cDNA cloning and sequence analysis of six neurotoxin‐like proteins from Chinese continental banded krait

Qian, Youcun; Fan, Chen; Gong, Yi; Yang, Shengli

doi:10.1080/15216549800204362

Cited by 5 publications

(7 citation statements)

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“…Lower structural similarity combined with replacement of critical residues in the functional site may confer distinct pharmacological properties or specificities to these 3FTxs. One of the clusters, BF222 (7 clones) displays sequence similarity (76% identity; 86% similarity) (Figure 2D) to bucain from B. candidus venom [55]; [56] and a neurotoxin homolog NTL4 [57]. Similar to bucain, this toxin may exhibit not-so-potent neurotoxicity.…”

Section: Resultsmentioning

confidence: 99%

Transcriptomic analysis of the venom gland of the red-headed krait (Bungarus flaviceps) using expressed sequence tags

et al. 2010

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BackgroundThe Red-headed krait (Bungarus flaviceps, Squamata: Serpentes: Elapidae) is a medically important venomous snake that inhabits South-East Asia. Although the venoms of most species of the snake genus Bungarus have been well characterized, a detailed compositional analysis of B. flaviceps is currently lacking.ResultsHere, we have sequenced 845 expressed sequence tags (ESTs) from the venom gland of a B. flaviceps. Of the transcripts, 74.8% were putative toxins; 20.6% were cellular; and 4.6% were unknown. The main venom protein families identified were three-finger toxins (3FTxs), Kunitz-type serine protease inhibitors (including chain B of β-bungarotoxin), phospholipase A2 (including chain A of β-bungarotoxin), natriuretic peptide (NP), CRISPs, and C-type lectin.ConclusionThe 3FTxs were found to be the major component of the venom (39%). We found eight groups of unique 3FTxs and most of them were different from the well-characterized 3FTxs. We found three groups of Kunitz-type serine protease inhibitors (SPIs); one group was comparable to the classical SPIs and the other two groups to chain B of β-bungarotoxins (with or without the extra cysteine) based on sequence identity. The latter group may be functional equivalents of dendrotoxins in Bungarus venoms. The natriuretic peptide (NP) found is the first NP for any Asian elapid, and distantly related to Australian elapid NPs. Our study identifies several unique toxins in B. flaviceps venom, which may help in understanding the evolution of venom toxins and the pathophysiological symptoms induced after envenomation.

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Section: Resultsmentioning

confidence: 99%

Transcriptomic analysis of the venom gland of the red-headed krait (Bungarus flaviceps) using expressed sequence tags

et al. 2010

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“…Notably, VIIIa and 3FTx‐LT appears to be conserved in the venoms of both KBf and Bf; they are similar to B. candidus NTX4 and Naja melanoleuca s4c11 (SwissProt P01400), which belong to the ‘orphan group II’[40] or unconventional 3FTx [43]. Another protein 3FTx‐RK (belonging to ‘orphan group III’) is conserved in both KBf venoms, and is very similar to bucain from B. candidus venom [22] and a 3FTx cloned from Bungarus multicinctus (AJ006137 [44]). These 3FTx are present in moderate quantities and their targets remain to be identified.…”

Section: Resultsmentioning

confidence: 99%

Sequences, geographic variations and molecular phylogeny of venom phospholipases and threefinger toxins of eastern India Bungarus fasciatus and kinetic analyses of its Pro31 phospholipases A₂

Tsai

Saha

et al. 2006

The FEBS Journal

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Eight phospholipases A2 (PLAs) and four three‐finger‐toxins (3FTx) from the pooled venom of Bungarus fasciatus (Bf) were previously studied and sequenced, but their expression pattern in individual Bf venom and possible geographic variations remained to be investigated. We herein analyze the individual venom of two Bf specimens from Kolkata (designated as KBf) to address this question. Seven PLAs and five 3FTx were purified from the KBf venoms, and respective cDNAs were cloned from venom glands of one of the snakes. Comparison of their mass and N‐terminal sequence revealed that all the PLAs were conserved in both KBf venoms, but that two of their 3FTx isoforms were variable. When comparing the sequences of these KBf‐PLAs with those published, only one was found to be identical to that of Bf Vb‐2, and the other five were 94–98% identical to those of Bf II, III, Va, VI and XI‐2, respectively. Notably, the most abundant PLA isoforms of Bf and KBf venoms contain Pro31 substitution. They were found to have abnormally low kcat values but high affinity for Ca2+. Phylogenetic analysis based on the sequences of venom group IA PLAs showed a close relationship between Bungarus and Australian and marine Elapidae. As the five deduced sequences of KBf‐3FTx are only 62–82% identical to the corresponding Bf‐3FTx from the pooled venom, the 3FTx apparently have higher degree of individual and geographic variations than the PLAs. None of the KBf‐3FTx was found to be neurotoxic or very lethal; phylogenetic analyses of the 3FTx also revealed the unique evolution of Bf as compared with other kraits.

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“…They all exhibit high sequence similarity with other Wntxs (Fig. 2A) but they are clearly more similar to those from cobras than to those found in kraits, mamba and coral snake venom [4–19].…”

Section: Cloning and Sequencing Of Cdnasmentioning

confidence: 99%

“…(A) Sequence alignment of snake weak neurotoxins. Sequences 1–18 are cobra weak neurotoxins [4–12], while sequences 19–25 are from kraits, coral snakes and mambas [13–19]. Sequences 1–4 were determined in this study.…”

Section: Cloning and Sequencing Of Cdnasmentioning

confidence: 99%

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A synthetic weak neurotoxin binds with low affinity to Torpedo and chicken α7 nicotinic acetylcholine receptors

Poh

Mourier

Thaï

et al. 2002

European Journal of Biochemistry

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Weak neurotoxins from snake venom are small proteins with five disulfide bonds, which have been shown to be poor binders of nicotinic acetylcholine receptors. We report on the cloning and sequencing of four cDNAs encoding weak neurotoxins from Naja sputatrix venom glands. The protein encoded by one of them, Wntx-5, has been synthesized by solid-phase synthesis and characterized. The physicochemical properties of the synthetic toxin (sWntx-5) agree with those anticipated for the natural toxin. We show that this toxin interacts with relatively low affinity (K d ¼ 180 nM) with the muscular-type acetylcholine receptor of the electric organ of T. marmorata, and with an even weaker affinity (90 lM) with the neuronal a7 receptor of chicken. Electrophysiological recordings using isolated mouse hemidiaphragm and frog cutaneous pectoris nerve-muscle preparations revealed no blocking activity of sWntx-5 at lM concentrations. Our data confirm previous observations that natural weak neurotoxins from cobras have poor affinity for nicotinic acetylcholine receptors.Keywords: snake neurotoxins; nicotinic acetylcholine receptors.During the past three decades, the most ÔobviousÕ venom toxins have been uncovered either because they are present in large amounts and/or because they have been directly associated with the search for an important target. At present, two additional approaches may be considered to discover new toxin functions. One of them is a proteomictype approach, which aims at isolating all components of the ÔtoxinomeÕ [1,2]. The second approach involves investigation of the vast number of venom components that have already been isolated, and sometimes chemically characterized, but whose biological activity still remains mysterious. These functionally unknown components are often classified as miscellaneous types of toxins, even though they usually belong to well-identified structural families [3]. This is the case of the so-called Ôweak neurotoxinsÕ (Wntxs) found in elapid snakes and isolated for the first time 26 years ago from the venom of Naja melanoleuca [4]. Since then, more such toxins have been isolated [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].The Wntxs possess 62-68 amino acids and belong to the structural family of Ôthree-fingeredÕ folded toxins, which includes the cardiotoxins, muscarinic toxins, acetylcholinesterase inhibitors and the a-neurotoxins that block muscular and/or neuronal nicotinic acetylcholine receptors (AChRs) [20][21][22]. The fold adopted by all these toxins is characterized by three adjacent loops rich in b-pleated sheet, tethered by four conserved disulphides. A fifth loop is sometimes observed in the second loop of the a/j-neurotoxins and j-neurotoxins [22], where it specifically contributes to the binding of the toxins to the neuronal AChR [23][24][25][26]. Wntxs also possess a fifth disulfide bond, but this is located in the first loop [16,27,28].Using Wntxs isolated from venom, it was shown that these molecules interact with AChRs but with low affinities [10,29]. Many ...

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cDNA cloning and sequence analysis of six neurotoxin‐like proteins from Chinese continental banded krait

Cited by 5 publications

References 4 publications

Transcriptomic analysis of the venom gland of the red-headed krait (Bungarus flaviceps) using expressed sequence tags

Transcriptomic analysis of the venom gland of the red-headed krait (Bungarus flaviceps) using expressed sequence tags

Sequences, geographic variations and molecular phylogeny of venom phospholipases and threefinger toxins of eastern India Bungarus fasciatus and kinetic analyses of its Pro31 phospholipases A₂

A synthetic weak neurotoxin binds with low affinity to Torpedo and chicken α7 nicotinic acetylcholine receptors

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cDNA cloning and sequence analysis of six neurotoxin‐like proteins from Chinese continental banded krait

Cited by 5 publications

References 4 publications

Transcriptomic analysis of the venom gland of the red-headed krait (Bungarus flaviceps) using expressed sequence tags

Transcriptomic analysis of the venom gland of the red-headed krait (Bungarus flaviceps) using expressed sequence tags

Sequences, geographic variations and molecular phylogeny of venom phospholipases and threefinger toxins of eastern India Bungarus fasciatus and kinetic analyses of its Pro31 phospholipases A2

A synthetic weak neurotoxin binds with low affinity to Torpedo and chicken α7 nicotinic acetylcholine receptors

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Sequences, geographic variations and molecular phylogeny of venom phospholipases and threefinger toxins of eastern India Bungarus fasciatus and kinetic analyses of its Pro31 phospholipases A₂