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Insecticidal activity of a recombinant knottin peptide from Loxosceles intermedia venom and recognition of these peptides as a conserved family in the genus
Author(s) -
Matsubara F. H.,
Meissner G. O.,
Herzig V.,
Justa H. C.,
Dias B. C. L.,
TrevisanSilva D.,
Gremski L. H.,
Gremski W.,
SenffRibeiro A.,
Chaim O. M.,
King G. F.,
Veiga S. S.
Publication year - 2017
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1111/imb.12268
Subject(s) - biology , venom , peptide , recombinant dna , peptide sequence , biochemistry , gene
Loxosceles intermedia venom comprises a complex mixture of proteins, glycoproteins and low molecular mass peptides that act synergistically to immobilize envenomed prey. Analysis of a venom‐gland transcriptome from L. intermedia revealed that knottins, also known as inhibitor cystine knot peptides, are the most abundant class of toxins expressed in this species. Knottin peptides contain a particular arrangement of intramolecular disulphide bonds, and these peptides typically act upon ion channels or receptors in the insect nervous system, triggering paralysis or other lethal effects. Herein, we focused on a knottin peptide with 53 amino acid residues from L. intermedia venom. The recombinant peptide, named U 2 ‐sicaritoxin‐Li1b (Li1b), was obtained by expression in the periplasm of Escherichia coli . The recombinant peptide induced irreversible flaccid paralysis in sheep blowflies. We screened for knottin‐encoding sequences in total RNA extracts from two other Loxosceles species, Loxosceles gaucho and Loxosceles laeta , which revealed that knottin peptides constitute a conserved family of toxins in the Loxosceles genus. The insecticidal activity of U 2 ‐SCTX‐Li1b, together with the large number of knottin peptides encoded in Loxosceles venom glands, suggests that studies of these venoms might facilitate future biotechnological applications of these toxins.