1.C.68 The Channel-forming Oxyopinin Peptide (Oxyopinin) Family

Oxyopinins are cationic amphipathic peptides with antimicrobial, hemolytic, and insecticidal activities. They are from the venome of the wolf spider, Oxyopes kitabensis (Corzo et al., 2002). Corzo et al. report that they are similar in sequence to the ant venome insecticidal peptide, ponericin-L2 (P82422), which exhibits antimicrobial activities but has not been shown to exhibit pore-forming activity, and the frog antimicrobial peptide dermaseptin (TC #1.C.52.1.1). If so, they are very distantly related and were not retrieved in a BLAST search.

Oxyopinins are probably α-helical with a single TMS. They disrupt biological and artificial membranes and open oligomeric, non-selective, ion pores (Corzo et al., 2002). They undoubtedly form oligomeric channels.

The transport reaction catalyzed by oxyopinins is:

small molecules (in) small molecules (out)


 

References:

Corzo, G., E. Villegas, F. Gómez-Lagunas, L.D. Possani, O.S. Belokoneva, and T. Nakajima. (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: 23627-23637.

Frazão, B., V. Vasconcelos, and A. Antunes. (2012). Sea anemone (Cnidaria, Anthozoa, Actiniaria) toxins: an overview. Mar Drugs 10: 1812-1851.

Examples:

TC#NameOrganismal TypeExample
1.C.68.1.1Oxyopinin 1 (2a)SpidersOxyopinin 1 of Oxyopes kitabensis (P83248)
 
1.C.68.1.2

Oxyopinin-2c of 37 aas.  Disrupts biological membranes, particularly those rich in phosphatidylcholine. Has antimicrobial activity against E.coli, B.subtilis and S.aureus, and hemolytic activity against sheep, pig and guinea pig red blood cells. Has insecticidal activity against S.frugiperda ovarian cells by opening non-selective ion channels. Enhances the insecticidal activity of spider venom neurotoxic peptides (Corzo et al. 2002).

Spiders

Oxyopinin-2c of Oxyopes kitabensis