| comparison of the hemolytic activity and solution structures of two snake venom cardiotoxin analogues which only differ in their n-terminal amino acid. | cardiotoxin analogues iv (ctx iv) and ii (ctx ii) isolated from the venom of taiwan cobra (naja naja atra) differ in their amino acid sequence by a single amino acid at the n-terminal end. leucine at the n-terminal end in ctx ii is replaced by arginine in ctx iv. ctx iv is an unique snake venom cardiotoxin as it is the only cardiotoxin isoform known so far which possesses a positively charged residue at the n-terminal amino acid. all other cardiotoxins have a hydrophobic amino acid (leucine or i ... | 1997 | 9398182 |
| the amino acid sequences of two postsynaptic neurotoxins isolated from malayan cobra (naja naja sputatrix) venom. | the complete amino acid sequences of two postsynaptic neurotoxins (toxin-3 and toxin-5) isolated from malayan cobra (naja naja sputatrix) venom were determined by direct automated edman degradation of peptides obtained from digests with various proteases. toxin-3 and toxin-5 are both short-chain neurotoxins and their amino acid sequences are highly homologous to naja naja atra and naja naja philippinensis neurotoxin, respectively. toxin-3 is unique in possessing aspartic acid (d) as the fifth re ... | 1994 | 7886703 |
| specificity of helix-induction by 2,2,2-trifluoroethanol in polypeptides. | the specificity of helix-induction in polypeptides by 2,2,2-trifluoro ethanol (tfe) is studied using an all beta-sheet protein such as cardiotoxin analogue i (ctx i) from the taiwan cobra (naja naja atra) and a homopolymer such as poly-l-lysine. it is found that alcohols including tfe can 'non-specifically' induce helix at high concentrations both in ctx i and polylysine at neutral ph. however, among the alcohols used, only tfe could transform the heat-induced beta-sheet conformation of polylysi ... | 1997 | 9352368 |
| action of taiwan cobra cardiotoxin on membranes: binding modes of a beta-sheet polypeptide with phosphatidylcholine bilayers. | the interaction of taiwan cobra cardiotoxin (ctx a3), a basic polypeptide consisting of three-fingered loops and five-strand beta-sheet structure, with zwitterionic dipalmitoylphosphatidylcholine (dppc) has been studied by 31p and 2h nmr to understand the binding modes of ctx in membrane bilayers. the results, in conjunction with dph fluorescence anisotropy and differential scanning calorimetry studies, show that ctx may penetrate and lyse the bilayers into small aggregates at a lipid/protein mo ... | 1997 | 9245415 |
| the action of taiwan cobra venom on methionine enkephalin: a useful assay for oligopeptidase content. | the pentapeptide methionine enkephalin is readily hydrolysed by the oligopeptidase activity contained in taiwan cobra (naja naja atra) venom. it is a significantly better substrate than the peptides previously used to identify the presence of this enzyme, but it retains many of the sequence characteristics shared by these other peptides. analysis of the manner of hydrolysis by means of high-performance liquid chromatography and electrospray mass spectrometry revealed the simultaneous actions of ... | 1997 | 9248009 |
| cdna sequence analysis of cardiotoxin variants from taiwan cobra. | five cdnas encoding cardiotoxin variants were constructed from the cellular rna isolated from the venom glands of naja naja atra by reverse transcription-polymerase chain reaction. a high degree of nucleotide sequence homology was observed between these variants and other determined ones. among them, a novel cardiotoxin 6 had 61 amino acid residues rather than 60 ones that usually observed with naja naja atra cardiotoxins. the other cardiotoxin variants were the homologues of cardiotoxins 1, v o ... | 1997 | 9192088 |
| the role of the n-terminal leucine residue in snake venom cardiotoxin ii (naja naja atra). | the n-terminal leucine residue of snake venom cardiotoxin ii (ctx ii) (naja naja atra) was systematically replaced with d-leucine (ctxii-l1-d-l), glycine (ctxii-l1g) or deleted [ctxii-(2-60)] to study the role of leucine residue in ctx ii molecule. ctx ii, ctxl1-d-l, ctxl1g and ctx(2-60) were produced by chemical synthesis method and purified by high performance liquid chromatography. owing to folding problem in ctxii-(2-60), only ctx ii, ctxii-l1-d-l and ctxii-l1g were produced in a pure form a ... | 1997 | 9168920 |
| non-specific helix-induction in charged homopolypeptides by alcohols. | the specificity/non-specificity of helix-induction in charged homopolymers such as polylysine and polyglutamic acid, at neutral ph, by various alcohols namely 2,2,2-trifluoroethanol (tfe), methanol, ethanol and 1-propanol is studied. it is found that all the alcohols used, non-specifically induced helical conformation at high concentrations. in addition, the effect(s) of tfe on an all beta-sheet protein, such cardiotoxin analogue i (ctx i) from the taiwan cobra (naja naja atra) is also studied. ... | 1997 | 9074617 |
| crystal structure of cardiotoxin v from taiwan cobra venom: ph-dependent conformational change and a novel membrane-binding motif identified in the three-finger loops of p-type cardiotoxin. | the crystal structure of cardiotoxin v from taiwan cobra venom (ctx a5) has been solved at ph 8.5 and refined to an r-factor of 20.7% for 7013 reflections [>2sigma(f)] between 8- and 2.19-a resolution. the refined model shows that ctx a5 exists as a dimer. the assembly consists of 974 non-hydrogen atoms from 124 residues and 73 water molecules. the global monomeric structure is similar to that determined by nmr at ph 3.7, characterized by a core formed by two beta-sheets connected with three-fin ... | 1997 | 9054545 |
| heparin and heparan sulfate bind to snake cardiotoxin. sulfated oligosaccharides as a potential target for cardiotoxin action. | cardiotoxins (ctxs) from cobra venom show cytotoxicity toward several cell types. they cause systolic heart arrest and severe tissue necrosis. their interaction with phospholipids is established but by itself fails to explain the specificity of these toxins; other component(s) of membrane must, therefore, intervene to direct them toward their target. we herein show, for the first time, that sulfated glycosaminoglycans, heparin, heparan sulfate (hs), chondroitin sulfate (cs), and dermatan sulfate ... | 1997 | 8999818 |
| characterization of a partially structured state in an all-beta-sheet protein. | cardiotoxin analogue iii (ctx iii) is a low-molecular-mass all-beta-sheet protein isolated from the taiwan cobra (naja naja atra) venom. a stable partially structured state similar to the "molten globule' state has been identified for ctx iii in a 3% (w/v) solution of 2,2,2-trichloroacetic acid at 298 k. this stable state has been structurally characterized using a variety of techniques such as cd, 1-anilinonaphthalene-8-sulphonate fluorescence binding, fourier transform ir and two-dimensional n ... | 1997 | 9020881 |
| probing calcium ion-induced conformational changes of taiwan cobra phospholipase a2 by trinitrophenylation of lysine residues. | phospholipase a2 (pla2) from naja naja atra (taiwan cobra) snake venom was subjected to lysine modification with trinitrobenzene sulfonate (tnbs). three major derivatives, tnp-1, tnp-2, and tnp-3, were separated by high-performance liquid chromatography (hplc) from the reaction mixtures in the absence of ca2+. however, only tnp-2 and tnp-3 were isolated when trinitrophenylated reaction was carried out in the presence of ca2+. tnp-1 and tnp-2 contained only one tnp group, on lys-65 and lys-6, res ... | 1997 | 9055207 |
| destabilisation of native tertiary structural interactions is linked to helix-induction by 2,2,2-trifluoroethanol in proteins. | the effect of 2,2,2-trifluoroethanol (tfe) on the structure of an all beta-sheet protein, cardiotoxin analogue 111 (ctx iii) from the taiwan cobra (naja naja atra) is studied. it is found that high concentrations (> 80% v/v) of tfe induced a beta-sheet to alpha-helix structural transition. it is found that in denatured and reduced ctx iii (rctx iii) helical conformation is induced even upon addition of low concentrations (> 10% v/v) of tfe. using three other proteins, namely, ribonuclease a (rna ... | 1996 | 9024898 |
| induction of helical conformation in all beta-sheet proteins by trifluoroethanol. | the effect of 2,2,2-trifluoroethanol (tfe) on the structure of five all beta-sheet proteins, isolated from the venom of the taiwan cobra (naja naja atra), is studied. in all the toxins used, it is observed that significant amount of alpha-helix is induced at higher concentrations of tfe. in all these proteins, the induction of helical conformation and disruption of the tertiary structure seem to occur simultaneously. the structural transitions induced by tfe in reduced and denatured protein appe ... | 1996 | 9016415 |
| the essentiality of calcium ion in the enzymatic activity of taiwan cobra phospholipase a2. | in order to address the mechanism whereby ca2+ wad crucial for the manifestation of the enzymatic activity of phospholipase a2 (pla2), four divalent cations were used to assess their influences on the catalytic activity and the fine structures of naja naja atra pla2. it was found that substitution of mg2+ or sr2+ for ca2+ in the substrate solution caused a decrease in the pla2 activity to 77.5% or 54.5%, respectively, of that in the presence of ca2+. however, no pla2 activity was observed with t ... | 1996 | 9008293 |
| modification of tyrosine-3 (63) and lysine-6 of taiwan cobra phospholipase a2 affects its ability to enhance 8-anilinonaphthalene-1-sulfonate fluorescence. | the tyr-3 (63) and lys-6 of naja naja atra phospholipase a2 (pla2) were modified with p-nitrobenzenesulfonyl fluoride and 4-chloro-3,5-dinitrobenzoate, respectively. although the ability of the lys-modified derivative to enhance the ans fluorescence was lower than that observed with native pla2, the ans-binding affinity of the lys-modified derivative was similar to that of the native enzyme. modifications on tyr-3 or/and tyr-63 of pla2 resulted in the complete loss of its ability to enhance the ... | 1996 | 8896745 |
| the role of acidic amino acid residues in the structural stability of snake cardiotoxins. | we have recently shown that membrane-related activities of cardiotoxin v from naja naja atra (ctx a5) are diminished at acidic ph although the overall beta-sheet structure of the molecule is maintained. in order to understand more about the mechanism of inactivation of ctx at acidic ph, we studied the effect of ph and denaturing reagents on the structural stability of ctx. we found, first, ph-induced structural transitions occurred in ctx a5 at two ph values as judged by the cd ellipticity aroun ... | 1996 | 8703923 |
| conformational change and inactivation of membrane phospholipid-related activity of cardiotoxin v from taiwan cobra venom at acidic ph. | the phospholipid binding activity of cardiotoxin v from naja naja atra (ctx a5) was studied by use of langmuir monolayers and found to exhibit ph-dependence in binding to phosphatidylcholine membrane with an apparent pka around 6.0. proton nmr investigation of the ctx a5 molecule in the presence of phosphatidylcholine micelles reveals a decrease in association of ctx a5 with membranes at low ph as a result of the protonation of his-4 near the membrane binding site of loop i region of ctx. the ph ... | 1996 | 8703922 |
| thermal denaturation of an all beta-sheet protein--identification of a stable partially structured intermediate at high temperature. | the thermal unfolding of an all beta-sheet protein, cardiotoxin analogue iii, from the taiwan cobra (naja naja atra) is studied at ph 2.0, 4.0 and 6.0. at ph 4.0, using circular dichroism and 1-anilino naphthalene-8-sulphonic acid (ans) fluorescence binding studies, a stable partially structured intermediate is detected at 90 degrees c. | 1996 | 8739135 |
| effect of chaotropic denaturant on the binding of 1-anilino-8-naphthalene sulfonic acid to proteins. | 1-anilino-8-naphthalene sulfonic acid (ans), a hydrophobic dye, is widely used to monitor conformational changes occurring in proteins during their folding/unfolding. using cardiotoxin iii (whose conformation remains unperturbed even in 6 m urea) from the taiwan cobra (naja naja atra) venom, it is demonstrated that chaotropic denaturant such as urea directly competes with the interaction between ans and the protein. the results presented in this report, in our opinion, has significant implicatio ... | 1996 | 8645725 |
| 2,2,2-trifluoroethanol induces helical conformation in an all beta-sheet protein. | the effect of 2,2,2-trifluoroethanol (tfe) on the structure of an all beta-sheet protein, cardiotoxin analogue ii (ctx ii), from the taiwan cobra (naja naja atra) is studied. using circular dichroism studies, it is found that higher concentrations of tfe induced a structural transition from beta-sheet to alpha-helix, both in the native state (nctx ii) and in denatured but not disulfide reduced ctx ii (dctx ii) samples. the beta-sheet to alpha-helix conversion is shown to be cooperative. however, ... | 1996 | 8630070 |
| the interaction of 8-anilinonaphthalene-1-sulfonate with his-47 of taiwan cobra phospholipase a2 perturbing by the binding of calcium ion. | the 8-anilinonaphthalene-1-sulfonate (ans) fluorescence intensity of ans-naja naja atra (taiwan cobra) phospholipase a2 (pla2) complex increased with the addition of ca2+, but the observed fluorescence enhancement markedly decreased after methylation of his-47 in pla2 molecule. however, the binding affinities of methylated pla2 for ans and ca2+ were similar to or even greater than those observed with native pla2. these results, together with the finding that ans electrostatically interacted with ... | 1996 | 8799461 |
| the essentiality of his-47 and the n-terminal region for the binding of 8-anilinonaphthalene-1-sulfonate with taiwan cobra phospholipase a2. | the binding of the apolar fluorescent dye 8-anilinonaphthalene-1-sulfonate (ans) to naja naja atra phospholipase a2 (pla2) as well as the enhancement of ans fluorescence of the pla2-ans complex decreased with increasing ph in a ph range from 3 to 9. these ph-dependent curves can be well interpreted as the perturbation of an ionizable group with pk value of 5.8, which was assigned as his-47 in the active site of pla2. the ionizable group with pk 5.8 was no longer observed after methylation of his ... | 1996 | 8804572 |
| a case study of cardiotoxin iii from the taiwan cobra (naja naja atra). solution structure and other physical properties. | | 1996 | 8726052 |
| analysis of a conformation-independent epitope and a conformational epitope in a protein: a study on cobrotoxin from taiwan cobra venom. | the antibodies against cobrotoxin were separated into two antibody preparations by successive affinity chromatographies on reduced and s-carboxymethylated (rcm)-cobrotoxin-sepharose, and cobrotoxin-sepharose columns. the antibodies (abbreviated as abcf-i) that bound with the rcm-cobrotoxin-sepharose were verified to specifically recognize the continuous epitopes of cobrotoxin, which were insensitive to conformational changes. whilst the antibodies (abbreviated as abcf-d) that did not bind with t ... | 1995 | 7592551 |
| identification of 'molten globule'-like state in all beta-sheet protein. | the cardiotoxin analogue iii (ctx iii), isolated from the taiwan cobra venom (naja naja atra), is a sixty amino acid, all beta-sheet protein. the 2,2,2-trifluoro ethanol (tfe) induced unfolding of ctx iii is studied under acidic conditions (ph 2.5). using circular dichroism, 1-anilino-8-napthalene sulphonic acid binding and nmr experiments, it is shown that stable, partially structured state(s) ['molten globule'-like state] is formed between 50 and 80% tfe concentrations. the protein was found t ... | 1995 | 7864840 |
| cardiotoxin ii from taiwan cobra venom, naja naja atra. structure in solution and comparison among homologous cardiotoxins. | the three-dimensional structure in solution of cardiotoxin ii, a membrane toxin from the venom of taiwan cobra, naja naja atra, was determined using 1h nuclear magnetic resonance spectroscopy and molecular modeling based on the hybrid distance geometry/dynamic simulated annealing technique. a complete sequence-specific proton assignment was obtained, and the secondary structures of the protein were determined from information on nuclear overhauser effect connectivities, coupling constants, and h ... | 1994 | 8089116 |
| structure of cobra cardiotoxin ctx i as derived from nuclear magnetic resonance spectroscopy and distance geometry calculations. | the structure of cardiotoxin ctx i from naja naja atra has been investigated by nmr spectroscopy. sequence specific resonance assignments have been obtained for all backbone protons as well as for most side-chain protons. distance geometry calculations were carried out using a metric matrix dg program. a total of 715 noe constraints, 27 phi angle constraints and a list of the hydrogen bond donors were used for the metric matrix dg calculations and refinement. the average pairwise r.m.s.d. of the ... | 1994 | 8046750 |
| zinc and barium inhibit the phospholipase a2 from naja naja atra by different mechanisms. | the mode of inhibition of the phospholipase a2 (pla2) enzyme from the chinese cobra (naja naja atra) by zn2+ is qualitatively different from inhibition by ba2+. inhibition by ba2+ shows the kinetic characteristics of a conventional competitive inhibitor acting to displace ca2+ from a single essential site, but zn2+ has the paradoxical property of being more inhibitory at high than at low ca2+ concentration. kinetic analysis of the ca(2+)-dependence of enzymic activity shows a bimodal response, i ... | 1994 | 8042995 |
| two distinct types of cardiotoxin as revealed by the structure and activity relationship of their interaction with zwitterionic phospholipid dispersions. | cardiotoxins (ctxs) are a group of homologous proteins found in cobra snake venom and consist of 60-62 amino acid residues. although ctxs are known to consist of three extended beta-sheet loops similar to neurotoxins, the target and interaction of ctxs with membranes unlike those of neurotoxins are not well understood. herein, we report comparative studies of 10 ctxs purified from taiwan cobra (naja naja atra) and mozambique spitting cobra (naja mossambica mossambica) snake venoms with respect t ... | 1994 | 8182052 |
| cardiotoxin iii from the taiwan cobra (naja naja atra). determination of structure in solution and comparison with short neurotoxins. | the structure in solution of cardiotoxin iii, a membrane toxin purified from the venom of the taiwan cobra, naja naja atra, is reported. sequence-specific assignment of 1h-nmr lines was completed and the nmr data show the presence of a triple and a double-stranded antiparallel beta-sheet. many noe cross peaks identified in noesy spectra were applied as distance constraints based on a hybrid distance geometry/dynamical simulated annealing technique; 20 structures were found within a single family ... | 1994 | 8308891 |
| sequence characterization of cardiotoxins from taiwan cobra: isolation of a new isoform. | cardiotoxins (or called cytotoxins) are a group of very basic polypeptides present in some snake venoms, which are especially abundant in formosan cobras. several cardiotoxins with distinct pharmacological and biochemical properties were isolated and purified from the taiwan cobra venom (naja naja atra) by employing sequentially preparative-scale cation-exchange chromatography on tsk cm-650 coupled with the improved separation of toxin components on reversed-phase hplc based on their hydrophobic ... | 1993 | 8193587 |
| identification of functional involvement of tryptophan residues in phospholipase a2 from naja naja atra (taiwan cobra) snake venom. | phospholipase a2 (pla2) from naja naja atra snake venom was subjected to trp modification with 2-nitrophenylsulfenyl chloride (nps-cl), and six derivatives were separated by hplc. the results of amino-acid analysis and sequence determination revealed that trp-18, trp-19 and trp-61 were modified by nps-cl. the order of accessibilities of the three trp residues for nps-cl was trp-18 > trp-19 > trp-61. sulfenylation of trp-18 caused a 92% drop in enzymatic activity. modification of trp-19 and trp-6 ... | 1993 | 8399382 |
| characteristics of the peptidase activity contained in taiwan cobra (naja naja atra) venom. | cobra venoms (naja species) contain a little-understood peptidase activity which shows specificity towards small peptides containing glycine and non-polar aromatic/aliphatic residues. we have examined the ability of whole cobra venom to degrade several types of peptide with emphasis on the action of taiwan cobra (naja naja atra) venom on l-alanylglycylglycine and glycylglycyl-l-phenylalanine. these are competing substrates, and it proved possible to generate inhibitors of the degradation of glyc ... | 1993 | 8303723 |
| solution structure of cardiotoxin v from naja naja atra. | cardiotoxins are small proteins that are found in the venoms of snakes from the elapidae family. these toxins are known to bind to and disrupt the organization, integrity, and function of the cell membrane. most of the well-studied cardiotoxins cause depolarization of membrane potentials and/or lysis of red cells. in contrast, ctx v from naja naja atra displays poor hemolytic activity but is proficient at inducing aggregation and fusion of sphingomyelin vesicles [chien et al. (1991) j. biol. che ... | 1993 | 8347605 |
| structural analysis and comparison of cobrotoxin and cardiotoxins by near-ir fourier transform raman spectroscopy. | venom toxins were isolated from formosan cobra (naja naja atra) by cation-exchange chromatography. the near-ir ft-raman analytical method has been applied to the characterization and classification of the toxin components in their lyophilized forms. structural analysis and comparison of various purified toxin fractions were made with respect to their amino acid compositions and near-ir fourier-transform raman spectra. the results indicate that the major secondary structure of cobra toxins includ ... | 1992 | 1610379 |
| assessment of the role of tryptophan residues in phospholipase a2 by fluorescence quenching. | tryptophan (trp) fluorescence of two phospholipases a2 (pla2) from naja naja atra and naja nigricollis snake venoms was quenched by acrylamide and iodide. trp residues in n. naja atra pla2 were equally accessible to acrylamide and iodide. iodide quenching studies indicate that there are two classes of trp fluorophores in n. nigricollis cms-9. the accessible class consists of trp-18 and trp-19. removal of the n-terminal octapeptide caused a perturbation of the micro-environment of the trp residue ... | 1989 | 2489051 |
| lipid-induced changes in the secondary structure of snake venom cardiotoxins. | the secondary structures of three snake venom cardiotoxins (from hemachatus hemachatus, naja naja atra, and naja naja naja), in aqueous solution and in a lipid-bound form, were investigated by fourier-transform infrared spectroscopy. the conformation-sensitive protein infrared bands in the amide i region were analyzed using deconvolution and band-fitting procedures. the spectra of the three cardiotoxins in aqueous buffer are very similar; they indicate a high content of both antiparallel beta-sh ... | 1988 | 3335526 |
| tryptophan residue essential for activity of naja naja atra phospholipase a2. | when naja naja atra phospholipase a2, which contains three tryptophan residues at the 18th, 19th, and 61st positions, was oxidized with n-bromosuccinimide at ph 4.0, its activity decreased in a convex manner with increase in the extent of oxidation of tryptophan residues. the curve shape showed that the tryptophan residue oxidized last is most responsible for the activity. the order of accessibilities of the three tryptophan residues, which was analyzed according to the method reported previousl ... | 1988 | 3360757 |
| role of the n-terminal region in phospholipases a2 from naja naja atra (taiwan cobra) and naja nigricollis (spitting cobra) venoms. | the n-terminal alpha-amino groups of two phospholipases a2 (pla2) from naja naja atra and naja nigricollis venoms were selectively modified with trinitrobenzene sulfonic acid, and the modified derivatives were separated by high performance liquid chromatography (hplc). trinitrophenylated (tnp) derivatives contained only one tnp group in the alpha-amino group of asn-1 and showed a marked decrease in enzymatic activity. pla2 enzymes were cleaved with cnbr, and the n-terminal octapeptide was separa ... | 1988 | 3188062 |
| depolarization of skeletal muscle cells in culture by a cardiotoxin-like basic polypeptide from the venom of the taiwan cobra (naja naja atra). | a cardiotoxin-like basic polypeptide from the venom of naja naja atra is homologous to cardiotoxins from the same venom, but much less toxic. to determine if it acts like the cardiotoxins its depolarizing ability was measured. it was about 10 times less potent than the cardiotoxins. five amino acids are conserved in the sequences studied, on the exposed second and third loops of the toxin backbone. they may be part of the toxins' interactive site. | 1987 | 3629619 |
| crystallographic studies of snake venom proteins from taiwan cobra (naja nana atra). cardiotoxin-analogue iii and phospholipase a2. | orthorhombic crystals of cardiotoxin-analogue iii from taiwan cobra have been grown from 2-methyl-2,4-pentanediol solution. the space group is p222 with 2 molecules/asymmetric unit. several different crystal forms of phospholipase a2 from taiwan cobra have been produced with or without ca2+ ion. one of them, grown from 30 mm sodium cacodylate buffer (ph 6 to 7) and 30% 2-methyl-2,4-pentanediol with 20 mg/ml of protein, diffracts well to 2 a resolution. it crystallizes in space group p3112 or p32 ... | 1981 | 7263715 |
| complete amino acid sequence of a phospholipase a2 from the venom of naja naja atra (taiwan cobra). | | 1981 | 7222082 |
| chemical modification of lysine and histidine residues in phospholipase a2 from the venom of naja naja atra (taiwan cobra). | | 1981 | 6795761 |
| annual cycles in levels of pituitary and plasma gonadotropin, gonadal steroids, and thyroid activity in the chinese cobra (naja naja). | | 1980 | 7461439 |
| purification and characterization of anti-cholinesterase factor from the venom of naja naja atra. | the anti-cholinesterase factor from naja naja atra venom was purified by means of successive column chromatography on sephadex g-75, carboxymethyl-cellulose and hydroxyapatite. the purified anti-cholinesterase factor was homogeneous by sodium dodecyl sulfate polyacrylamide gel electrophoresis. the molecular weight was estimated to be approx. 50 000. the isoelectric point was determined to be 6.8. this factor was found to be the first cholinesterase inhibitor protein. we have called this anti-cho ... | 1980 | 7397218 |
| amino acid sequence of a less-cytotoxic basic polypeptide (lcbp) isolated from the venom of the indian cobra (naja naja). | a less-cytotoxic polypeptide, designated as lcbp, was isolated from the venom of naja naja by gel filtration on sephadex g-50 followed by cm-cellulose chromatography. the cytotoxicity toward yoshida sarcoma cells and lethal toxicity toward mice of lcbp were both one order of magnitude lower than that of cytotoxins and that of toxin a, respectively. lcbp is a single polypeptide consisting of 61 amino acid residues with four intramolecular disulfide linkages, and the amino acid sequence is the sam ... | 1987 | 3566773 |
| kinetics of the hydrolysis of micellar substrates catalyzed by snake venom phospholipases a2. | effects of ca2+ on the kinetic parameters for the hydrolysis of mixed micelles of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine (dic16pc) with triton x-100, catalyzed by a cobra (naja naja atra) (group i) and a habu (trimeresurus flavoviridis) (group ii) pla2s, were studied and compared with the results reported for other group i and ii enzymes. the substrate bindings to group i enzymes were independent of the ca2+ binding, whereas the substrate bindings to group ii enzymes were facilitated mor ... | 1992 | 1569045 |
| characterization and immunological comparison of isoenzymes of phospholipases a2 from snake venoms of different genera and families. | phospholipases a2 (pla2) were isolated and purified from the taiwan cobra (naja naja atra) and several snake species of the same or different genera by semipreparative cation-exchange and reversed-phase hplc. they were shown to possess different enzymatic activity toward the synthetic substrate l-alpha-lecithin by the fatty-acid titration method. the immunological cross-reactivity of these structurally similar isotoxins was investigated using immunodiffusion, precipitin reaction and enzyme-linke ... | 1991 | 1810246 |
| structural analysis of phospholipase a2 by near-ir fourier transform raman spectroscopy. | venom toxins were isolated from formosan cobra (naja naja atra) by cation-exchange chromatography. most toxin components could be obtained in relatively pure forms by single-step ion-exchange chromatography whereas an extra step of gel permeation was needed for the separation of phospholipase a2 (pla2) from the major neurotoxic component, i.e. cobrotoxin. the newer near-ir ft-raman analytical method has been applied to the characterization of pla2 in their lyophilized forms. structural analysis ... | 1991 | 1789801 |
| preliminary crystallographic analysis of cardiotoxin v with major fusion activity from taiwan cobra (naja naja atra) venom. | crystals of a cardiotoxin from taiwan cobra venom have been obtained by the vapor diffusion method using methyl pentanediol as precipitant. the crystals belong to the hexagonal space group p6(1)22 (or p6(5)22), with cell dimensions a = b = 47.5 a, c = 111.3 a, alpha = beta = 90 degrees and gamma = 120 degrees and diffract to a resolution of 2.2 a. there is one molecule per asymmetric unit and the solvent content is estimated to be 53%. | 1991 | 2056526 |
| a convenient method to differentiate the monoclonal antibodies with differing immunochemical properties. | three monoclonal antibodies (mabs) against naja naja atra phospholipase a2 (pla2) were prepared by hybridoma technique. of which two mabs, 1e531 and 5f92 inhibited the enzymatic activity of pla2, but 5f6f10 did not. 1e531 and 5f92 nearly exhibited the same binding patterns which was different from that observed with 5f6f10 toward the chemically modified derivatives and homologous variants of pla2 as revealed by enzyme immunoassay. this suggests that, based on the results of comparative analysis ... | 1991 | 1953802 |
| amino acid sequences of nerve growth factors derived from cobra venoms. | amino acid sequences of nerve growth factors (ngfs), purified from the venoms of indian cobra (naja naja) and thailand cobra (naja naja siamensis) were determined. the sequence of n. naja ngf differed from that reported previously by hogue-angeletti et al. [(1976) biochemistry 15, 26-34]. the sequence of n. naja siamensis ngf was identical to that of formosan cobra naja naja atra ngf, determined previously by oda et al. [(1989) biochem. int. 19, 909-917] and to that deduced from the nucleotide s ... | 1991 | 1995338 |
| a non-radioactive receptor assay for snake venom postsynaptic neurotoxins. | a non-radioactive assay was developed for detecting the binding of postsynaptic neurotoxins to acetylcholine receptor (achr) from torpedo californica. enzyme linked immunosorbent assay (elisa) wells coated with long or short chain neurotoxins specifically bound to purified achr while crotamine or two different cardiotoxins did not. bound receptor was detected by antibody against achr. specificity was determined by dose-response experiments and competition studies using carbamylcholine chloride, ... | 1991 | 1862522 |
| production and characterization of monoclonal antibodies against naja naja atra cobrotoxin. | twelve monoclonal antibodies against cobrotoxin from naja naja atra venom were tested for cross-reactivity with eight different snake toxins, binding to linear epitopes, prevention of cobrotoxin binding to acetylcholine receptor (achr) in vitro, and protection in mice concomitantly given a lethal dose of cobrotoxin. the antibodies were highly specific, as evidenced by little reactivity with other snake toxins. none of the monoclonal antibodies bound to reduced cobrotoxin or synthesized 8-mer reg ... | 1991 | 1724806 |
| two-dimensional nmr studies and secondary structure of cobrotoxin in aqueous solution. | the 1h-nmr spectra of cobrotoxin, a neurotoxic protein isolated from formosan cobra naja naja atra, have been studied by two-dimensional nmr techniques. of 62 amino acid residues in cobrotoxin, the complete assignments of 58 residues have been made. the resonances from several of the remaining residues have been identified but not yet specifically assigned. the secondary structure of an antiparallel triple- and double-stranded beta-sheet has also been determined by observing the noe. | 1990 | 2249693 |
| the effect of cholinergic manipulations on the analgesic response to cobrotoxin in mice. | intracerebroventricular (i.c.v.) injection of cobrotoxin (ct), a neurotoxin isolated from the venom of naja naja atra, produced an antinociceptive response in mice as measured by the tail-flick test. this effect of ct was blocked by systemic administration of atropine, but not by methylatropine or naloxone. depletion of central acetylcholine (ach) by hemicholinium-3 (hc-3) blocked the antinociceptive action of cobrotoxin. these results suggest that central cholinergic neurons are important for t ... | 1990 | 2266778 |
| amino acid sequences of cytotoxin-like basic proteins derived from cobra venoms. | amino acid sequences of cytotoxin-like basic proteins (clbps), purified from the venoms of formosan cobra (naja naja atra) and indian cobra (naja naja), were reinvestigated. the determined sequences differed from those reported previously by takechi et al. [(1985) biochem. int. 11, 795-802; (1987) biochem. int. 14, 145-152]. the sequence of clbps at residues 25-30 was found to be hydrophilic as compared with those of cytotoxins. the difference in the hydrophobicity of this region might be respon ... | 1989 | 2583280 |
| studies on the status of lysine residues in phospholipase a2 from naja naja atra (taiwan cobra) snake venom. | phospholipase a2 (pla2) from naja naja atra (taiwan cobra) snake venom was subjected to lysine modification with trinitrobenzene sulphonic acid (tnbs), and two major trinitrophenylated (tnp) derivatives, tnp-1 and tnp-2, were separated by h.p.l.c. tnp-1 contained only one tnp group on lys-6 and showed a marked decrease in enzymic activity, but still retained 45% of the lethal toxicity. both lys-6 and lys-65 were modified in tnp-2, and modification of lys-65 caused a further reduction of the leth ... | 1989 | 2511834 |
| step-wise thermal denaturation of cobrotoxin, a snake venom neurotoxin from naja naja atra: a proton nuclear magnetic resonance study. | temperature dependence of proton nuclear magnetic resonance spectra has been followed for cobrotoxin, a postsynaptic neurotoxin from naja naja atra venom. several aromatic amino-acid residues, including the functionally essential trp-29 located at the tip of the central loop of the molecule, have been found to undergo a thermal structural transition above the global thermal denaturation temperature. it is suggested that a local structure around these residues behaves somehow independently of the ... | 1989 | 2803517 |
| unfolding processes of small globular proteins: the two-state vs multi-state model. | 1. the alcohol-induced unfolding of two homologous proteins, neurotoxin and cardiotoxin from taiwan cobra (naja naja atra) venom has been analysed. 2. it is postulated that the unfolding process for both proteins is a multi-state conformational transition. 3. it has been hypothesized that between the compact native state of the protein and its fully unfolded state there exists a quasi-continuous spectrum of conformational metastates of protein species. 4. the population distribution of these met ... | 1983 | 6862085 |
| enhancement of naja naja atra antivenin production in horses. | as the conventional hyperimmunization schedule in horses introduced by tanaka could not produce enough neutralizing antibody against naja naja atra venom, the mixture of carboxymethyl cellulose (cmc)-cobra venom incorporated with adjuvant was used for immunization. the neutralizing antibody produced (30 ld50) seemed to be increased but still not to reach the satisfactory level. by using cmc-cobratoxin adjuvant mixture as an immunizing agent, highly potent antivenin (220 ld50) was obtained. | 1982 | 7183425 |
| participation of an ionizable group with pk 8.55 in the reaction of p-bromophenacyl bromide with his 48 of cobra venom phospholipases a2. | the chemical reaction of p-bromophenacyl bromide (bpb) with his 48 of cobra venom phospholipases a2 (n. naja siamensis, n. naja kaouthia, and n. naja atra) was studied at 25 degrees c and ionic strength 0.1 by following the decreases in the fluorescence intensity of 8-anilino-1-naphthalene sulfonate (ans) and/or in the enzymatic activity. the effect of the bpb concentration on the pseudo-first-order rate constant, chi obs, was studied for the n. naja atra enzyme and the dissociation constants of ... | 1982 | 7096315 |
| purification and characterization of anticomplement factor (cobra venom factor) from the naja naja atra venom. | anticomplement factor (cobra venom factor) from the venom of naja naja atra was purified by means of successive chromatography on deae-cellulose, sephadex g-200 and sepharose cl-6b. the purified anticomplement factor was homogeneous as judged by polyacrylamide discontinuous gel electrophoresis at ph 9.4. the yield from 3.0 g of the crude venom was approx. 28 mg. the molecular weight was estimated to be about 156 000 by sds-polyacrylamide gel electrophoresis. the isoelectric point was about 5.2. ... | 1982 | 6173071 |
| amino acid sequence of a cardiotoxin-like basic polypeptide (clbp) with low cytotoxic activity isolated from the venom of the formosan cobra (naja naja atra). | a cardiotoxin-like basic polypeptide, designated as clbp, was isolated from the venom of naja naja atra by gel filtration on sephadex g-50 followed by cm-cellulose chromatography. the cytotoxicity toward yoshida sarcoma cells and lethal toxicity toward mice of clbp were both one-order lower than those of cardiotoxins and cobrotoxin, respectively. clbp is a single polypeptide consisting of 61 amino acid residues with four intramolecular disulfide linkages. the amino acid sequence of clbp shows a ... | 1985 | 4091854 |
| bindings of ca2+ and substrate analogs to a cobra venom phospholipase a2 in which the alpha-amino group is modified to an alpha-keto group. | the ph dependence of the chemical reaction rate of p-bromophenacyl bromide (bpb) with his 48 of cobra (naja naja atra) venom phospholipase a2, in which the alpha-nh2 group had been selectively modified to an alpha-keto group, was studied at 25 degrees c and ionic strength 0.1 in the absence of ca2+. the ph-dependence curve was monophasic with a midpoint at ph 7.9, which corresponds to the pk value of his 48 of the alpha-nh2-modified enzyme, whereas the curve for the intact enzyme was biphasic, i ... | 1984 | 6530402 |
| [fluorescence characteristics of lysine and arginine residues in venom of naja naja atra]. | | 1984 | 6239506 |
| inactivation of toxin b from the indian cobra by cleavage of a specific bond during limited hydrolysis with trypsin. | two neurotoxins, "toxin b", a long neurotoxin from naja naja, and "cobrotoxin", a short neurotoxin from naja naja atra, were compared with respect to their limited hydrolysis by trypsin and chymotrypsin and its effect on their neurotoxicity. limited hydrolysis of toxin b with trypsin cleaves peptide bonds at arg68-lys69 and arg33-gly34 in the toxin molecule and causes complete loss of the neurotoxicity yielding des-carboxyl terminal toxin b(1-68) nicked at arg33-gly34 in the molecule. on the oth ... | 1984 | 6487344 |
| separation of cardiotoxins (cytotoxins) from the venoms of naja naja and naja naja atra by reversed-phase high-performance liquid chromatography. | | 1983 | 6668340 |
| bindings of cobra venom phospholipases a2 to micelles of n-hexadecylphosphorylcholine. | bindings of cobra venom phospholipases a2 to micelles of n-hexadecylphosphorylcholine were studied by the tryptophyl fluorescence method at 25 degrees c and ionic strength 0.1. the data were analyzed by assuming that the micellar surface has multiple binding sites for the enzyme and these sites are identical and mutually independent. the enzyme binding site was found to accommodate a constant number of substrate (monomer) molecules, n = 10, 5 or 13 for n. naja atra apoenzyme and its ca2+ complex ... | 1983 | 6619110 |
| chemical modification of cobratoxin from the venom of formosan cobra (naja naja atra). | | 1970 | 5313270 |
| [a study of the fractions obtained by chromatography of the venom of naja naja atra on sulphoethyl-sephadex]. | | 1968 | 4971838 |
| effect of naja naja atra venom on cytochrome c oxidase, l-ascorbic acid oxidase, peroxidase, and catalase. | | 1965 | 4287255 |
| the relationship between the dose of taiwan cobra (naja atra) and taiwan habu (trimeresurus mucrosquamatus) venom and time of death in mice. | | 1956 | 13357745 |
| conformation of cobrotoxin in aqueous solution as studied by nuclear magnetic resonance. | the 270-mhz proton nmr spectra of cobrotoxin from naja naja atra were observed in 2h2o solution. the pka value (5.93) of his-32 is slightly lower than the pka value (6.65) of the reference model of n-acetylhistidine methylamide, because of the electrostatic interaction with arg-33 and asp-31. the pka value (5.3--5.4) of his-4 is appreciably low, because of the interaction with the positively charged guanidino group possibly of arg-59. the hydrogen-deuterium exchange rates in 2h2o solution were m ... | 1979 | 43248 |
| [purification by affinity chromatography and properties of the acetylcholinesterase of formosan cobra (naja naja atra) venom (author's transl)]. | the acetylcholinesterase was purified by cm-sephadex chromatography and affinity chromatography on sepharose bound m-[6-(6-aminocaproylamino)caproylamino]phenyltrimethylammonium bromide. the purified enzyme was obtained with a specific activity of 5470 u/mg (1160-fold purification) and a 89% yield. the molecular weight of the native enzyme was estimated to be 144,000. the enzyme is split into two subunits of approximately equal molecular weight (mr 69,000) by sds treatment. it is a glycoprotein ... | 1979 | 536451 |
| immunological researches on the main formosan poisonous snakes, especially on the venoms. vi. natural immunity of naja naja atra. | | 1953 | 13211076 |
| atrase b, a novel metalloprotease with anti-complement and anti-coagulant activity, significantly delays discordant cardiac xenograft rejection. | both the complement and the coagulation systems play important roles in the development of hyperacute or acute antibody-mediated xenograft rejection. atrase b is a novel metalloproteinase isolated from the venom of naja atra. in this study, we investigated the inhibitory effects of atrase b on complement activation and coagulation, as well as the effect on xenograft survival in a discordant xenotransplantation model. | 2020 | 32529740 |
| renaturation of a reduced taiwan cobra cardiotoxin. | refolding of a denatured protein obtained by reducing cardiotoxin from the taiwan cobra with mercaptoethanol has been carried out in aqueous and non-aqueous solutions. oxidation of the reduced protein in 0.05 m phosphate buffer (ph 7.2) resulted in isolating an active protein which showed, as compared to native cardiotoxin, identical conformation and biological activities such as lethality, antigenicity and muscle contracture inducing activity. on the other hand, the reduced protein was undergoi ... | 1978 | 76481 |
| isolation and characterization of nerve growth factor from the venom of naja naja atra. | nerve growth factor was isolated from the venom of naja naja atra by ion exchange and gel permeation chromatography and was found to be homogeneous by disc gel electrophoresis. the molecular weight was estimated to be approximately 20,000 by gel filtration and 22,000 by ultracentrifugation. this protein, which showed an isoelectric point of ph 7.02, probably consists of two subunits of equal molecular weight which are held together or interact with each other noncovalently. the biological activi ... | 1976 | 1002678 |
| the amino acid sequence of cardiotoxin-analogue iv from the venom of naja naja atra. | | 1976 | 992063 |
| amino acid sequence of cardiotoxin-analogue ii from the venom of naja naja atra. | | 1976 | 999683 |
| amino acid sequence of cardiotoxin from the venom of naja naja atra. | | 1976 | 955081 |
| immunochemical studies on cardiotoxin from taiwan cobra venom. | | 1976 | 61249 |
| the chemical synthesis of taiwan cobra venom toxins [proceedings]. | | 1976 | 1014028 |
| chemical studies on phospholipase a from formosan cobra (naja naja atra) venom. | | 1972 | 4512906 |
| the amino acid sequence of cardiotoxin from formosan cobra (naja naja atra) venom. | | 1970 | 5518165 |
| multiplex ligation-dependent probe amplification for simultaneous identification of bungarus multicinctus and its common adulterants in a single assay. | bungarus multicinctus, an important traditional chinese medicine, possesses remarkable medicinal activities, while lots of adulterants from other species were misused as b. multicinctus for its large demand and resource starvation. in order to accurately identify b. multicinctus and its common adulterants such as sinonatrix annularis, xenochrophis flavipunctatus, deinagkistrodon acutus, and naja atra, a simultaneous identification method was designed with multiplex ligation-dependent probe ampli ... | 2020 | 32372964 |
| development of sandwich elisa and lateral flow strip assays for diagnosing clinically significant snakebite in taiwan. | taiwan is an island located in the south pacific, a subtropical region that is home to 61 species of snakes. of these snakes, four species-trimeresurus stejnegeri, protobothrops mucrosquamatus, bungarus multicinctus and naja atra-account for more than 90% of clinical envenomation cases. currently, there are two types of bivalent antivenom: hemorrhagic antivenom against the venom of t. stejnegeri and p. mucrosquamatus, and neurotoxic antivenom for treatment of envenomation by b. multicinctus and ... | 2018 | 30507945 |
| orphan three-finger toxins bind at tissue factor-factor viia interface to inhibit factor x activation: identification of functional site by docking. | three-finger toxins (3ftxs) contribute to toxicity of venomous snakes belonging to the family elapidae. currently, functions of a considerable proportion of 3ftxs are still unknown. here, we describe the function of orphan group i 3ftxs consisting of four members. we also identified a new member of this group by sequencing a transcript isolated from naja naja venom. this transcript, named najalexin, is identical to that previously described 3ftx from naja atra venom gland, and shared high sequen ... | 2018 | 31249954 |
| clinical features, bacteriology, and antibiotic treatment among patients with presumed naja bites in vietnam. | clinical and bacteriological features of cobra (naja) bites are still relatively unknown in vietnam. this study aimed to characterize the clinical and bacteriological characteristics of local wounds in patients with presumed naja spp bite, as well as their antibiotic treatment. | 2020 | 32335010 |
| an examination of the neutralization of in vitro toxicity of chinese cobra (naja atra) venom by different antivenoms. | the chinese cobra (naja atra) is an elapid snake of major medical importance in southern china. we describe the in vitro neurotoxic, myotoxic, and cytotoxic effects of n. atra venom, as well as examining the efficacy of three chinese monovalent antivenoms (n. atra antivenom, gloydius brevicaudus antivenom and deinagkistrodon acutus antivenom) and an australian polyvalent snake antivenom. in the chick biventer cervicis nerve-muscle preparation, n. atra venom (1-10 µg/ml) abolished indirect twitch ... | 2020 | 32992934 |
| inhibition of platelet aggregation and blood coagulation by a p-iii class metalloproteinase purified from naja atra venom. | snake venom metalloproteinases (svmps) are an important component in viperid and crotalid venoms, and these svmps play important and versatile roles in the pathogenesis of snakebite envenoming. the svmps from elapid venoms are not well elucidated compared with those from viperid and crotalid venoms. atrase b is a nonhemorrhagic p-iii svmp purified from the naja atra venom, which possesses a weak fibrinogenolytic activity. in this paper, the activity and mechanism of atrase b against platelet agg ... | 2020 | 32971099 |
| blocking of negative charged carboxyl groups converts naja atra neurotoxin to cardiotoxin-like protein. | naja atra cobrotoxin and cardiotoxin 3 (ctx3) exhibit neurotoxicity and cytotoxicity, respectively. in the present study, we aimed to investigate whether the carboxyl groups of cobrotoxin play a role in structural constraints, thereby preventing cobrotoxin from exhibiting cytotoxic activity. six of the seven carboxyl groups in cobrotoxin were conjugated with semicarbazide. measurement of circular dichroism spectra and trp fluorescence quenching showed that the gross conformation of semicarbazide ... | 2020 | 32846183 |
| proteomic characterization of six taiwanese snake venoms: identification of species-specific proteins and development of a siscapa-mrm assay for cobra venom factors. | deinagkistrodon acutus, trimeresurus stejnegeri, protobothrops mucrosquamatus, daboia russelii siamensis, bungarus multicinctus and naja atra are the six medically important venomous snake species in taiwan. in this study, we characterized and compared their venom protein profiles using proteomic approaches. the major snake venom proteins were identified by gelc-ms/ms and the total venom proteome was characterized by in-solution digestion coupled with lc-ms/ms. a total of 27-52 proteins, categor ... | 2018 | 29929037 |
| anti-inflammatory and immune regulatory actions of naja naja atra venom. | naja naja atra venom (nnav) is composed of various proteins, peptides, and enzymes with different biological and pharmacological functions. a number of previous studies have reported that nnav exerts potent analgesic effects on various animal models of pain. the clinical studies using whole venom or active components have confirmed that nnav is an effective and safe medicine for treatment of chronic pain. furthermore, recent studies have demonstrated that nnav has anti-inflammatory and immune re ... | 2018 | 29495566 |
| characterization of chicken-derived single chain antibody fragments against venom of naja naja atra. | traditional, horse-derived antivenin is currently the most efficient treatment against snake bites. however, it is costly and has unpredictable side effects. thus, alternative, cost-effective strategies for producing antivenin are needed. in this study, we immunized hens with inactivated nna venom proteins from the cobra naja naja atra (nna). purified yolk igy antibodies showed specific anti-nna binding activity comparable to that of the equine-derived antivenin. we used phage display technology ... | 2018 | 30248928 |
| studies on the annual reproductive cycle of the female cobra, naja naja. iv. ovarian histology. | morphological changes of the ovary of the chinese cobra, naja naja, throughout the annual reproductive cycle are described. a single clutch of between 6 and 22 eggs is produced in late june. from july to the following april the ovary remains quiescent and contains small previtellogenic, hydration stage follicles. the growth of an ovarian follicle from a primary oocyte to maturation and ovulation is estimated to take three years. the histology of the germinal epithelium and the follicular granulo ... | 1978 | 30231603 |
| distinctive distribution of secretory phospholipases a₂ in the venoms of afro-asian cobras (subgenus: naja, afronaja, boulengerina and uraeus). | the protein abundances of phospholipases a₂ in cobra venom proteomes appear to vary among cobra species. to determine the unique distribution of snake venom phospholipases a₂ (svpla₂) in the cobras, the svpla₂ activities for 15 cobra species were examined with an acidimetric and a colorimetric assay, using egg yolk suspension and 4-nitro-3-octanoyloxy benzoic acid (noba) as the substrate. the colorimetric assay showed significant correlation between svpla₂ enzymatic activities with the svpla₂ pr ... | 2019 | 30769779 |
| ultrastructure of the tongue and anterior process of the sublingual plica in four species of venomous snakes. | the general histology and ultrastructure of the tongue and anterior process of the sublingual plica of four taiwanese venomous snakes, the chinese cobra (naja naja atra), banded krait (bungarus multicinctus), taiwan habu (trimeresurus mucrosquamatus), and bamboo snake (trimeresurus stejnegeri stejnegeri) are described. the tongue fork exhibits a mid-dorsal invagination that broadens gradually toward its base. no mid-ventral invagination is observed. the epithelial cells on both dorsal and ventra ... | 1991 | 29865528 |