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 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
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
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.
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.
