Oxyopinins are a group of peptide toxins present in the venom of

lynx spider Lynx spider (Oxyopidae) is a family of araneomorph spiders first described by Tamerlan Thorell in 1870. Most species make little use of webs, instead spending their lives as hunting spiders on plants. Many species frequent flowers in particular, ...

s belonging to the genus ''

Oxyopes ''Oxyopes'' is a genus of lynx spiders found worldwide. It includes arounds 300 species and is classified under the lynx spider family Oxyopidae. Like other lynx spiders, they are easily recognizable by the six larger eyes arranged hexagonally on ...

'', from which they derive their name.

Properties

Oxyopinins have

antimicrobial An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...

haemolytic Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...

, and

insecticidal Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...

activities. They are the largest linear cationic

amphipathic An amphiphile (from the Greek αμφις amphis, both, and φιλíα philia, love, friendship), or amphipath, is a chemical compound possessing both hydrophilic (''water-loving'', polar) and lipophilic (''fat-loving'') properties. Such a compoun ...

peptides detected in the venom of any spider. They are structurally α-helical peptides.

Subtypes

The first five peptides, namely oxyopinins 1, 2a, 2b, 2c, and 2d, were described in 2002 from ''

Oxyopes kitabensis ''Oxyopes takobius'' is a species of spiders in the genus ''Oxyopes'' of the lynx spider family, Oxyopidae. The species was first described in 1969, and is found from Central Asia to China. Its venom contains a peptide toxin called oxyopinin (oxy ...

''. Oxyopinin 1 is composed of 48 amino acid residues, with a molecular mass of 5221.2 Da. It has significant amino acid sequence similarity to other venoms of other animals. For example, it has 20% sequence similarity with the ant insecticidal peptide ponericinL2. It is also 29% identical to the amino acid residues of the frog antimicrobial peptide

dermaseptin Dermaseptins are a family of peptides isolated from skin of the frog genus ''Phyllomedusa''. The sequence of the dermaseptins varies greatly but due to the presence of lysine residues all are cationic and most have the potential to form amphipath ...

. Oxyopinins 2a, 2b, 2c, and 2d (originally designated oxyopinins 2, 3, 4, and 5 respectively) are very similar in their sequences. At least 27 out of 37 their amino acid residues are conserved, that is, identical. Their molecular sizes are 4127.1, 4146.9, 4064.7, and 4156.8 Da respectively. All the oxyopinins indicate their secondary structure essentially as alpha-helical. They cause disruption of both biological membranes and artificial vesicles, particularly to those rich in

phosphatidylcholine Phosphatidylcholines (PC) are a class of phospholipids that incorporate choline as a headgroup. They are a major component of biological membranes and can be easily obtained from a variety of readily available sources, such as egg yolk or soyb ...

. They act together with neurotoxins called

oxytoxin 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 spe ...

s from the same venom for increased effectiveness as insecticide. The sixth peptide oxyopinin 4a (Oxt-4a) was reported in 2011 from '' Oxyopes takobius''. It is composed of 77 amino acid residues, and has molecular mass of 9,205 Da. It contains a single

disulfide bond In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...

, Cys4-Cys10, at the N-terminal, which is different from any other spider toxin known so far. Further, unlike other arachnid toxins, Oxt-4a is very similar to defense peptides from the skin of frogs that contain the so-called Rana-box motif (a C-terminal disulfide-enclosed loop).

References

External links

Transporter Classification DatabaseOxyopinin 4a at OPM databaseProfile at COPEUniProt databaseMyBioSourceInformation at Metalife
{{Toxins Spider toxins *Oxyopinin Arachnology Toxins