Oxotoxins, or oxytoxins, are a group of neurotoxins present in the venom of lynx spiders belonging to the genus Oxyopes, hence the name oxytoxin. They are disulfide-rich peptides. Only two types are so far reported from two different species, the larger oxytoxin 1 (OxyTx1) from Oxyopes kitabensis, and the smaller oxytoxin 2 (OxyTx2) from Oxyopes lineatus. OxyTx1, the first known oxytoxin, was discovered in 2002. It was found to enhance the lethal efficacy of the spider venom by acting together with oxyopinins.[1] It is composed of 69 amino acid residue, which are cross-linked by five disulfide bridges. It is a large peptide having a molecular mass of 8059.2 Da; but shows the size of 9,109.4 Da due to the presence of disulfide bridges. It is a potent insecticide, but non-toxic to mice up to 1 μg/20-g mouse. It acts synergistically with oxyopinins of the same venom to increase the insecticidal effect.
Both OxyTx1 and OxyTx2 were isolated in 2008 from O. lineatus.[2] Both of these toxins were found to block voltage-sensitive calcium ion channels. OxyTx2 is made up of 55 amino acid residues and has a molecular mass 6175.2 Da. It is less effective in causing paralysis in Spodoptera litura larvae than Oxytx1.
Typesedit
Oxotoxins are classified as follows:
Name
Recommended name
Size in Da
Amino acid residue
Toxicity (LD50) on S. litura
Oxytoxin 1
Omega-oxotoxin-Ol1a
8058.2
69
5.0 nmol/g
Oxytoxin 2
Omega-oxotoxin-Ol1b
6,186
55
weak activity
Referencesedit
^Corzo G, Villegas E, Gómez-Lagunas F, Possani LD, Belokoneva OS, Nakajima T (2002). "Oxyopinins, large amphipathic peptides isolated from the venom of the wolf spider Oxyopes kitabensis with cytolytic properties and positive insecticidal cooperativity with spider neurotoxins". J Biol Chem. 277 (26): 23627–23637. doi:10.1074/jbc.M200511200. PMID 11976325.
^Villegas E, Adachi-Akahane S, Bosmans F, Tytgat J, Nakajima T, Corzo G (2008). "Biochemical characterization of cysteine-rich peptides from Oxyopes sp. venom that block calcium ion channels". Toxicon. 52 (2): 228–236. doi:10.1016/j.toxicon.2008.05.019. PMID 18606178.
External linksedit
Profile at UniProt
ArachnoServer:Spider toxin database
Bioactive Database
December 12, 2023
oxotoxin, confused, with, oxytocin, oxyopinin, oxytoxins, group, neurotoxins, present, venom, lynx, spiders, belonging, genus, oxyopes, hence, name, oxytoxin, they, disulfide, rich, peptides, only, types, reported, from, different, species, larger, oxytoxin, o. Not to be confused with oxytocin or oxyopinin Oxotoxins or oxytoxins are a group of neurotoxins present in the venom of lynx spiders belonging to the genus Oxyopes hence the name oxytoxin They are disulfide rich peptides Only two types are so far reported from two different species the larger oxytoxin 1 OxyTx1 from Oxyopes kitabensis and the smaller oxytoxin 2 OxyTx2 from Oxyopes lineatus OxyTx1 the first known oxytoxin was discovered in 2002 It was found to enhance the lethal efficacy of the spider venom by acting together with oxyopinins 1 It is composed of 69 amino acid residue which are cross linked by five disulfide bridges It is a large peptide having a molecular mass of 8059 2 Da but shows the size of 9 109 4 Da due to the presence of disulfide bridges It is a potent insecticide but non toxic to mice up to 1 mg 20 g mouse It acts synergistically with oxyopinins of the same venom to increase the insecticidal effect Both OxyTx1 and OxyTx2 were isolated in 2008 from O lineatus 2 Both of these toxins were found to block voltage sensitive calcium ion channels OxyTx2 is made up of 55 amino acid residues and has a molecular mass 6175 2 Da It is less effective in causing paralysis in Spodoptera litura larvae than Oxytx1 Types editOxotoxins are classified as follows Name Recommended name Size in Da Amino acid residue Toxicity LD50 on S lituraOxytoxin 1 Omega oxotoxin Ol1a 8058 2 69 5 0 nmol gOxytoxin 2 Omega oxotoxin Ol1b 6 186 55 weak activityReferences edit Corzo G Villegas E Gomez Lagunas F Possani LD Belokoneva OS Nakajima T 2002 Oxyopinins large amphipathic peptides isolated from the venom of the wolf spider Oxyopes kitabensis with cytolytic properties and positive insecticidal cooperativity with spider neurotoxins J Biol Chem 277 26 23627 23637 doi 10 1074 jbc M200511200 PMID 11976325 Villegas E Adachi Akahane S Bosmans F Tytgat J Nakajima T Corzo G 2008 Biochemical characterization of cysteine rich peptides from Oxyopes sp venom that block calcium ion channels Toxicon 52 2 228 236 doi 10 1016 j toxicon 2008 05 019 PMID 18606178 External links editProfile at UniProt ArachnoServer Spider toxin database Bioactive Database Retrieved from https en wikipedia org w index php title Oxotoxin amp oldid 1051920932, wikipedia, wiki, book, books, library,
