cross-linked by four intramolecular disulfide bridges.The molecular weight of the peptide was determined by MOLDI-TOF-MS as 7034 Da.The partial amino acid sequence of BmK M6 from N-terminal is VRDAYIAKPEN CVYECGITQDCNKLCTENG.展开更多
An insect excitatory toxin gene from Buthus martensii Karseh （BmKIT） was cloned into the expression vector, pET-28a. BmKIT was expressed as inclusion bodies in Eseherichia coli BL21 （DE3） host cells. The authentic...An insect excitatory toxin gene from Buthus martensii Karseh （BmKIT） was cloned into the expression vector, pET-28a. BmKIT was expressed as inclusion bodies in Eseherichia coli BL21 （DE3） host cells. The authenticity of in vitro expressed protein was confirmed by Western blot. The inclusion body protein band in SDS-PAGE was excised and the protein, BmKIT, was extracted. Polyelonal antibodies to the purified protein were raised in rabbits. The antibody reacted specifically with the expressed BmKIT and was used to quantify its presence in transgenic cotton.展开更多
Natural products are the important sources in cardiovascular drug development.In this study,twenty-nine buthutin derivatives were designed,synthesized,and evaluated for their NHE-1 inhibition and protective effects on...Natural products are the important sources in cardiovascular drug development.In this study,twenty-nine buthutin derivatives were designed,synthesized,and evaluated for their NHE-1 inhibition and protective effects on cardiomyo-cyte injury.The structure of the newly synthesized compounds had been confirmed by 1H-NMR,13C-NMR,and HR-ESI-MS spectra.Among all target compounds at 1μM,compounds 9d,9f,9k,9m,and 9n,with a protection ratio exceeding 30%,exerted stronger protective effects on H9c2 cardiomyocyte than positive control dexrazoxane and buthutin A.Meanwhile,compounds 9k,9m,and 9o showed the significant NHE-1 inhibitory activities on H9c2 cardiomyocyte,all with a dpHi/min value less than 0.23.What is more,compounds 9k,9m,9o and buthutin A all exhibited the specificity on NHE-1 inhibition.Molecular modelling studies suggested the ability of compounds 9m and 9o to establish interactions with three hydrogen bonds to Asp267 and Glu346 of NHE-1,but also the ability with much lower CDOCKER energies than positive control cariporide and buthutin A.The structure-activity relationship(SAR)studies suggested that the presences of amide group,four-carbon linker,and para hydroxyl benzene ring were advantageous pharmacophores for above two pharmacological actions.This research would open new avenues for developing amide-guanidine-based cardioprotective agents.展开更多
The insect-selective neurotoxin(BmK IT) of scorpion Buthus martensi Karsch was first reduced and S-alkylated, and then digested by TPCK-trypsin and Staphylococcus aureus V-8 Protease. The enzymatic peptides were purif...The insect-selective neurotoxin(BmK IT) of scorpion Buthus martensi Karsch was first reduced and S-alkylated, and then digested by TPCK-trypsin and Staphylococcus aureus V-8 Protease. The enzymatic peptides were purified on TLC-plastic sheet and submitted to determine their amino acid compositions and sequences. The sequence of the 70 amino acid residues of BmK IT was established with reference to the primary structure of AaH IT, another excitatory insect-selective toxin from the venom of North African scorpion Androctonus australis Hector. About 75% of the homologous sequence was found in the molecules of BmK IT and AaH IT. It is obvious that the results contribute toward better understanding of the molecular structure characteristics, structure/activity relationship of scorpion insect-selective toxins, and they can serve as the molecular basis for utilizing the toxins as a tool to clarify molecular mechanism involved in channel gating, and to infer the possibility of developing them as new selective bioinsecticides.展开更多
During evolution, scorpions have developed the ability to produce a series of toxins. Scorpion toxins, which are reserved in terminal segments of scorpion, serve as the arms for predation and self-defence. They have a...During evolution, scorpions have developed the ability to produce a series of toxins. Scorpion toxins, which are reserved in terminal segments of scorpion, serve as the arms for predation and self-defence. They have also been used as medicine for some human sickness. As far as the targets that they act on are concerned, these toxins can be展开更多
Suitable pattern and high yield were obtained when the reverse-phase performance liquidchromatography (RP-HPLC) was used to separate neurotoxins from venom of Chinese scorpion Buthusmartensi Karsch.Using this techniqu...Suitable pattern and high yield were obtained when the reverse-phase performance liquidchromatography (RP-HPLC) was used to separate neurotoxins from venom of Chinese scorpion Buthusmartensi Karsch.Using this technique,the venom was first separated to two main regions.The toxicitytests show that the insect-selective neurotoxical components are concentrated in the latter region,from whichfive insect-selective neurotoxins designated by BmK IT1-IT5 were obtained.According to the results of thetoxicity test as well as the amino acid composition and N-terminal analyses,BmK IT1 is the excitatory insectneurotoxin as reported in a previous paper,and the others are the newly found depressant insect-selectiveneurotoxins.The molecules of all the four toxins are single-chain minipeptides of about 60 amino acids.Their isoelectric points (pI) are between 8.3 and 8.5.The fact that BmK IT2 loses completely its insect tox-icity after being modified by fluorochrome shows that the positive charges on the molecular surface of thiskind of toxins are important to maintaining the bioactivity of the molecules.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
K+ channel blockers of scorpion venoms are of important value in studyingpharmacology and physiology of specific K+ channel of celis. Based on the amino acid sequences of BmP01 previously characterized as a small-cond...K+ channel blockers of scorpion venoms are of important value in studyingpharmacology and physiology of specific K+ channel of celis. Based on the amino acid sequences of BmP01 previously characterized as a small-conductance Ca2+-activated K+ channel blocker, two 'back to back' degenarate primers have been designed and synthesized for inverse PCR strategy, its full-length cDNA has been cloned from the venom gland of the Chinese scorpion Buthus martensii. The cDNA is composed of 3 parts: 5’ UTR, oRF and 3’ UTR. The flanking sequence of translation initiation codon ATG is AAAKTGA, which is highly conserved in scorpion Na+ channel toxin and protozoan genes, suggesting that these genes may have followed a common mechanism for translation initiation. The 3’ UTR contains poly(A) signal AATAAA. The open reading frame encodes a precursor of 57 residues with a signal peptide of 28 residues and a mature peptide of 29 residues. The signal peptide is rich in hydrophobic amino acid residues and its length is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
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
Martentoxin, a 4,046 Da polypeptide toxin purified from the venom of the scorpion Buthus martensii Karsch, has been demonstrated to block large-conductance Ca2＋-activated K＋ （BKca） channels; however, its biologica...Martentoxin, a 4,046 Da polypeptide toxin purified from the venom of the scorpion Buthus martensii Karsch, has been demonstrated to block large-conductance Ca2＋-activated K＋ （BKca） channels; however, its biological roles are still largely unknown. In the present study, we investigated the pharmacological effects of martentoxin on regulating the production of nitric oxide induced by TNF-a in human umbilical vein endothelial cells （HU- VECs）. We found that, 1, 10 and 100 ~tmol/L martentoxin decreased nitric oxide production by HUVECs ex- posed to 10 ng/mL TNF for 6, 12 and 24 hours. We further demonstrated that martentoxin inhibited the activity of iNOS and retarded the down-regulation of eNOS mRNA induced by TNF-a. Therefore, martentoxin could be a potential therapeutic agent for vascular diseases.展开更多
RYANODINE is a toxic alkaloid from the plant Ryania speciosa Vahl. It selectively binds to the Ca<sup>2+</sup> release channel on skeletal and cardiac heavy sarcoplasmic reticulum （HSR） and has
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
Two non-coding transcripts of toxins were iso-lated from the venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch, named BmαTX15-SP and BmTXKβ-SP, respectively. Analysis of nucleotide sequences s...Two non-coding transcripts of toxins were iso-lated from the venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch, named BmαTX15-SP and BmTXKβ-SP, respectively. Analysis of nucleotide sequences shows that their 5’ sequences are identical to the 5 ’UTR and upstream open reading frame (ORF) sequences of the cDNAs encoding BmαTX15 and BmTXKb, two toxins from Buthus martensii Karsch. But no detectable homology exists in other regions. Two polyadenylated non-coding transcripts encode multiple short ORFs with no more than 34 amino acid resi-dues. The tailing signal (AATAAA) is situated at 14 or 18 bp downstream from the poly(A). The data of genomic se-quences provides support for Bmα TX15-SP and BmTXK β-SP not deriving from splicing errors of pre- mRNAs. Our finding provides evidence for the existence of non-sense-mediated mRNA decay (NMD) pathway in scorpion venom gland cells.展开更多
IN ref.[1],we have described a novel activator(BmK AS)of ryanodine receptor on skeletal muscle,which was obtained from the venom of scorpion Buthus martensi Karsch.This noteprovides the complete amino acid sequence of...IN ref.[1],we have described a novel activator(BmK AS)of ryanodine receptor on skeletal muscle,which was obtained from the venom of scorpion Buthus martensi Karsch.This noteprovides the complete amino acid sequence of the active polypeptide,BmK AS.The molecularweight ot the polypeptide thus determined was 7 698 u,calculated based on its sequence(to-tally 66 residues),which was coincident with the value of 7 696.26 u determined by electro-展开更多
文摘BACKGROUND： Buthus martensii Karsch is a rare medicinal animal, and dried integral Buthus rnartensii Karsch is an important drug in traditional Chinese medicine. OBJECTIVE： To investigate the effects of scorpion venom analgesic active peptide （SAP） extracted from Buthus martensii Karsch on evoked unit discharge of the common peroneal nerve in the posterior nucleus group of the thalamus using a stereotaxic electrophysiological extracellular microelectrode recording. DESIGN, TIME AND SETTING： One-way designed study, performed in the Physiological Laboratory of Shenyang Medical College on September 15, 2006. MATERIALS： Fifty 3-4 months old Wistar rats （25 males and 25 females） were used. SAP was provided by Shenyang Pharmaceutical University. Morphine solution was made by the First Drug Manufactory, Northeastern Drug Manufacture Group （batch number： H20013351）. Naloxone solution was made by Hunan Pharmaceutical Co., Ltd. （batch number： H43021669）. Type ATAC-350 medical data processing equipment was made by the Photoelectricity Company, Japan. METHODS： Fifty rats were randomly divided into the SAP group （n=20）, saline group （n=10）, morphine group （n=10）, or naloxone group （n=10）. In the SAP group, the common peroneal nerve was separated and stimulated with a single square wave （17-19 V intensity; 0.2 ms width; 20 ms retardation time）. Subsequently, SAP （0.01%, 2 μL） was injected into the posterior nucleus group of the thalamus. Rats in the naloxone group were injected with naloxone （1.0 mg/kg i.v.） before SAP injection. Rats in the saline group and the morphine group were injected with saline （2 μL） or morphine （0.01%, 2μL）, respectively, before SAP injection. Other procedures were the same as those in the SAP group. MAIN OUTCOME MEASURES： Evoked discharge in the posterior nucleus group of the thalamus and effects of SAP alone and SAP in combination with saline, morphine, or naloxone on discharges in the posterior nucleus group of the thalamus as measured by TQ-19 medical data processing equipment. RESULTS： SAP group： At 1-3 minutes after SAP injection, evoked discharges in the posterior nucleus group of the thalamus were inhibited, and the inhibitory time lasted for （45.0±0.7） minutes. Saline group： Evoked discharges in the posterior nucleus group of the thalamus did not change after saline injection. Morphine group： At 1-3 minutes after morphine injection, evoked discharges in the posterior nucleus group of the thalamus were inhibited, and the inhibitory time lasted for （35.0±7.8） minutes. Naloxone group： SAP had no effects on evoked potentials in the posterior nucleus group of the thalamus. CONCLUSION： The inhibitory effect of SAP on evoked potentials was superior to that of morphine at the same concentration （2 μL of 0.01% solution）. Naloxone resupination demonstrated that the inhibitory effects of SAP on evoked discharges were influenced by the opioid receptor.
文摘In order to investigate the cardiovascular effects of the scorpion(Buthus martensiKarsch)venom(BmKv),the left ventricle of the rats was catheterized via the right carotidartery.The LVP,LVEDP,+dp/dt max,Vmax,HR and BP were observed.The results showedthat intravenous injection of the BmKv(60μg/kg),in comparison with the control,elicited obvi-ous hypertension and increase of cardiac contractility,both of which lasted for 1h,while theheart rate had no significant change rand that pretreating the rats with alpha-adrenergic blocker,phentolamine,antagonized the hypertensive effects,but did not antagonize the increase of cardiaccontractility.Pretreatment with beta-adrenergic blocker,propranolol,has no influence on the ef-fects of the venom.It is suggested that the hypertensive effects are due to the activation of al-pha-adrenergic receptor,whereas the increase of cardiac contractility may not be resulted fromthe activation of beta-adrenergic receptor.The BmKv treated with dithiothreitol before injectionhad no cardiovascular effects,indicating that the intact disulfide bridges play a decisive role inthe cardiovascular effects of the BmKv.
文摘A novel peptide was purified and characterized from Buthus martensii Karch.The peptide,named BmK M6,is a single-chain polypeptide cross-linked by four intramolecular disulfide bridges.The molecular weight of the peptide was determined by MOLDI-TOF-MS as 7034 Da.The partial amino acid sequence of BmK M6 from N-terminal is VRDAYIAKPEN CVYECGITQDCNKLCTENG.
基金the National Natural Science Foundation of China(No30670282 and 30470239)Natural Science Foundation of Shanxi Province(20051065 and 20041033)Scholar Foundation of Shanxi Province
文摘An insect excitatory toxin gene from Buthus martensii Karseh （BmKIT） was cloned into the expression vector, pET-28a. BmKIT was expressed as inclusion bodies in Eseherichia coli BL21 （DE3） host cells. The authenticity of in vitro expressed protein was confirmed by Western blot. The inclusion body protein band in SDS-PAGE was excised and the protein, BmKIT, was extracted. Polyelonal antibodies to the purified protein were raised in rabbits. The antibody reacted specifically with the expressed BmKIT and was used to quantify its presence in transgenic cotton.
基金supported by the National Natural Science Foundation of China(NSFC)Youth Project(No.82204397).
文摘Natural products are the important sources in cardiovascular drug development.In this study,twenty-nine buthutin derivatives were designed,synthesized,and evaluated for their NHE-1 inhibition and protective effects on cardiomyo-cyte injury.The structure of the newly synthesized compounds had been confirmed by 1H-NMR,13C-NMR,and HR-ESI-MS spectra.Among all target compounds at 1μM,compounds 9d,9f,9k,9m,and 9n,with a protection ratio exceeding 30%,exerted stronger protective effects on H9c2 cardiomyocyte than positive control dexrazoxane and buthutin A.Meanwhile,compounds 9k,9m,and 9o showed the significant NHE-1 inhibitory activities on H9c2 cardiomyocyte,all with a dpHi/min value less than 0.23.What is more,compounds 9k,9m,9o and buthutin A all exhibited the specificity on NHE-1 inhibition.Molecular modelling studies suggested the ability of compounds 9m and 9o to establish interactions with three hydrogen bonds to Asp267 and Glu346 of NHE-1,but also the ability with much lower CDOCKER energies than positive control cariporide and buthutin A.The structure-activity relationship(SAR)studies suggested that the presences of amide group,four-carbon linker,and para hydroxyl benzene ring were advantageous pharmacophores for above two pharmacological actions.This research would open new avenues for developing amide-guanidine-based cardioprotective agents.
基金This research was supported by a fellowship from CNRS of France, granted to Ji Yong-hua,and in part by a grant for Youth Foundation(388008), the National Natural Science Foundation of China and the Grant-in-Aid for Overseas Scientific Research from the M
文摘The insect-selective neurotoxin(BmK IT) of scorpion Buthus martensi Karsch was first reduced and S-alkylated, and then digested by TPCK-trypsin and Staphylococcus aureus V-8 Protease. The enzymatic peptides were purified on TLC-plastic sheet and submitted to determine their amino acid compositions and sequences. The sequence of the 70 amino acid residues of BmK IT was established with reference to the primary structure of AaH IT, another excitatory insect-selective toxin from the venom of North African scorpion Androctonus australis Hector. About 75% of the homologous sequence was found in the molecules of BmK IT and AaH IT. It is obvious that the results contribute toward better understanding of the molecular structure characteristics, structure/activity relationship of scorpion insect-selective toxins, and they can serve as the molecular basis for utilizing the toxins as a tool to clarify molecular mechanism involved in channel gating, and to infer the possibility of developing them as new selective bioinsecticides.
基金The sequences have been deposited in EMBL Bank with Accession Nos. X92077 & X92846.
文摘During evolution, scorpions have developed the ability to produce a series of toxins. Scorpion toxins, which are reserved in terminal segments of scorpion, serve as the arms for predation and self-defence. They have also been used as medicine for some human sickness. As far as the targets that they act on are concerned, these toxins can be
基金Project supported by a grant from Youth Foundation (388008) to Ji Yong-hua from the National Natural Science Foundation of China and the grant-in-aid for overseas scientific research from the Ministry of Education,Science and Culture,Japan.
文摘Suitable pattern and high yield were obtained when the reverse-phase performance liquidchromatography (RP-HPLC) was used to separate neurotoxins from venom of Chinese scorpion Buthusmartensi Karsch.Using this technique,the venom was first separated to two main regions.The toxicitytests show that the insect-selective neurotoxical components are concentrated in the latter region,from whichfive insect-selective neurotoxins designated by BmK IT1-IT5 were obtained.According to the results of thetoxicity test as well as the amino acid composition and N-terminal analyses,BmK IT1 is the excitatory insectneurotoxin as reported in a previous paper,and the others are the newly found depressant insect-selectiveneurotoxins.The molecules of all the four toxins are single-chain minipeptides of about 60 amino acids.Their isoelectric points (pI) are between 8.3 and 8.5.The fact that BmK IT2 loses completely its insect tox-icity after being modified by fluorochrome shows that the positive charges on the molecular surface of thiskind of toxins are important to maintaining the bioactivity of the molecules.
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
文摘K+ channel blockers of scorpion venoms are of important value in studyingpharmacology and physiology of specific K+ channel of celis. Based on the amino acid sequences of BmP01 previously characterized as a small-conductance Ca2+-activated K+ channel blocker, two 'back to back' degenarate primers have been designed and synthesized for inverse PCR strategy, its full-length cDNA has been cloned from the venom gland of the Chinese scorpion Buthus martensii. The cDNA is composed of 3 parts: 5’ UTR, oRF and 3’ UTR. The flanking sequence of translation initiation codon ATG is AAAKTGA, which is highly conserved in scorpion Na+ channel toxin and protozoan genes, suggesting that these genes may have followed a common mechanism for translation initiation. The 3’ UTR contains poly(A) signal AATAAA. The open reading frame encodes a precursor of 57 residues with a signal peptide of 28 residues and a mature peptide of 29 residues. The signal peptide is rich in hydrophobic amino acid residues and its length is
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
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supported by the National Science Foundation of China(No.30271137No.30771831+1 种基金No.81072329)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Martentoxin, a 4,046 Da polypeptide toxin purified from the venom of the scorpion Buthus martensii Karsch, has been demonstrated to block large-conductance Ca2＋-activated K＋ （BKca） channels; however, its biological roles are still largely unknown. In the present study, we investigated the pharmacological effects of martentoxin on regulating the production of nitric oxide induced by TNF-a in human umbilical vein endothelial cells （HU- VECs）. We found that, 1, 10 and 100 ~tmol/L martentoxin decreased nitric oxide production by HUVECs ex- posed to 10 ng/mL TNF for 6, 12 and 24 hours. We further demonstrated that martentoxin inhibited the activity of iNOS and retarded the down-regulation of eNOS mRNA induced by TNF-a. Therefore, martentoxin could be a potential therapeutic agent for vascular diseases.
文摘RYANODINE is a toxic alkaloid from the plant Ryania speciosa Vahl. It selectively binds to the Ca<sup>2+</sup> release channel on skeletal and cardiac heavy sarcoplasmic reticulum （HSR） and has
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This work was supported by the National Natural Science Foundation of China (Grant No. 39970897).
文摘Two non-coding transcripts of toxins were iso-lated from the venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch, named BmαTX15-SP and BmTXKβ-SP, respectively. Analysis of nucleotide sequences shows that their 5’ sequences are identical to the 5 ’UTR and upstream open reading frame (ORF) sequences of the cDNAs encoding BmαTX15 and BmTXKb, two toxins from Buthus martensii Karsch. But no detectable homology exists in other regions. Two polyadenylated non-coding transcripts encode multiple short ORFs with no more than 34 amino acid resi-dues. The tailing signal (AATAAA) is situated at 14 or 18 bp downstream from the poly(A). The data of genomic se-quences provides support for Bmα TX15-SP and BmTXK β-SP not deriving from splicing errors of pre- mRNAs. Our finding provides evidence for the existence of non-sense-mediated mRNA decay (NMD) pathway in scorpion venom gland cells.
文摘IN ref.[1],we have described a novel activator(BmK AS)of ryanodine receptor on skeletal muscle,which was obtained from the venom of scorpion Buthus martensi Karsch.This noteprovides the complete amino acid sequence of the active polypeptide,BmK AS.The molecularweight ot the polypeptide thus determined was 7 698 u,calculated based on its sequence(to-tally 66 residues),which was coincident with the value of 7 696.26 u determined by electro-
