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PubMed1992

Structure-function relationship for the highly toxic crotoxin from Crotalus durissus terrificus.

The three-dimensional structure of the highly toxic crotoxin from Crotalus durissus terrificus was modelled based on sequence analysis and the refined structure of calcium-free phospholipase of Crotalus atrox venom. Small-angle x-ray scattering experiments were performed on aqueous solutions of crotoxin. The radial distribution function derived from these scattering experiments and the one calculated from the model structure are in good agreement. Crotoxin consists of a basic and an acidic subunit. The model strongly suggests that the overall folding motif of phospholipases has been preserved in both subunits. The basic domain has an intact active site. The residues that are expected to contact the lipid tails of the phospholipid are different from other phospholipases, but they are all hydrophobic. The acidic domain consists of three independent chains interconnected by disulfide bonds. Compared to other phospholipases the active site for the greater part has been preserved in this domain, but it is not very well shielded from solvent. Most residues normally in contact with the lipid tails of the phospholipid are missing, which might explain the acidic subunit's lack of phospholipase activity. A homology between the third chain of the acidic domain and neurophysins suggests that the acidic domain may act as a chaperone for the basic domain.

Amino Acid Sequence↗

PubMed1975

Studies of an acidic cardiotoxin isolated from the venom of Mojave rattlesnake (Crotalus scutulatus).

A major lethal protein was isolated from the venom of Mojave rattlesnake (Crotalus scutulatus) by successive purification in DEAE column chromatography and isoelectric focusing. This homogeneous and monomeric form of toxin is designated as "Mojave toxin". Unlike basic neurotoxins or cytotoxins isolated from venoms of cobras, kraits and sea snakes, the Mojave toxin is an acidic protein with an isoelectric point of 4.7. The toxin is also different from crotoxin (from Crotalus durissus terrificus) which consists of both acidic and basic components. The molecular weight determined by Sephadex G-75 column chromatography resulted in a value of about 22 000. A singel protein band with a molecular weight of about 12 000, was observed after sodium dodecyl sulfate gel electrophoresis of the reduced Mojave toxin. Isoelectric focusing gel in the presence of 8 M urea also showed a single protein band, suggesting that the toxin is composed of subunits. Unlike the neurotoxic nature of the basic proteins from the venoms of Elapidae and sea snakes (Hydrophiidae) and crotoxin, Mojave toxin is cardiotoxic rather than neurotoxic. It is very likely that venoms of all rattlesnakes from North and Central America contain Mojave toxin as the common toxin.

Amino Acids↗

PubMedDate not supplied

Acute myocardial infarction-like enzyme profile in human victims of Crotalus durissus terrificus envenoming.

The clinical signs and symptoms of Crotalus durissus terrificus envenoming are due to the neurotoxic, myotoxic systemic and thrombin-like coagulating effects of the venom. The rhabdomyolysis observed after envenoming caused by snakes, the venom of which has a systemic myotoxic activity, has been limited thus far to skeletal muscle, with no reports of myocardial damage. In the present paper we report serial measurements of serum creatine kinase (CK), lactic dehydrogenase (LD) and of CK-MB and LD1 isoenzymes in human victims of Crotalus bites. The results were similar to those reported for acute myocardial infarction even though the clinical evolution, electrocardiogram and echocardiogram findings did not show any involvement of cardiac muscle. The enzymatic profile detected, as well as the pattern of focal involvement observed in muscle biopsies obtained from these patients, suggest that there may be a type of skeletal muscle fibre that is preferentially damaged by C. durissus terrificus venom, i.e., type I and/or IIa fibres, the composition of which is richer in CK-MB and LD1, and is similar to that of cardiac fibres.

Adult↗

PubMed1985

Myonecrosis, myoglobinuria and acute renal failure induced by South American rattlesnake (Crotalus durissus terrificus) envenomation in Brazil.

The venom of the Brazilian rattlesnake Crotalus durissus terrificus is know to have hemolytic and neurotoxic physiopathological activities which may cause acute renal failure with hemoglobinuria and/or methemoglobinuria. As far as we know, no report has been published on the ability of the venom of this rattlesnake species to cause rhabdomyolysis. In the present paper we demonstrate that the venom of Brazilian snakes of the genus Crotalus can induce systemic myonecrosis. Clinical, laboratory and anatomo-pathological data for two patients referred to the University Hospital of the Faculty of Medicine of Ribeirão Preto, University of São Paulo, 24 hr after a rattlesnake bite, are presented. In both cases, exaggerated elevation of serum levels of the enzymes creatine phosphokinase, lactate dehydrogenase and glutamic-oxaloacetic transaminase were detected, as well as data suggesting acute hypercatabolic renal failure. Immunoelectrophoresis of the serum and urine of these patients, carried out against specific anti-myoglobin serum (Behringwerke), demonstrated myoglobinemia and myoglobinuria, confirming injury to muscle tissue. Electron microscopy of a calf muscle biopsy taken from the leg contralateral to the bite from one patient revealed foci of myonecrosis.

Acute Kidney Injury↗

PubMed1986

Ability of polyvalent (Crotalidae) antivenom to neutralize local myonecrosis induced by Crotalus atrox venom.

Wyeth's polyvalent (Crotalidae) antivenom was tested in mice for its ability to neutralize local myonecrosis induced by crude Crotalus atrox venom. A light microscopic assay was used to quantitate myonecrosis after i.m. injection of antivenom-venom mixtures. The results indicate that antivenom neutralizes the local myotoxicity of up to 15 micrograms venom per g body weight of mice. This neutralization is significantly better than that previously reported for Crotalus viridis viridis venom.

Animals↗

PubMed1987

A crotoxin homolog from the venom of the Uracoan rattlesnake (Crotalus vegrandis).

A major protein toxin from the venom of Crotalus vegrandis was examined by gel filtration, anion-exchange chromatography, and SDS polyacrylamide gel electrophoresis. The toxin was separated into several isoforms by ion-exchange chromatography and spontaneously dissociated into free acidic and basic subunits, mimicking the behavior of crotoxin. Rabbit antisera raised against crotoxin reacted strongly in enzyme-linked immunosorbent assays with the intact C. vegrandis toxin isoforms and their basic subunits, and formed precipitin lines of identity with intact crotoxin in double immunodiffusion gels. These results indicate that vegrandis toxin is strongly homologous with crotoxin from the venom of Crotalus durissus terrificus.

Animals↗

PubMed1989

Antigenic relationships of fractionated western diamondback rattlesnake (Crotalus atrox) hemorrhagic toxins and other rattlesnake venoms as indicated by monoclonal antibodies.

Seven hemorrhagic factors have been isolated from Crotalus atrox venom, but their antigenic relationships have not been well studied. In this study, two different monoclonal antibodies, C. atrox peak 8 (CA-P-8) and C. atrox subclone 5 (CA-5+), were produced against two C. atrox venom hemorrhagic fractions and used in an ELISA (enzyme-linked immunosorbent assay) to determine if the hemorrhagic factors in C. atrox venom are antigenically related. The same ELISA test was used to determine cross-reactivity of seven other crude Crotalidae venoms. The two monoclonal antibodies were tested for their ability to neutralize each hemorrhagic HPLC fraction separated from C. atrox venom. C. atrox venom was fractionated into 22 fractions using HPLC analytical DEAE ion exchange. Fractions 4-17 were hemorrhagic. The CA-P-8 monoclonal antibody reacted strongly with hemorrhagic fraction 8; CA-5+ had a broader reactivity and reacted with several HPLC hemorrhagic and non-hemorrhagic fractions. Crude venoms of C. adamanteus, C. scutulatus scutulatus and C. viridis lutosus reacted with CA-P-8, while C. viridis lutosus, C. viridis oreganus, C. scutulatus scutulatus and C. horridus horridus reacted with CA-5+. C. molossus molossus and C. lepidus lepidus did not react with CA-P-8 and CA-5+. Hemorrhagic HPLC fractions 6, 7, 8, were completely neutralized by monoclonal antibody CA-P-8; fraction 9 was partially neutralized. The present study indicated that some C. atrox venom HPLC hemorrhagic fractions have both common and unique epitopes. Antigenic determinants were also found to be shared among different Crotalus species.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Amino acid sequence of a myotoxin from venom of the eastern diamondback rattlesnake (Crotalus adamanteus).

The complete amino acid sequence of a myotoxin isolated from Crotalus adamanteus venom (CAM-toxin) was determined. The total number of amino acid residues was 45, giving a mol. wt of 5202. The amino acid sequence was compared with those of previously determined Crotalus myotoxins. The CAM-toxin shows a surprisingly close relationship to those of peptide c (C. v. helleri), myotoxin a (C. v. viridis), crotamine (C. d. terrificus), myotoxin I and II (C. v. concolor) with homologies of approximately 98, 83, 90, 95 and 91%, respectively. The hydropathy profile of the CAM-toxin is almost identical to peptide c and myotoxin I, as can be assumed from the sequence homology. Despite the absence of any close sequence homology with the myotoxic phospholipase A2 enzymes, CAM-toxin contains a similar cationic myotoxic region at residues 2-10 as found in the other five myotoxic peptides.

Amino Acid Sequence↗

PubMedDate not supplied

Inhibition of the proteolytic activity of hemorrhagin-e from Crotalus atrox venom by antihemorrhagins from homologous serum.

Antihemorrhagic proteins from Crotalus atrox serum were tested for their ability to inhibit the proteolytic activity of the hemorrhagic toxin-e from Crotalus atrox venom and of several other proteolytic enzymes: trypsin, collagenase and thermolysin. The antihemorrhagic proteins inhibited the proteolytic activity of hemorrhagin-e when tested on gelatin type I and collagen type IV, the proteolytic activity of trypsin on photofilm gelatin and the proteolytic activity of whole venom when tested on azocollagen and photofilm gelatin. The antihemorrhagins failed to inhibit the proteolytic activity of trypsin when tested on the specific synthetic substrate N-acetyl-DL-phenylalanine-beta-naphthyl ester (APNE), the activity of microbial collagenase on N-(3-[2-furyl]acryloyl)-Leu-Gly-Pro-Ala (FALGPA) or on azocollagen and the activity of thermolysin on N-(3-[2-furyl]acryloyl)-Gly-Leu amide (FAGLA). It is tentatively suggested that the antihemorrhagins from snake blood serum are proteinase inhibitors that underwent specialization towards the neutralization of the proteolytic activity of hemorrhagic toxins.

Amino Acid Sequence↗

PubMed1993

Purification and characterization of two high molecular weight hemorrhagic toxins from Crotalus viridis viridis venom using monoclonal antibodies.

Two high mol. wt hemorrhagic toxins were purified from Crotalus viridis viridis venom using HPLC anion exchange and monoclonal antibody affinity chromatography following initial separation by HPLC with a preparative DEAE column. The fraction from the initial column having the highest hemorrhagic activity was used to immunize BALB/c mice for production of monoclonal antibodies. One of the monoclonal antibodies specifically recognized a single protein band of the immunizing fraction in native polyacrylamide gel electrophoresis. This monoclonal antibody was purified and conjugated to activated membranes for affinity purification of the antigen from the hemorrhagic fraction. Proteins eluted from the affinity membranes showed three bands in SDS-PAGE with apparent mol. wts of 68,000, 62,000 and 30,000. The 68,000 and 62,000 mol. wt proteins were further purified using an analytical DEAE column, and purity was demonstrated by the presence of a single band in SDS-PAGE and a single precipitation arc against antibodies to Crotalus viridis viridis venom in immunoelectrophoresis. The 68,000 (pI of 8.5) and 62,000 (pI of 4.1) proteins are highly hemorrhagic metalloproteinases which cleave N,N-dimethylcasein and fibrinogen. Both are glycoproteins with the same galactose-beta (1-4)-N-acetylglucosamine side-chains linked to asparagine residues. Treatment of both toxins with glycosidase F blocked their hemorrhagic activities. Oxidation of the sugar moieties by periodate inhibited the hemorrhagic activity of the 62,000 toxin, but not of the 68,000 mol. wt toxin.

Animals↗

PubMed1990

Isolation of a crotoxin-like protein from the venom of a South American rattlesnake (Crotalus durissus collilineatus).

1. A crotoxin-like protein was isolated from the venom of a South American rattlesnake Crotalus durissus collilineatus. 2. Many of its properties are similar to those of crotoxin, including its non-covalent heterodimeric structure, electrophoretic mobility on SDS-PAGE, isoelectric focusing properties, toxicity in mice, immunological reactivity, multiple isoforms, phospholipase activity, peptide map, and instability on an anion-exchange column. 3. Results indicate that "collilineatus toxin" is strongly homologous with crotoxin, found in the venom of Crotalus durissus terrificus, and all other characterized rattlesnake neurotoxins.

Animals↗

PubMed1991

A comparative study of the biological activities of rattlesnake (genera Crotalus and Sistrurus) venoms.

1. The hemorrhagic, procoagulant, anticoagulant, protease, arginine ester hydrolase, phosphodiesterase, alkaline phosphomonoesterase, 5'-nucleotidase, hyaluronidase, phospholipase A and L-amino acid oxidase activities of 50 venom samples from 20 taxa of rattlesnake (genera Crotalus and Sistrurus) were examined. 2. The results show that notwithstanding individual variations in the biological activities of Crotalus venoms and the wide ranges of certain biological activities observed, there are some common characteristics at the genus and species levels. 3. The differences in biological activities of the venoms compared can be used for differentiation of the species. Particularly useful for this purpose are the thrombin-like enzyme, protease, arginine ester hydrolase, hemorrhagic and phospholipase A activities and kaolin-cephalin clotting time measurements.

Acetylcholinesterase↗

PubMed2004

Anti-sera raised in rabbits against crotoxin and phospholipase A2 from Crotalus durissus cascavella venom neutralize the neurotoxicity of the venom and crotoxin.

Crotoxin, the principal neurotoxin in venom of the South American rattlesnakes Crotalus durissus terrificus and Crotalus durissus cascavella, contains a basic phospholipase A2 (PLA2) and an acidic protein, crotapotin. In this work, we examined the ability of rabbit anti-sera against crotoxin and its PLA2 subunit to neutralize the neurotoxicity of venom and crotoxin from C. d. cascavella in mouse phrenic nerve-diaphragm and chick biventer cervicis preparations. Immunoblotting showed that the anti-sera recognized C. d. cascavella crotoxin and PLA2. This was confirmed by ELISA, with both anti-sera having end-point dilutions of 3 x 10(-6). Anti-crotoxin serum neutralized the neuromuscular blockade in phrenic nerve-diaphragm muscle preparations at venom or crotoxin:anti-serum ratios of 1:2 and 1:3, respectively. Anti-PLA2 serum also neutralized this neuromuscular activity at a venom or crotoxin:anti-serum ratio of 1:1. In biventer cervicis preparations, the corresponding ratio for anti-crotoxin serum was 1:3 for venom and crotoxin, and 1:1 and 1:2 for anti-PLA2 serum. The neutralizing capacity of the sera in mouse preparations was comparable to that of commercial anti-serum raised against C. d. terrificus venom. These results show that anti-sera against crotoxin and PLA2 from C. d. cascavella venom neutralized the neuromuscular blockade induced by venom and crotoxin in both nerve-muscle preparations, with the anti-serum against crotoxin being slightly less potent than that against crotoxin.

Analysis of Variance↗

PubMed2001

Partial characterization of a basic protein from Crotalus molossus molossus (northern blacktail rattlesnake) venom and production of a monoclonal antibody.

The venom of Crotalus molossus molossus (blacktailed rattlesnake) is very basic compared to that of other Crotalinae venoms. Unlike other Crotalinae venoms that are separated by anion exchange chromatography, C. m. molossus venom must be fractionated by cation exchange chromatography. Electrophoretic titration (ET) was used to predict the isoelectric point (pI) and optimal conditions for isolation. The specific hemorrhagic activity for C. m. molossus venom was 7.5 mm/microg, making it one of the most hemorrhagic of Crotalinae venoms. Basic hemorrhagic and fibrinolytic proteins from the venom of C. m. molossus venom were further fractionated by cation exchange chromatography. A basic fibrinolytic/hemorrhagic protein (CMM4) was isolated. CMM4 has a molecular weight between 23 and 26 kDa and a pI of approximately 11.3. SDS electrophoresis revealed one band and ET curve revealed 3 bands with very similar surface charges at all pH. CMM4 did not activate plasminogen when tested with a Chrom Z-PLG assay. The proteins in CMM4 had similar N-terminal amino acid sequences to each other (D-Q-Q-N-L-P-Q-(S/A/R)-Y-(V/R/I)-E-L-V-V-V-A-D-H-R-L-F-M-K-Y-K-S-D-L- N-T). The differences in these proteins are in positions 8 and 10. CMM4 may contain isoforms that differ by minor sequence variations at their amino-termini. The amino acid sequences of CMM4 were very similar to other fibrinolytic and hemorrhagic metalloproteinases isolated from venoms of the genera Crotalus. The specific hemorrhagic activity of CMM4 decreased as the specific fibrinolytic activity increased. A monoclonal antibody (CMM1b) was produced against C. m. molossus venom that neutralized the hemorrhagic activity of some of its fractions. CMM1b also reacted with 11 of 29 venom samples tested via ELISA.

Amino Acid Sequence↗

PubMed2002

Determination of Crotalus durissus cascavella venom components that induce renal toxicity in isolated rat kidneys.

Envenomation by Crotalus durissus terrificus leads to coagulation disorders, myotoxicity, neurotoxicity and acute renal failure (ARF). The most serious systemic change and primary cause of death is ARF. In this work, we used RP-HPLC to isolate crotoxin, convulxin and gyroxin from venom of the related subspecies Crotalus durissus cascavella and investigated the effects of these toxins on renal function in the isolated rat kidneys perfused with Krebs-Henseleit solution containing 6% of bovine serum albumin. The parameters studied included perfusion pressure (PP), renal vascular resistance (RVR), glomerular filtration rate (GFR), urinary flow (UF), percent of sodium tubular transport (%TNa(+)), percent of potassium tubular transport (%TK(+)) and percent of chloride tubular transport (%TCl(-)). Crotoxin (5 microg/ml) increased the PP, RVR, GFR, UF and decreased %TNa(+), %TK(+) and %TCl(-), with gyroxin (5 micro g/ml) the GFR remained stable during the 120 min of perfusion, whereas PP and RVR increased significantly and the %TNa(+), %TK(+) and %TCl(-) decreased significantly. Convulxin (5 micro g/ml) had no effect on renal function. Crotoxin caused alterations in all renal parameters. Gyroxin produced a minor effect compared to crotoxin. These results indicated that crotoxin is the main componenet responsible for acute nephrotoxicity caused by C. d. cascavella venom.

Animals↗

PubMed2003

Structural and biological characterization of a crotapotin isoform isolated from Crotalus durissus cascavella venom.

Envenoming by Crotalus durissus subspecies leads to coagulation disorders, myotoxicity, neurotoxicity and acute renal failure. The most serious systemic alteration and primary cause of death after snakebite is acute renal failure. In this work, we isolated crotapotin, an acid component (Crtp) of crotoxin from Crotalus durissus cascavella venom and we investigated its bactericidal and pro-inflammatory activities as well as its renal effects in rat isolated perfused kidneys. Crtp was bactericidal to the Gram-negative species Xanthomonas axonopodis pv. passiflorae, but was less effective against the Gram-positive Claribacteri ssp, probably because of differences in the cell wall composition. Crtp showed a high amino acid sequence homology with other Crtps described in the literature (around of 90%) and its A and B chains had high conserved regions corresponding to the calcium-binding loop, catalytic site and helix 3 of PLA2. The Crtp showed moderate pro-inflammatory activity and increased significantly the inflammation evoked by PLA2 when co-injected or co-incubated with PLA2. The renal parameters evaluated included the perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (UF), glomerular filtration rate (GFR) and percent of sodium tubular transport (%TNa+). Crotapotin (5 microg/ml) significantly increased the PP and RVR, whereas the GFR, UF and %TNa+ were unaffected. These results suggest that crotoxin is the main venom component responsible for nephrotoxicity and crotapotin contributes little to this phenomenom. The biological and bactericidal actions of Crtp also suggest that this protein may have functions other than simply acting as a chaperone for PLA2.

Actinomycetales↗

PubMed1989

Preliminary observations on the effects of hyperbaric oxygen therapy on western diamondback rattlesnake (Crotalus atrox) venom poisoning in the rabbit model.

Intermittent hyperbaric oxygen therapy has been shown to reduce skeletal muscle necrosis in a compartment syndrome animal model. To study whether intermittent exposure to hyperbaric oxygen augments antivenin therapy in reducing muscle necrosis, we injected sublethal doses of Western Diamondback rattlesnake (Crotalus atrox) venom intramuscularly into the hind legs of New Zealand White rabbits. In this pilot study, the animals were divided into three treatment groups. The first group received one vial of antivenin intravenously, the second group received one vial of antivenin intravenously plus three hyperbaric oxygen treatments, and the third group received no treatments. There were no statistically significant differences among the groups. These preliminary observations suggest that muscle necrosis secondary to Crotalus atrox venom poisoning is not significantly altered either by Antivenin [Crotalidae] Polyvalent at the dose level we used or in combination with intermittent hyperbaric oxygen treatments in this rabbit model.

Animals↗

PubMed1990

Primary structure of a hemorrhagic metalloproteinase, HT-2, isolated from the venom of Crotalus ruber ruber.

Crotalidae and Viperidae snake venoms contains several kinds of metalloproteinases which cause localized hemorrhage by direct action on blood vessel walls. We report here the entire amino acid sequence and the disulfide bridge locations of HT-2, one of the hemorrhagic toxins isolated from the venom of Crotalus ruber ruber (red rattlesnake). The non-reduced protein was first cleaved at methionine residues to provide a set of 8 fragments, which covered the entire sequence of HT-2. The disulfide bridge locations of HT-2 were also determined by using these primary fragments. The unambiguous sequence for the whole protein was then established by conventional methods using lysyl endopeptidase and thermolysin digests. HT-2 consisted of 202 amino acid residues with two disulfide bridges, which were assigned to Cys-117-Cys-197 and Cys-157-Cys-164. HT-2 had a typical zinc-chelating sequence His-Glu-X-X-His (residues 142-146) found in thermolysin, and its overall sequence showed, respectively, 50, 52, and 53% identities to those of HR2a, H2-proteinase, and the metalloproteinase domain of HR1B. However, the disulfide bridge locations of HT-2 were different from those in the other metalloproteinases. The primary structure of HT-2 was more closely related to that of Ht-d from Crotalus atrox recently determined (81% identity). From the structural comparison with five metalloproteinases so far elucidated, six conservative amino acid residues, which may possibly be related to the induction of the hemorrhagic activity, were suggested to be present in these toxins.

Amino Acid Sequence↗