Membrane-disruptive properties of the bioinsecticide Jaburetox-2Ec: Implications to the mechanism of the action of insecticidal peptides derived from ureases

Jaburetox-2Ec, a recombinant peptide derived from an urease isoform (JBURE-II), displays high insecticidal activity against important pests such as Spodoptera frugiperda and Dysdercus peruvianus. Although the molecular mechanism of action of ureases-derived peptides remains unclear, previous ab initio data suggest the presence of structural motifs in Jaburetox-2Ec with characteristics similar to those found in a class of pore-forming peptides. Here, we investigated the molecular aspects of the interaction between Jaburetox-2Ec and large unilamellar vesicles. Jaburetox-2Ec displays membrane-disruptive ability on acidic lipid bilayers and this effect is greatly influenced by peptide aggregation. Corroborating with this finding, molecular modeling studies revealed that Jaburetox-2Ec might adopt a well-defined P-hairpin conformation similar to those found in antimicrobial peptides with membrane disruption properties. In addition, molecular dynamics simulations suggest that the protein is able to anchor at a polar/non-polar interface. In the light of these findings, for the first time it was possible to point out some evidence that the peptide Jaburetox-2Ec interacting with lipid vesicles promotes membrane permeabilization. (C) 2009 Elsevier B.V. All rights reserved.