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Stephen P Mackessy - One of the best experts on this subject based on the ideXlab platform.
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Colubrid venom composition an omics perspective
Toxins, 2016Co-Authors: Inacio L M Junqueiradeazevedo, Pollyanna Fernandes Campos, Ana Tung Ching Ching, Stephen P MackessyAbstract:Snake venoms have been subjected to increasingly sensitive analyses for well over 100 years, but most research has been restricted to front-fanged snakes, which actually represent a relatively small proportion of extant species of advanced snakes. Because rear-fanged snakes are a diverse and distinct radiation of the advanced snakes, understanding venom composition among “Colubrids” is critical to understanding the evolution of venom among snakes. Here we review the state of knowledge concerning rear-fanged snake venom composition, emphasizing those toxins for which protein or transcript sequences are available. We have also added new transcriptome-based data on venoms of three species of rear-fanged snakes. Based on this compilation, it is apparent that several components, including cysteine-rich secretory proteins (CRiSPs), C-type lectins (CTLs), CTLs-like proteins and snake venom metalloproteinases (SVMPs), are broadly distributed among “Colubrid” venoms, while others, notably three-finger toxins (3FTxs), appear nearly restricted to the Colubridae (sensu stricto). Some putative new toxins, such as snake venom matrix metalloproteinases, are in fact present in several Colubrid venoms, while others are only transcribed, at lower levels. This work provides insights into the evolution of these toxin classes, but because only a small number of species have been explored, generalizations are still rather limited. It is likely that new venom protein families await discovery, particularly among those species with highly specialized diets.
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rna seq and high definition mass spectrometry reveal the complex and divergent venoms of two rear fanged Colubrid snakes
BMC Genomics, 2014Co-Authors: James J Mcgivern, Stephen P Mackessy, Kenneth P Wray, Mark J Margres, Michelle E Couch, Darin R RokytaAbstract:Background Largely because of their direct, negative impacts on human health, the venoms of front-fanged snakes of the families Viperidae and Elapidae have been extensively characterized proteomically, transcriptomically, and pharmacologically. However, relatively little is known about the molecular complexity and evolution of the venoms of rear-fanged Colubrid snakes, which are, with a few notable exceptions, regarded as harmless to humans. Many of these snakes have venoms with major effects on their preferred prey, and their venoms are probably as critical to their survival as those of front-fanged elapids and viperids.
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identification and characterization of a taxon specific three finger toxin from the venom of the green vinesnake oxybelis fulgidus family Colubridae
Biochimie, 2013Co-Authors: William H Heyborne, Stephen P MackessyAbstract:Abstract Snake venoms contain a variety of protein and peptide toxins, and the three-finger toxins (3FTxs) are among the best characterized family of venom proteins. The compact nature and highly conserved molecular fold of 3FTxs, together with their abundance in many venoms, has contributed to their utility in structure-function studies. Although many target the nicotinic acetylcholine receptor of vertebrate skeletal muscle, often binding with nanomolar Kds, several non-conventional 3FTxs show pronounced taxon-specific neurotoxic effects. Here we describe the purification and characterization of fulgimotoxin, a monomeric 3FTx from the venom of Oxybelis fulgidus, a neotropical rear-fanged snake. Fulgimotoxin retains the canonical 5 disulfides of the non-conventional 3FTxs and is highly neurotoxic to lizards; however, mice are unaffected, demonstrating that this toxin is taxon-specific in its effects. Analysis of structural features of fulgimotoxin and other Colubrid venom 3FTxs indicate the presence of a “Colubrid toxin motif” (CYTLY) and a second conserved segment (WAVK) found in Boiga and Oxybelis taxon-specific 3FTxs, both in loop II. Because specific residues in loop II conventional α-neurotoxic 3FTxs are intimately associated with receptor binding, we hypothesize that this loop, with its highly conserved substitutions, confers taxon-specific neurotoxicity. These findings underscore the importance of rear-fanged snake venoms for understanding the evolution of toxin molecules and demonstrate that even among well-characterized toxin families, novel structural and functional motifs may be found.
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Irditoxin, a novel covalently linked heterodimeric three-finger toxin with high taxon-specific neurotoxicity
The FASEB Journal, 2008Co-Authors: Joanna Pawlak, Stephen P Mackessy, Nicole M Sixberry, Enrico Adriano Stura, Renée Ménez, Selvanayagam Nirthanan, Andre Menez, R. Manjunatha KiniAbstract:A novel heterodimeric three-finger neurotoxin, irditoxin, was isolated from venom of the brown treesnake Boiga irregularis (Colubridae). Irditoxin subunit amino acid sequences were determined by Edman degradation and cDNA sequencing. The crystal structure revealed two subunits with a three-finger protein fold, typical for “nonconventional” toxins such as denmotoxin, bucandin, and candoxin. This is the first Colubrid three-finger toxin dimer, covalently connected via an interchain disulfide bond. Irditoxin showed taxon-specific lethality toward birds and lizards and was nontoxic toward mice. It produced a potent neuromuscular blockade at the avian neuromuscular junction (IC50=10 nM), comparable to α-bungarotoxin, but was three orders of magnitude less effective at the mammalian neuromuscular junction. Covalently linked heterodimeric three-finger toxins found in Colubrid venoms constitute a new class of venom peptides, which may be a useful source of new neurobiology probes and therapeutic leads.—Pawlak, J....
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denmotoxin a three finger toxin from the Colubrid snake boiga dendrophila mangrove catsnake with bird specific activity
Journal of Biological Chemistry, 2006Co-Authors: Joanna Pawlak, Stephen P Mackessy, Enrico Adriano Stura, Renée Ménez, Andre Menez, Madhav Bhatia, Gilles Mourier, Carole Fruchartgaillard, Denis Servent, Manjunatha R KiniAbstract:Abstract Boiga dendrophila (mangrove catsnake) is a Colubrid snake that lives in Southeast Asian lowland rainforests and mangrove swamps and that preys primarily on birds. We have isolated, purified, and sequenced a novel toxin from its venom, which we named denmotoxin. It is a monomeric polypeptide of 77 amino acid residues with five disulfide bridges. In organ bath experiments, it displayed potent postsynaptic neuromuscular activity and irreversibly inhibited indirectly stimulated twitches in chick biventer cervicis nerve-muscle preparations. In contrast, it induced much smaller and readily reversible inhibition of electrically induced twitches in mouse hemidiaphragm nerve-muscle preparations. More precisely, the chick muscle α1βγδ-nicotinic acetylcholine receptor was 100-fold more susceptible compared with the mouse receptor. These data indicate that denmotoxin has a bird-specific postsynaptic activity. We chemically synthesized denmotoxin, crystallized it, and solved its crystal structure at 1.9 A by the molecular replacement method. The toxin structure adopts a non-conventional three-finger fold with an additional (fifth) disulfide bond in the first loop and seven additional residues at its N terminus, which is blocked by a pyroglutamic acid residue. This is the first crystal structure of a three-finger toxin from Colubrid snake venom and the first fully characterized bird-specific toxin. Denmotoxin illustrates the relationship between toxin specificity and the primary prey type that constitutes the snake's diet.
Manjunatha R Kini - One of the best experts on this subject based on the ideXlab platform.
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unique gene organization of Colubrid three finger toxins complete cdna and gene sequences of denmotoxin a bird specific toxin from Colubrid snake boiga dendrophila mangrove catsnake
Biochimie, 2008Co-Authors: Joanna Pawlak, Manjunatha R KiniAbstract:Denmotoxin is a Colubrid three-finger toxin isolated from the venom of Boiga dendrophila, which exhibits bird-specific neurotoxicity. We have sequenced the full-length cDNA and the gene encoding the precursor of denmotoxin. This is the first glimpse of genomic organization of a Colubrid three-finger toxin. Denmotoxin cDNA shows low similarity to elapid three-finger toxins, except for the conserved signal peptide region. The open reading frame of denmotoxin possesses an additional fragment encoding a part of the putative signal peptide followed by an extra long N-terminus. The exon/intron organization of denmotoxin is also different from elapid three-finger toxin genes. The denmotoxin gene contains four exons and three introns, while elapid genes share virtually identical gene organization consisting of three exons and two introns. It appears that Elapidae snakes have lost the extra second exon after the divergence of the snake families.
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denmotoxin a three finger toxin from the Colubrid snake boiga dendrophila mangrove catsnake with bird specific activity
Journal of Biological Chemistry, 2006Co-Authors: Joanna Pawlak, Stephen P Mackessy, Enrico Adriano Stura, Renée Ménez, Andre Menez, Madhav Bhatia, Gilles Mourier, Carole Fruchartgaillard, Denis Servent, Manjunatha R KiniAbstract:Abstract Boiga dendrophila (mangrove catsnake) is a Colubrid snake that lives in Southeast Asian lowland rainforests and mangrove swamps and that preys primarily on birds. We have isolated, purified, and sequenced a novel toxin from its venom, which we named denmotoxin. It is a monomeric polypeptide of 77 amino acid residues with five disulfide bridges. In organ bath experiments, it displayed potent postsynaptic neuromuscular activity and irreversibly inhibited indirectly stimulated twitches in chick biventer cervicis nerve-muscle preparations. In contrast, it induced much smaller and readily reversible inhibition of electrically induced twitches in mouse hemidiaphragm nerve-muscle preparations. More precisely, the chick muscle α1βγδ-nicotinic acetylcholine receptor was 100-fold more susceptible compared with the mouse receptor. These data indicate that denmotoxin has a bird-specific postsynaptic activity. We chemically synthesized denmotoxin, crystallized it, and solved its crystal structure at 1.9 A by the molecular replacement method. The toxin structure adopts a non-conventional three-finger fold with an additional (fifth) disulfide bond in the first loop and seven additional residues at its N terminus, which is blocked by a pyroglutamic acid residue. This is the first crystal structure of a three-finger toxin from Colubrid snake venom and the first fully characterized bird-specific toxin. Denmotoxin illustrates the relationship between toxin specificity and the primary prey type that constitutes the snake's diet.
Joanna Pawlak - One of the best experts on this subject based on the ideXlab platform.
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Irditoxin, a novel covalently linked heterodimeric three-finger toxin with high taxon-specific neurotoxicity
The FASEB Journal, 2008Co-Authors: Joanna Pawlak, Stephen P Mackessy, Nicole M Sixberry, Enrico Adriano Stura, Renée Ménez, Selvanayagam Nirthanan, Andre Menez, R. Manjunatha KiniAbstract:A novel heterodimeric three-finger neurotoxin, irditoxin, was isolated from venom of the brown treesnake Boiga irregularis (Colubridae). Irditoxin subunit amino acid sequences were determined by Edman degradation and cDNA sequencing. The crystal structure revealed two subunits with a three-finger protein fold, typical for “nonconventional” toxins such as denmotoxin, bucandin, and candoxin. This is the first Colubrid three-finger toxin dimer, covalently connected via an interchain disulfide bond. Irditoxin showed taxon-specific lethality toward birds and lizards and was nontoxic toward mice. It produced a potent neuromuscular blockade at the avian neuromuscular junction (IC50=10 nM), comparable to α-bungarotoxin, but was three orders of magnitude less effective at the mammalian neuromuscular junction. Covalently linked heterodimeric three-finger toxins found in Colubrid venoms constitute a new class of venom peptides, which may be a useful source of new neurobiology probes and therapeutic leads.—Pawlak, J....
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unique gene organization of Colubrid three finger toxins complete cdna and gene sequences of denmotoxin a bird specific toxin from Colubrid snake boiga dendrophila mangrove catsnake
Biochimie, 2008Co-Authors: Joanna Pawlak, Manjunatha R KiniAbstract:Denmotoxin is a Colubrid three-finger toxin isolated from the venom of Boiga dendrophila, which exhibits bird-specific neurotoxicity. We have sequenced the full-length cDNA and the gene encoding the precursor of denmotoxin. This is the first glimpse of genomic organization of a Colubrid three-finger toxin. Denmotoxin cDNA shows low similarity to elapid three-finger toxins, except for the conserved signal peptide region. The open reading frame of denmotoxin possesses an additional fragment encoding a part of the putative signal peptide followed by an extra long N-terminus. The exon/intron organization of denmotoxin is also different from elapid three-finger toxin genes. The denmotoxin gene contains four exons and three introns, while elapid genes share virtually identical gene organization consisting of three exons and two introns. It appears that Elapidae snakes have lost the extra second exon after the divergence of the snake families.
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denmotoxin a three finger toxin from the Colubrid snake boiga dendrophila mangrove catsnake with bird specific activity
Journal of Biological Chemistry, 2006Co-Authors: Joanna Pawlak, Stephen P Mackessy, Enrico Adriano Stura, Renée Ménez, Andre Menez, Madhav Bhatia, Gilles Mourier, Carole Fruchartgaillard, Denis Servent, Manjunatha R KiniAbstract:Abstract Boiga dendrophila (mangrove catsnake) is a Colubrid snake that lives in Southeast Asian lowland rainforests and mangrove swamps and that preys primarily on birds. We have isolated, purified, and sequenced a novel toxin from its venom, which we named denmotoxin. It is a monomeric polypeptide of 77 amino acid residues with five disulfide bridges. In organ bath experiments, it displayed potent postsynaptic neuromuscular activity and irreversibly inhibited indirectly stimulated twitches in chick biventer cervicis nerve-muscle preparations. In contrast, it induced much smaller and readily reversible inhibition of electrically induced twitches in mouse hemidiaphragm nerve-muscle preparations. More precisely, the chick muscle α1βγδ-nicotinic acetylcholine receptor was 100-fold more susceptible compared with the mouse receptor. These data indicate that denmotoxin has a bird-specific postsynaptic activity. We chemically synthesized denmotoxin, crystallized it, and solved its crystal structure at 1.9 A by the molecular replacement method. The toxin structure adopts a non-conventional three-finger fold with an additional (fifth) disulfide bond in the first loop and seven additional residues at its N terminus, which is blocked by a pyroglutamic acid residue. This is the first crystal structure of a three-finger toxin from Colubrid snake venom and the first fully characterized bird-specific toxin. Denmotoxin illustrates the relationship between toxin specificity and the primary prey type that constitutes the snake's diet.
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Snake venom glutaminyl cyclase.
Toxicon, 2006Co-Authors: Joanna Pawlak, R. Manjunatha KiniAbstract:Glutaminyl cyclase (QC) catalyzes N-terminal glutamine cyclization of many endocrine peptides and is typically abundant in brain tissue. As three-finger toxins in the venoms of Colubrid snakes Boiga dendrophila and Boiga irregularis contain N-terminal pyroglutamate, we searched for QC in venom glands of both snakes. Here we report cDNA sequences of QC from brain and venom gland tissues of Boiga species. We propose that QC expressed in snake venom gland tissue plays a role in the N-terminal pyroglutamate formation of several snake venom toxins, indirectly contributing to venom potency.
Kenneth V Kardong - One of the best experts on this subject based on the ideXlab platform.
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Colubrid snakes and duvernoy s venom glands
Journal of Toxicology-toxin Reviews, 2002Co-Authors: Kenneth V KardongAbstract:One of the largest groups of snakes is the family Colubridae. This is a paraphyletic assemblage that includes a few venomous species, but most pose no special health risk to humans. Thirty to forty percent of Colubrids possess a Duvernoy's gland, a specialized oral gland located in the temporal region. Although it is a homologue to the venom glands of viperid and elapid snakes, the Duvernoy's gland is anatomically and functionally distinct. Generally it lacks a large internal reservoir of secretion, emptying is under low-pressure flow, and the secretion is not delivered via hollow fangs. In contrast, true venom glands hold a large store of ready venom, expel the venom under direct action of striated muscles, and inject it as a high-pressure pulse via hollow fangs. Both the Duvernoy's gland and the venom gland are part of a snake's trophic system, involved primarily in predatory behavior. True venoms are composed of potent toxins whose main biological role is to bring about rapid prey death. Although the s...
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properties of duvernoy s secretions from opisthoglyphous and aglyphous Colubrid snakes
Toxicon, 1994Co-Authors: Scott A Weinstein, Kenneth V KardongAbstract:Relatively little attention has been given to the biological properties of Duvernoy's secretions produced by opisthoglyphous and some aglyphous Colubrid snakes. A review is presented of literature pertaining to these secretions. Most detailed analyses of Duvernoy's secretions and their biological properties have been performed since the late 1970s. The dispholidines, Dispholidus typus and Thelotornis sp., and the natricines, Rhabdophis tigrinus and R. subminiata, have received the most attention due to the high toxicity of their secretions and their medical importance. These species produce secretions with variably strong prothrombin-activating activity, defibrinating activity, and hemorrhagic potential. Boigines, and natricines other than Rhabdophis, produce secretions of low to moderate toxicity and are variably hemorrhagic and proteolytic. Xenodontines and homalopsines similarly show hemorrhagic potential with low to moderate toxicity. Neurotoxic activity has been reported only from secretions of the boigines, Boiga blandingi and B. irregularis and the xenodontine, Heterodon platyrhinos. These species produce secretions containing postsynaptically acting components. Analyses of some of these secretions have shown that enzymes common to many ophidian venoms such as phospholipases A and l-amino acid oxidase are uncommon in the Colubrid secretions studied. This may be due to few studies assaying for multiple enzyme activities and/or the unavailability of many secretion samples for study. Methods of secretion extraction, storage, and assay are discussed. Projected future research and the adaptive implications of Duvernoy's secretions are considered.
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delivery of duvernoy s secretion into prey by the brown tree snake boiga irregularis serpentes Colubridae
Toxicon, 1993Co-Authors: William K Hayes, Pablo Lavinmurcio, Kenneth V KardongAbstract:Many Colubrid snakes, like the more venomous elapid and viperid snakes, can produce and inject an oral secretion that is toxic and may present a human health risk. However, Colubrid oral toxins are produced in a Duvernoy's gland and delivered not through a hollow fang, but instead by long, often grooved teeth under low pressure. The possible role of Duvernoy's secretion in functions other than rapid killing of prey make it important to know how and where this secretion is delivered during a feeding strike. We used ELISA analysis to determine the quantity and proportional distribution of Duvernoy's secretion delivered into the integument compared to the viscera during a feeding strike by the Colubrid snake Boiga irregularis. We determined that only about 54% (1–5 mg) of the secretion actually reached the viscera and that the rest remained in the integument. The amount reaching the viscera is about three to eight times the i.p. ld50 for mice, but these snakes depend more on constriction than toxins to kill their prey. Consequently, delivery of Duvernoy's secretion by B. irregularis is hypothesized to be part of a digestive function and its toxic properties a by-product of this role.
William H Heyborne - One of the best experts on this subject based on the ideXlab platform.
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identification and characterization of a taxon specific three finger toxin from the venom of the green vinesnake oxybelis fulgidus family Colubridae
Biochimie, 2013Co-Authors: William H Heyborne, Stephen P MackessyAbstract:Abstract Snake venoms contain a variety of protein and peptide toxins, and the three-finger toxins (3FTxs) are among the best characterized family of venom proteins. The compact nature and highly conserved molecular fold of 3FTxs, together with their abundance in many venoms, has contributed to their utility in structure-function studies. Although many target the nicotinic acetylcholine receptor of vertebrate skeletal muscle, often binding with nanomolar Kds, several non-conventional 3FTxs show pronounced taxon-specific neurotoxic effects. Here we describe the purification and characterization of fulgimotoxin, a monomeric 3FTx from the venom of Oxybelis fulgidus, a neotropical rear-fanged snake. Fulgimotoxin retains the canonical 5 disulfides of the non-conventional 3FTxs and is highly neurotoxic to lizards; however, mice are unaffected, demonstrating that this toxin is taxon-specific in its effects. Analysis of structural features of fulgimotoxin and other Colubrid venom 3FTxs indicate the presence of a “Colubrid toxin motif” (CYTLY) and a second conserved segment (WAVK) found in Boiga and Oxybelis taxon-specific 3FTxs, both in loop II. Because specific residues in loop II conventional α-neurotoxic 3FTxs are intimately associated with receptor binding, we hypothesize that this loop, with its highly conserved substitutions, confers taxon-specific neurotoxicity. These findings underscore the importance of rear-fanged snake venoms for understanding the evolution of toxin molecules and demonstrate that even among well-characterized toxin families, novel structural and functional motifs may be found.
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venom of the brown treesnake boiga irregularis ontogenetic shifts and taxa specific toxicity
Toxicon, 2006Co-Authors: Stephen P Mackessy, Nicole M Sixberry, William H Heyborne, Thomas FrittsAbstract:The Brown Treesnake (Boiga irregularis), a rear-fanged member of the polyphyletic family Colubridae, is an introduced predator on Guam which has been responsible for numerous human envenomations. Because little is known about this species’ venom, we characterized venom proteins from B. irregularis using enzyme assays, one and 2D electrophoresis, Western blot analysis, mass spectrometry, HPLC and toxicity assays. Venom yields and protein content varied significantly with snake size, and large adult specimens averaged over 500 ml venom (19.2 mg, protein content w90%). Only two enzymes, azocaseinolytic metalloprotease and acetylcholinesterase, were detected in venoms, and both activities increased with snake size/age. Western blot analysis demonstrated a 25 kDa CRiSP homolog in venoms from both neonate and adult snakes. 2D electrophoresis showed variation between venoms from neonate and adult snakes, especially with respect to metalloprotease and acetylcholinesterase. Analysis by MALDI-TOF mass spectrometry revealed the presence of numerous proteins with molecular masses of w8.5‐11 kDa. Adult B. irregularis venom was quite toxic to domestic chickens (Gallus domesticus; 1.75 mg/g) and lizards (Hemidactylus geckos: 2.5 mg/g and Carlia skinks: 4.5 mg/g), and intoxication was characterized by rapid paralysis of all species and neck droop in chickens. Toxicity of venom from neonates toward geckos was 1.1 mg/g, consistent with the presence of a greater diversity of 8‐11 kDa proteins (suspected neurotoxins) in these venoms. All of these values were notably lower than murine LD50 values (neonate: 18 mg/g; adult: 31 mg/g). Like venoms of several front-fanged species, B. irregularis venom showed an ontogenetic shift in enzyme activities and toxicity, and neonate snakes produced more toxic venoms with lower protease and acetylcholinesterase activities. High toxicity toward non-mammalian prey demonstrated the presence of taxaspecific effects (and thus toxins) in B. irregularis venom, likely a characteristic of many Colubrid snake venoms. We hypothesize that the lack of significant envenomation effects in humans following most Colubrid bites results from this taxaspecific action of Colubrid venom components, not from a lack of toxins.