Isolation and characterization of a presynaptic neurotoxin, P-elapitoxin-Bf1a from Malaysian Bungarus fasciatus venom

Mhd Rusdi Ahmad Rusmili, Ting Yee Tee, Mohd Rais Mustafa, Wayne Clarence Hodgson, Iekhsan Othman

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Presynaptic neurotoxins are one of the major components in Bungarus venom. Unlike other Bungarus species that have been studied, beta-bungarotoxin has never been isolated from Bungarus fasciatus venom. It was hypothesized that the absence of beta-bungarotoxin in this species was due to divergence during evolution prior to evolution of beta-bungarotoxin. In this study, we have isolated a beta-bungarotoxin isoform we named P-elapitoxin-Bf1a by using gel filtration, cation-exchange and reverse-phase chromatography from Malaysian B. fasciatus venom. The toxin consists of two heterogeneous subunits, subunit A and subunit B. LCMS/MS data showed that subunit A was homologous to acidic phospholipase A2 subunit A3 from Bungarus candidus and B. multicinctus venoms, whereas subunit B was homologous with subunit B1 from B. fasciatus venom that was previously detected by cDNA cloning. The toxin showed concentration- and time-dependent reduction of indirect-twitches without affecting contractile responses to ACh, CCh or KCl at the end of experiment in the chick biventer preparation. Toxin modification with 4-BPB inhibited the neurotoxic effect suggesting the importance of His-48. Tissue pre-incubation with monovalent B. fasciatus (BFAV) or neuro-polyvalent antivenom (NPV), at the recommended titer, was unable to inhibit the twitch reduction induced by the toxin. This study indicates that Malaysian B. fasciatus venom has a unique beta-bungarotoxin isoform which was not neutralized by antivenoms. This suggests that there might be other presynaptic neurotoxins present in the venom and there is a variation in the enzymatic neurotoxin composition in venoms from different localities.
Original languageEnglish
Pages (from-to)409 - 416
Number of pages8
JournalBiochemical Pharmacology
Volume91
Issue number3
DOIs
Publication statusPublished - 2014

Cite this

Ahmad Rusmili, Mhd Rusdi ; Tee, Ting Yee ; Mustafa, Mohd Rais ; Hodgson, Wayne Clarence ; Othman, Iekhsan. / Isolation and characterization of a presynaptic neurotoxin, P-elapitoxin-Bf1a from Malaysian Bungarus fasciatus venom. In: Biochemical Pharmacology. 2014 ; Vol. 91, No. 3. pp. 409 - 416.
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Isolation and characterization of a presynaptic neurotoxin, P-elapitoxin-Bf1a from Malaysian Bungarus fasciatus venom. / Ahmad Rusmili, Mhd Rusdi; Tee, Ting Yee; Mustafa, Mohd Rais; Hodgson, Wayne Clarence; Othman, Iekhsan.

In: Biochemical Pharmacology, Vol. 91, No. 3, 2014, p. 409 - 416.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Isolation and characterization of a presynaptic neurotoxin, P-elapitoxin-Bf1a from Malaysian Bungarus fasciatus venom

AU - Ahmad Rusmili, Mhd Rusdi

AU - Tee, Ting Yee

AU - Mustafa, Mohd Rais

AU - Hodgson, Wayne Clarence

AU - Othman, Iekhsan

PY - 2014

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N2 - Presynaptic neurotoxins are one of the major components in Bungarus venom. Unlike other Bungarus species that have been studied, beta-bungarotoxin has never been isolated from Bungarus fasciatus venom. It was hypothesized that the absence of beta-bungarotoxin in this species was due to divergence during evolution prior to evolution of beta-bungarotoxin. In this study, we have isolated a beta-bungarotoxin isoform we named P-elapitoxin-Bf1a by using gel filtration, cation-exchange and reverse-phase chromatography from Malaysian B. fasciatus venom. The toxin consists of two heterogeneous subunits, subunit A and subunit B. LCMS/MS data showed that subunit A was homologous to acidic phospholipase A2 subunit A3 from Bungarus candidus and B. multicinctus venoms, whereas subunit B was homologous with subunit B1 from B. fasciatus venom that was previously detected by cDNA cloning. The toxin showed concentration- and time-dependent reduction of indirect-twitches without affecting contractile responses to ACh, CCh or KCl at the end of experiment in the chick biventer preparation. Toxin modification with 4-BPB inhibited the neurotoxic effect suggesting the importance of His-48. Tissue pre-incubation with monovalent B. fasciatus (BFAV) or neuro-polyvalent antivenom (NPV), at the recommended titer, was unable to inhibit the twitch reduction induced by the toxin. This study indicates that Malaysian B. fasciatus venom has a unique beta-bungarotoxin isoform which was not neutralized by antivenoms. This suggests that there might be other presynaptic neurotoxins present in the venom and there is a variation in the enzymatic neurotoxin composition in venoms from different localities.

AB - Presynaptic neurotoxins are one of the major components in Bungarus venom. Unlike other Bungarus species that have been studied, beta-bungarotoxin has never been isolated from Bungarus fasciatus venom. It was hypothesized that the absence of beta-bungarotoxin in this species was due to divergence during evolution prior to evolution of beta-bungarotoxin. In this study, we have isolated a beta-bungarotoxin isoform we named P-elapitoxin-Bf1a by using gel filtration, cation-exchange and reverse-phase chromatography from Malaysian B. fasciatus venom. The toxin consists of two heterogeneous subunits, subunit A and subunit B. LCMS/MS data showed that subunit A was homologous to acidic phospholipase A2 subunit A3 from Bungarus candidus and B. multicinctus venoms, whereas subunit B was homologous with subunit B1 from B. fasciatus venom that was previously detected by cDNA cloning. The toxin showed concentration- and time-dependent reduction of indirect-twitches without affecting contractile responses to ACh, CCh or KCl at the end of experiment in the chick biventer preparation. Toxin modification with 4-BPB inhibited the neurotoxic effect suggesting the importance of His-48. Tissue pre-incubation with monovalent B. fasciatus (BFAV) or neuro-polyvalent antivenom (NPV), at the recommended titer, was unable to inhibit the twitch reduction induced by the toxin. This study indicates that Malaysian B. fasciatus venom has a unique beta-bungarotoxin isoform which was not neutralized by antivenoms. This suggests that there might be other presynaptic neurotoxins present in the venom and there is a variation in the enzymatic neurotoxin composition in venoms from different localities.

UR - http://www.sciencedirect.com/science/article/pii/S0006295214003888

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DO - 10.1016/j.bcp.2014.07.001

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SP - 409

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JO - Biochemical Pharmacology

JF - Biochemical Pharmacology

SN - 0006-2952

IS - 3

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