Characterisation of the heterotrimeric presynaptic phospholipase A 2 neurotoxin complex from the venom of the common death adder (Acanthophis antarcticus)
While Australo-Papuan death adder neurotoxicity is generally considered to be due to the actions of reversible competitive postsynaptic α-neurotoxins, the neurotoxic effects are often poorly reversed by antivenom or anticholinesterases. This suggests that the venom may contain a snake presynaptic ph...
Main Authors: | , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
2010
|
Subjects: | |
Online Access: | http://hdl.handle.net/10453/13734 |
id |
ftunivtsydney:oai:opus.lib.uts.edu.au:10453/13734 |
---|---|
record_format |
openpolar |
spelling |
ftunivtsydney:oai:opus.lib.uts.edu.au:10453/13734 2023-05-15T13:52:42+02:00 Characterisation of the heterotrimeric presynaptic phospholipase A 2 neurotoxin complex from the venom of the common death adder (Acanthophis antarcticus) Blacklow, B Escoubas, P Nicholson, GM 2010-07-01 application/pdf http://hdl.handle.net/10453/13734 unknown Biochemical Pharmacology 10.1016/j.bcp.2010.03.030 Biochemical Pharmacology, 2010, 80 (2), pp. 277 - 287 0006-2952 http://hdl.handle.net/10453/13734 Pharmacology & Pharmacy Presynaptic Terminals Neuromuscular Junction Animals Chickens Elapidae Receptors Presynaptic Elapid Venoms Neurotoxins Biological Assay Chromatography High Pressure Liquid Spectrometry Mass Electrospray Ionization Matrix-Assisted Laser Desorption-Ionization Muscle Contraction Phospholipases A2 Journal Article 2010 ftunivtsydney 2022-03-13T13:37:03Z While Australo-Papuan death adder neurotoxicity is generally considered to be due to the actions of reversible competitive postsynaptic α-neurotoxins, the neurotoxic effects are often poorly reversed by antivenom or anticholinesterases. This suggests that the venom may contain a snake presynaptic phospholipase A2 (PLA2) neurotoxin (SPAN) that binds irreversibly to motor nerve terminals to inhibit neurotransmitter release. Using size-exclusion liquid chromatography under non-reducing conditions, we report the isolation and characterisation of a high molecular mass SPAN complex, P-elapitoxin-Aa1a (P-EPTX-Aa1a), from the venom of the common death adder Acanthophis antarcticus. Using the chick biventer-cervicis nerve-muscle preparation, P-EPTX-Aa1a (44,698Da) caused inhibition of nerve-evoked twitch contractions while responses to cholinergic agonists and KCl remained unaffected. P-EPTX-Aa1a also produced significant fade in tetanic contractions and a triphasic timecourse of neuromuscular blockade. These actions are consistent with other SPANs that inhibit acetylcholine release. P-EPTX-Aa1a was found to be a heterotrimeric complex composed of α, β and γ-subunits in a 1:1:1 stoichiometry with each subunit showing significant N-terminal sequence homology to the subunits of taipoxin, a SPAN from Oxyuranus s. scutellatus. Like taipoxin, only the α-chain produced any signs of neurotoxicity or displayed significant PLA2 enzymatic activity. Preincubation with monovalent death adder antivenom or suramin, or inhibition of PLA2 activity by incubation with 4-bromophenacyl bromide, either prevented or significantly delayed the onset of toxicity by P-EPTX-Aa1a. However, antivenom failed to reverse neurotoxicity. Early intervention with antivenom may therefore be important in severe cases of envenomation by A. antarcticus, given the presence of potent irreversible presynaptic neurotoxins. © 2010 Elsevier Inc. Article in Journal/Newspaper Antarc* antarcticus University of Technology Sydney: OPUS - Open Publications of UTS Scholars |
institution |
Open Polar |
collection |
University of Technology Sydney: OPUS - Open Publications of UTS Scholars |
op_collection_id |
ftunivtsydney |
language |
unknown |
topic |
Pharmacology & Pharmacy Presynaptic Terminals Neuromuscular Junction Animals Chickens Elapidae Receptors Presynaptic Elapid Venoms Neurotoxins Biological Assay Chromatography High Pressure Liquid Spectrometry Mass Electrospray Ionization Matrix-Assisted Laser Desorption-Ionization Muscle Contraction Phospholipases A2 |
spellingShingle |
Pharmacology & Pharmacy Presynaptic Terminals Neuromuscular Junction Animals Chickens Elapidae Receptors Presynaptic Elapid Venoms Neurotoxins Biological Assay Chromatography High Pressure Liquid Spectrometry Mass Electrospray Ionization Matrix-Assisted Laser Desorption-Ionization Muscle Contraction Phospholipases A2 Blacklow, B Escoubas, P Nicholson, GM Characterisation of the heterotrimeric presynaptic phospholipase A 2 neurotoxin complex from the venom of the common death adder (Acanthophis antarcticus) |
topic_facet |
Pharmacology & Pharmacy Presynaptic Terminals Neuromuscular Junction Animals Chickens Elapidae Receptors Presynaptic Elapid Venoms Neurotoxins Biological Assay Chromatography High Pressure Liquid Spectrometry Mass Electrospray Ionization Matrix-Assisted Laser Desorption-Ionization Muscle Contraction Phospholipases A2 |
description |
While Australo-Papuan death adder neurotoxicity is generally considered to be due to the actions of reversible competitive postsynaptic α-neurotoxins, the neurotoxic effects are often poorly reversed by antivenom or anticholinesterases. This suggests that the venom may contain a snake presynaptic phospholipase A2 (PLA2) neurotoxin (SPAN) that binds irreversibly to motor nerve terminals to inhibit neurotransmitter release. Using size-exclusion liquid chromatography under non-reducing conditions, we report the isolation and characterisation of a high molecular mass SPAN complex, P-elapitoxin-Aa1a (P-EPTX-Aa1a), from the venom of the common death adder Acanthophis antarcticus. Using the chick biventer-cervicis nerve-muscle preparation, P-EPTX-Aa1a (44,698Da) caused inhibition of nerve-evoked twitch contractions while responses to cholinergic agonists and KCl remained unaffected. P-EPTX-Aa1a also produced significant fade in tetanic contractions and a triphasic timecourse of neuromuscular blockade. These actions are consistent with other SPANs that inhibit acetylcholine release. P-EPTX-Aa1a was found to be a heterotrimeric complex composed of α, β and γ-subunits in a 1:1:1 stoichiometry with each subunit showing significant N-terminal sequence homology to the subunits of taipoxin, a SPAN from Oxyuranus s. scutellatus. Like taipoxin, only the α-chain produced any signs of neurotoxicity or displayed significant PLA2 enzymatic activity. Preincubation with monovalent death adder antivenom or suramin, or inhibition of PLA2 activity by incubation with 4-bromophenacyl bromide, either prevented or significantly delayed the onset of toxicity by P-EPTX-Aa1a. However, antivenom failed to reverse neurotoxicity. Early intervention with antivenom may therefore be important in severe cases of envenomation by A. antarcticus, given the presence of potent irreversible presynaptic neurotoxins. © 2010 Elsevier Inc. |
format |
Article in Journal/Newspaper |
author |
Blacklow, B Escoubas, P Nicholson, GM |
author_facet |
Blacklow, B Escoubas, P Nicholson, GM |
author_sort |
Blacklow, B |
title |
Characterisation of the heterotrimeric presynaptic phospholipase A 2 neurotoxin complex from the venom of the common death adder (Acanthophis antarcticus) |
title_short |
Characterisation of the heterotrimeric presynaptic phospholipase A 2 neurotoxin complex from the venom of the common death adder (Acanthophis antarcticus) |
title_full |
Characterisation of the heterotrimeric presynaptic phospholipase A 2 neurotoxin complex from the venom of the common death adder (Acanthophis antarcticus) |
title_fullStr |
Characterisation of the heterotrimeric presynaptic phospholipase A 2 neurotoxin complex from the venom of the common death adder (Acanthophis antarcticus) |
title_full_unstemmed |
Characterisation of the heterotrimeric presynaptic phospholipase A 2 neurotoxin complex from the venom of the common death adder (Acanthophis antarcticus) |
title_sort |
characterisation of the heterotrimeric presynaptic phospholipase a 2 neurotoxin complex from the venom of the common death adder (acanthophis antarcticus) |
publishDate |
2010 |
url |
http://hdl.handle.net/10453/13734 |
genre |
Antarc* antarcticus |
genre_facet |
Antarc* antarcticus |
op_relation |
Biochemical Pharmacology 10.1016/j.bcp.2010.03.030 Biochemical Pharmacology, 2010, 80 (2), pp. 277 - 287 0006-2952 http://hdl.handle.net/10453/13734 |
_version_ |
1766257160853913600 |