The isolation of an easily reversible postsynaptic toxin from the venom of a sea snake, <i>Laticauda semifasciata</i>

Maeda, Nobuyo; Takagi, Kenji; Tamiya, Nanako; Chen, Yunming; Lee, Chen-Yuan

doi:10.1042/bj1410383

Cited by 36 publications

(12 citation statements)

References 15 publications

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“…Similar conclusions have been reached for cobratoxin where aspartate-31 was modified by conjugation with glycine methyl ester without dramatic loss in activity (Chang et al, 1971). Furthermore, the closely related long neurotoxin LsIII, the binding of which is readily reversible, possesses asparagine at position 31 (Maeda et al, 1974).…”

Section: Discussionsupporting

confidence: 67%

Structure‐activity studies of homologues of short chain neurotoxins from Elapid snake venoms

Harvey¹,

Hider²,

Hodges³

et al. 1984

British J Pharmacology

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1Three neurotoxin homologues (CM10 and CM12 from Naja haje annulifera and S5C10 from Dendroaspis jamesoni kaimosae) and two short neurotoxins (CM14 from Naja haje annulifera and erabutoxin b from Laticauda semifasciata) were examined by circular dichroism (c.d.) and tested for neuromuscular activity on chick biventer cervicis nerve-muscle preparations. 2 All three homologues had acetylcholine receptor blocking activity, as they abolished responses to indirect stimulation, acetylcholine and carbachol but had no effect on responses to direct muscle stimulation. CM10 was only about 5 times less potent than the short neurotoxin CM14; S5C10 and CM12 were respectively 30 and 300 times less active. The block induced by the three homologues, but not by the neurotoxins, was readily reversed by washing. 3 CM10 and CM12 had virtually identical c.d. spectra which were closely similar to those of the neurotoxins. The spectrum of S5C10 indicated changes in the environment of tyrosine-25 and in the position of tryptophan-29. These alterations could distort the 3-dimensional arrangement of the residues postulated to form the receptor binding site. 4 The results with CM10 and CM12 highlight a role for the first loop (residues 6-16) in the binding of neurotoxins to acetylcholine receptors, in addition to the previously postulated reactive site.

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Section: Discussionsupporting

confidence: 67%

Structure‐activity studies of homologues of short chain neurotoxins from Elapid snake venoms

Harvey¹,

Hider²,

Hodges³

et al. 1984

British J Pharmacology

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“…The less significance of Trp29 in this case may be partly due to the lack of strong hydrogen bond of Tyr2.5 and the addition of the disulfide bridge between Cys30 and Cys34. They may distort the optimum structure around Trp29 for full toxicity as suggested previously in the discussion about the less toxicity of Ls III (about one-eighth toxicity of erabutoxins [31]) [7]. It is probable that the decrease of toxicity of the Trp29 moiety is compensated by the addition of some_ residues at the C-terminal in the long-chain neurotoxins and that this is not the case in Ls III because of the lack of such residues.…”

Section: Structure-toxicity Relationships Of the Short-chainmentioning

confidence: 93%

Raman spectrum of toxin B in relation to structure and toxicity

et al. 1976

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“…The neuromuscular blockade induced by toxin LSIII ( Laticauda semifasciata ) in the CBCM was reported to be significantly reversed by washing (Maeda et al ., 1974; Harvey & Rodger, 1978). However, the time to recovery from neuromuscular blockade produced by LSIII increased with increasing concentrations of the toxin used for blockade.…”

Section: Discussionmentioning

confidence: 99%

Neuromuscular effects of candoxin, a novel toxin from the venom of the Malayan krait (Bungarus candidus)

Nirthanan

Charpantier

Gopalakrishnakone

et al. 2003

British J Pharmacology

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1 Candoxin (MW 7334.6), a novel toxin isolated from the venom of the Malayan krait Bungarus candidus, belongs to the poorly characterized subfamily of nonconventional three-finger toxins present in Elapid venoms. The current study details the pharmacological effects of candoxin at the neuromuscular junction. 2 Candoxin produces a novel pattern of neuromuscular blockade in isolated nerve-muscle preparations and the tibialis anterior muscle of anaesthetized rats. In contrast to the virtually irreversible postsynaptic neuromuscular blockade produced by curaremimetic a-neurotoxins, the neuromuscular blockade produced by candoxin was rapidly and completely reversed by washing or by the addition of the anticholinesterase neostigmine. 3 Candoxin also produced significant train-of-four fade during the onset of and recovery from neuromuscular blockade, both, in vitro and in vivo. The fade phenomenon has been attributed to a blockade of putative presynaptic nicotinic acetylcholine receptors (nAChRs) that mediate a positive feedback mechanism and maintain adequate transmitter release during rapid repetitive stimulation. In this respect, candoxin closely resembles the neuromuscular blocking effects of d-tubocurarine, and differs markedly from curaremimetic a-neurotoxins that produce little or no fade. 4 Electrophysiological experiments confirmed that candoxin produced a readily reversible blockade (IC 50 B10 nM) of oocyte-expressed muscle (abgd) nAChRs. Like a-conotoxin MI, well known for its preferential binding to the a/d interface of the muscle (abgd) nAChR, candoxin also demonstrated a biphasic concentration -response inhibition curve with a high-(IC 50 B2.2 nM) and a low-(IC 50 B98 nM) affinity component, suggesting that it may exhibit differential affinities for the two binding sites on the muscle (abgd) receptor. In contrast, curaremimetic a-neurotoxins have been reported to antagonize both binding sites with equal affinity.

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The isolation of an easily reversible postsynaptic toxin from the venom of a sea snake, Laticauda semifasciata

Cited by 36 publications

References 15 publications

Structure‐activity studies of homologues of short chain neurotoxins from Elapid snake venoms

Structure‐activity studies of homologues of short chain neurotoxins from Elapid snake venoms

Raman spectrum of toxin B in relation to structure and toxicity

Neuromuscular effects of candoxin, a novel toxin from the venom of the Malayan krait (Bungarus candidus)

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